BBC Sky at Night 2014-12

ROSETTA: WHAT COMES AFTER LANDING? THE BIGGEST NAME IN ASTRONOMY

Sky at Night 24

E OBSERVING CHALLENG

NIGHTS OF

STARGAZING Count down to Christmas with the season’s most spectacular sights KEPLER’S SECOND COMING The exoplanet hunter returns on a new mission

ALL IN A SPIN The strange shapes of asteroids explained

LUNAR LAVA Deep inside the Moon, a surprise is stirring

FREE 2015 CALENDAR VISIT www.skyatnightmagazine.com/2015-calendar

ALSO THIS ISSUE 1ST FOR GEAR Celestron Cosmos 90GT Wi-Fi telescope PLUS more beginners’ kit

GEMINID METEORS Watch one of the year’s best displays with our expert guide

NEXT-GEN SCOPES A new class of observatories will revolutionise astronomy DECEMBER 2014 #115 www.skyatnightmagazine.com

TECHNOLOGICALLYSUPERIOR

THE WORLD’S MOST LOVED TELESCOPE HAS EVOLVED

The first ever Schmidt-Cassegrain Telescope with fully integrated WiFi Now you can leave your hand control behind and slew to all the best celestial objects with a tap of your smartphone or tablet. Connect your device to NexStar Evolution’s built-in wireless network and explore the universe with the Celestron planetarium app for iOS and Android. 6”, 8” or 9.25” SCT. iPAD and iPHONE SHOWN NOT INCLUDED

Available from specialist astronomy retailers and selected other dealers nationwide. Celestron is distributed in the UK & Ireland by David Hinds Limited. Trade enquiries welcomed.

www.celestron.uk.com Celestron® and NexStar® are registered trademarks of Celestron Acquisition, LLC in the United States and in dozens of other countries around the world. All rights reserved. David Hinds Ltd is an authorised distributor and reseller of Celestron products. The iPhone® and iPad® are trademarks of Apple Inc., registered in the U.S. and other countries.

LETTER FROM THE EDITOR DECEMBER 03

Welcome

This month’s contributors include...

It’s beginning to feel a lot like Christmas...

ALISTER GRAHAM PROFESSOR OF ASTRONOMY

Now that peak firework season has Alister looks back to the passed and we can astrological revel in dark skies roots of the again, we’re bringing science of you a very special astronomy that we know observing tour full of today. Page 74 Christmas cheer: our CAROL LAKOMIAK Advent calendar SKETCHING EXPERT challenge, which Carol writes the last of highlights one top target for each night from her monthly 1-24 December. Of course, many of the sights sketching that Pete Lawrence and Steve Richards have columns, selected are visible on more than just one ending on a festive note night, in case of cloud cover. Discover what’s – the Christmas Tree behind the first door on page 32. Cluster. Page 83 If the clouds do appear, there’s a great project ELIZABETH PEARSON for you to get stuck into on page 80, as we STAFF WRITER show you how to turn your Newtonian scope Elizabeth speaks to into a Dobsonian by making a rocker box base. Rosetta’s Clouds have been the least of worries lately project for the Kepler mission. It’s been out of action scientist to find out what will happen since crucial alignment mechanisms on the craft broke down. But now the plucky probe after the Philae lander is launched. Page 62 is embarking on a new mission, as Will Gater reports on page 38. GOVERT SCHILLING Enjoy the issue and Happy Christmas! ASTRONOMY AUTHOR Govert previews the next generation of giant telescopes being built at observatories around the world. Page 67

Chris Bramley Editor

PS Next issue goes on sale 19 December.

HOW TO CONTACT US binders, CD cases and back issues  Subscriptions, 0844 844 0254 Mon to Fri 8am to 8pm; Sat 9am to 1pm for orders Editorial enquiries 0117 314 7411 9.30am to 5.30pm, Mon to Fri Advertising enquiries 0117 314 8365 email enquiries  Subscription [email protected] Editorial enquiries [email protected] App enquiries http://apps.immediate.co.uk/support [email protected] enquiries

Editorial BBC Sky at Night Magazine, Immediate Media Co Bristol Ltd, Tower House, Fairfax Street, Bristol, BS1 3BN

BECOME AN INSIDER The more we know about what you like, the better placed we are to bring you the best magazine possible. So we would like to invite you to join our online reader panel ‘Insiders’. Just log on to www.immediateinsiders. com/register to fill out the short registration survey and we’ll be in touch from time to time to ask for your opinions on the magazine and other relevant issues. We look forward to hearing from you soon.

Sky at Night LOTS OF WAYS TO ENJOY THE NIGHT SKY...

TELEVISION

ONLINE

FACEBOOK

PODCAST

iPAD

TWITTER

Find out what The Sky at Night team will be exploring in this month’s episode on page 19

Visit our website for reviews, competitions, astrophotos, observing guides and our forum

All the details of our latest issue, plus news from the magazine and updates to our website

The BBC Sky at Night Magazine team discuss the latest astro news in our monthly podcast

Get each month’s issue on your iPad, now with bonus video and extra images

Follow @skyatnightmag to keep up with the latest space stories and tell us what you think

skyatnightmagazine.com 2014

04 CONTENTS DECEMBER

In the magazine THE ADVENT CALENDAR OBSERVING CHALLENGE

NEW TO ASTRONOMY? See The guide on page 78 and our online glossary at www.skyatnightmagazine.com/dictionary

32 REGULARS 06 EYE ON THE SKY

11 BULLETIN The latest space and astronomy news.

19 WHAT’S ON 21 A PASSION FOR SPACE With The Sky at Night co-presenter Maggie Aderin-Pocock.

23 JON CULSHAW Jon’s off-world travelogue continues.

24 INTERACTIVE 26 SUBSCRIBE Get your issues at a discount

FEATURES

28 HOTSHOTS

C = on the cover

Your best astro images revealed.

47 THE SKY

32 THE ADVENT CALENDAR

IN DECEMBER

OBSERVING CHALLENGE C We’ve got a new sight for each night up to Christmas – can you catch them all?

38 THE REBIRTH OF KEPLER C Take a detailed look at the new mission for NASA’s reinvigorated space scope.

90 38

FIRST LIGHT THE REBIRTH OF KEPLER

C Your 15-page guide to the night sky featuring the top sights, an all-sky chart, a deep-sky tour and more…

78 SKILLS 78 The guide The cosmic microwave background.

44 DIRECT TO LOW-

80 How to Build a Dobsonian mount, part 1.

COVER: THINKSTOCK, THIS PAGE: ALAMY, STFC, WWW.THESECRETSTUDIO.NET, NASA/KEPLER MISSION/WENDY STENZEL, ESA/ROSETTA/NAVCAM

EARTH ORBIT

83 Sketching

The future craft that will journey to the ISS.

85 Scope Doctor Your gear problems solved.

62 CAPTURING A

89 REVIEWS

COMET’S HEART C ESA’s Rosetta project scientist tells us what

C

to expect after Philae descends to its comet.

94 Olivon 10x50 QB binoculars.

67 DAWN OF THE

98 Starry Night Pro Plus 7 planetarium software.

SUPERSCOPES

102 Books

C The next generation of telescopes.

104 Gear

74 ASTROLOGY: AN ASTRONOMER’S VIEW A rational look at why star signs don’t add up. skyatnightmagazine.com 2014

First Light 90 Celestron Cosmos 90GT Wi-Fi telescope.

106 WHAT I REALLY

62

WANT TO KNOW IS…

CAPTURING A COMET’S HEART

Is it still hot inside the Moon?

Sky at Night MAGAZINE

Download the complete multimedia experience with our special edition apps MAN ON THE MOON

THE APOLLO STORY

MAN IN SPACE

Man on the Moon celebrates the complete story of Apollo 11: the crew, the spacecraft, the mission, the legend of the historic first steps on the Moon.

The Apollo Story is your complete guide to the greatest journey in human history, featuring the facts, figures and stories from every Apollo mission.

Man in Space celebrates 50 years of mankind’s adventure in space, brought to life by historic video footage and amazing images.

In this app:

In this app:

X AMAZING VIDEO FOOTAGE AND PHOTO GALLERIES X INTERACTIVE DIAGRAMS X PANORAMIC VIEWS OF THE MOON

X GO BEHIND THE SCENES WITH AUDIO AND VIDEO SECTIONS X RARE PHOTOS AND EXHAUSTIVE PICTURE GALLERIES

X 3D VIEWS OF LEGENDARY SPACECRAFT X 360-DEGREE PANORAMIC VIEWS OF THE MOON X A FOREWORD BY SIR PATRICK MOORE

Download your copy today for just £3.99/$5.99!

TAP HERE TO FIND OUT MORE

BBC Sky at Night Magazine is published by Immediate Media Company Bristol Limited under licence from BBC Worldwide, who help fund new BBC programmes.

EDITORIAL Editor Chris Bramley Art Editor Steve Marsh Production Editor Kev Lochun Online Editor Kieron Allen Staff Writer Elizabeth Pearson Reviews Editor Paul Money CONTRIBUTORS Paul Abel, Maggie Aderin-Pocock, Paul F Cockburn, Jon Culshaw, Adam Crute, Lewis Dartnell, Glenn Dawes, Mark Garlick, Will Gater, Alister Graham, Brian Jones, Carol Lakomiak, Pete Lawrence, Chris Lintott, Hazel Muir, Chris North, Steve Richards, Steve Sayers, Govert Schilling, Giles Sparrow, Paul Sutherland, Stephen Tonkin ADVERTISING SALES Advertising Managers Steve Grigg (0117 314 8365), Tony Robinson (0117 314 8811) Inserts Laurence Robertson (00 353 87 690 2208)

Download your copy today for just £4.99/$6.99!

TAP HERE TO FIND OUT MORE PRODUCTION Production Director Sarah Powell Production Manager Derrick Andrews Ad Services Manager Paul Thornton Ad Co-ordinator Emily Thorne Ad Designers Cee Pike, Andrew Hobson Reprographics Tony Hunt, Chris Sutch LICENSING Director of Licensing and Syndication Tim Hudson International Partners’ Manager Anna Brown MARKETING Head of Circulation Rob Brock Head of Marketing Jacky Perales-Morris Marketing Executive Chris Day Head of Press and PR Carolyn Wray (0117 314 8812) PUBLISHING Publisher Jemima Ransome Managing Director Andy Marshall

In this app:

Download your copy today for just £3.99/$5.99!

TAP HERE TO FIND OUT MORE Head of UK Publishing Chris Kerwin UK Publishing Coordinator Eva Abramik [email protected] www.bbcworldwide.com/uk--anz/ukpublishing.aspx EDITORIAL ADVISORY BOARD Deborah Cohen, Andrew Cohen, Michael Ewing, Julian Hector, John Lynch, Jonathan Renouf

SUBSCRIPTION RATES Annual subscription rates (inc P&P): UK cheque/credit card £59.88; Europe & Eire Airmail £69; rest of world airmail £79. To order, call 0844 844 0260

© Immediate Media Company Bristol Limited 2014 ISSN 1745-9869

MANAGEMENT Chairman Stephen Alexander Deputy Chairman Peter Phippen CEO Tom Bureau

All rights reserved. No part of BBC Sky at Night Magazine may be reproduced in any form or by means either wholly or in part, without prior written permission of the publisher. Not to be re-sold, lent or hired out or otherwise disposed of by way of trade at more than the recommended retail price (subject to VAT in the Republic of Ireland) or in mutilated condition. Immediate Media Company Bristol Limited is working to ensure that all of its paper is sourced from well-managed forests. This magazine is printed on Forest Stewardship Council (FSC) certified paper. This magazine can be recycled, for use in newspapers and packaging. Please remove any gifts, samples or wrapping and dispose of it at your local collection point.

BBC WORLDWIDE, UK PUBLISHING Director of UK Publishing Nicholas Brett

The publisher, editor and authors accept no responsibility in respect of any products, goods or services that may be advertised or referred to in this issue for any errors, omissions, mis-statements or mistakes in any such advertisements or references.

skyatnightmagazine.com 2014

A burst

of

colour This composite image of supernova remnant Puppis A is the most detailed ever created Puppis A, the vast, 180-lightyear-wide supernova remnant captured by the Chandra X-Ray Observatory in this picture, was formed after the explosion of a massive star. This false colour image of Puppis A is the most complete X-ray image ever produced of the object and was created using data from the Chandra and XMM/Newton space

observatories, as well as infrared images from the Spitzer Space Telescope. The X-ray elements, shown in blue, are the result of gas heated by the initial shockwave. Infrared emissions are shown in red and green, and are the result of warm dust. The areas where the gas and dust combine appear in bright, pastel hues.

NASA/CXC/IAFE/G.DUBNER ET AL & ESA/XMM-NEWTON

Chandra X-ray Observatory, 10 September 2014

NASA/REID WISEMAN, NASA/ESA, ESO, NASA/ESA/A. ZEZAS (CFA) AND A. FILIPPENKO (UC BERKELEY) ACKNOWLEDGMENT: HUBBLE HERITAGE TEAM (STSCI/AURA) & O. FOX (UNIVERSITY OF CALIFORNIA, BERKELEY)

08

S A room with a view

W Forever young

ASTRONAUT REID WISEMAN INTERNATIONAL SPACE STATION 28 SEPTEMBER 2014

HUBBLE SPACE TELESCOPE 25 SEPTEMBER 2014

“The Milky Way steals the show from Sahara sands that make the Earth glow orange,” wrote Reid Wiseman about the amazing image he was able to capture from his unique perspective 330km above the Earth.

skyatnightmagazine.com 2014

The jumble of stars and gas clouds of varying sizes in this image of dwarf galaxy DDO 68 make it appear not yet fully formed. But astronomers believe its scattered appearance could in fact be the result of a cosmic collision with another star system.

EYE ON THE SKY DECEMBER 09

S Misguided globular EUROPEAN SOUTHERN OBSERVATORY, 10 SEPTEMBER 2014

Buried amid the myriad stars in this image from ESO’s Very Large Telescope is globular cluster M54. It may look the same as many other globulars in our Galaxy, but in reality this glowing celestial gem is an imposter. It actually exists outside of the Milky Way and belongs to the Sagittarius Dwarf Elliptical Galaxy.

A supernova’s secret X HUBBLE SPACE TELESCOPE 10 SEPTEMBER 2014

Look a little closer at this beautiful Hubble image of spiral galaxy M81 and you’ll be able to make out supernova 1993J – it’s located just above the brightest star to the centre-right of the frame. Astronomers have just determined that the supernova has been shielding the glow of a companion star, 21 years after it was first discovered.

skyatnightmagazine.com 2014

BULLETIN DECEMBER 11

Bulletin The latest astronomy and space news written by Hazel Muir

PLUS

CUTTING 14 CHRIS LINTOTT 16 LEWIS DARTNELL

EDGE

Our experts examine the hottest new astronomy research papers The swirling cloud remains over Titan’s southern pole

COMMENT by Chris Lintott

This followed the moon’s seasonal switch from summer to autumn in 2009 – with each season lasting for seven years. “The [spectrum of] light coming from the polar vortex showed a remarkable difference with respect to other portions of Titan’s atmosphere,” says Remco de Kok of Leiden Observatory in the Netherlands, who led the research. “We could clearly see a signature of frozen hydrogen cyanide molecules.” Hydrogen cyanide is present in small amounts throughout Titan’s atmosphere, but it’s the fact that these particles are frozen that is of such interest. Hydrogen cyanide only condenses into frozen particles at temperatures below –148°C, The frozen hydrogen cyanide which is about 100°C colder than models of the signals a change in season moon’s atmospheric temperature had suggested. The cloud is also some 300km above Titan’s surface, where they thought OBSERVATIONS BY NASA’S it would be too warm for clouds Cassini spacecraft have to form. shown that a giant swirling However, infrared cloud over the south pole spectrometry has revealed of Saturn’s moon Titan that Titan’s entire southern is full of frozen particles hemisphere has been cooling of toxic hydrogen cyanide. rapidly, making it possible The discovery suggests for the cloud to form. the atmosphere of Titan’s “This surprising result southern hemisphere is shows how much we’re still cooling much faster than learning about Titan’s weather scientists had expected. and the complex dynamics of its The cloud – actually a swirling vortex several hundred kilometres The vortex is thought to atmosphere,” says Cassini scientist Nicolas Altobelli. wide – was first seen in Cassini be the result of changes in air circulation > See Comment, right images dating back to May 2012.

Toxic cloud hovers over

NASA/JPL-CALTECH/ASI/UNIVERSITY OF ARIZONA/SSI/LEIDEN OBSERVATORY & SRON, NASA/JPL-CALTECH/SPACE SCIENCE INSTITUTE

Titan

I feel a little bit sorry for Titan. It’s had plenty of attention from Cassini, but we are now less than three years from the probe’s fiery plunge into Saturn’s atmosphere. After that, it could be a long wait before anything from Earth visits this enigmatic moon. Yet there are so many good reasons to return and take a proper look at Titan. The seasonal changes deserve studying in depth: understanding the secrets of an atmosphere unlike any other would be a huge boost. The chemistry alone is fascinating, perhaps representing a frozen early Earth. Titan may also be the most interesting astrobiological site in the Solar System, existing on the edge of habitability. Its lakes might host repeating patterns of chemical reactions – nothing as sophisticated as the simplest cell, but the most complex pre-biotic state possible. Being able to understand somewhere like that could advance our knowledge of the origins of life by centuries. CHRIS LINTOTT co-presents The Sky at Night

skyatnightmagazine.com 2014

12

NEWS IN

BRIEF WASP FINDS STRANGE PLANETARY SYSTEM

ESO/L. CALÇADA/NICK RISINGER, COURTESY TMT OBSERVATORY CORPORATION, NASA/JPL-CALTECH/SAO/NOAO, NASA/ESA/D. COE/G. BACON (STSCI), ESO/L. CALÇADA, NASA’S GODDARD SPACE FLIGHT CENTER/S. WIESSINGER, UNIVERSITY OF COLORADO/NASA

A unique star system has been discovered about 600 lightyears away. It’s a binary system in which the two stars each have their own hot Jupiter circling in an extremely close orbit. The planets were identified in a survey by the WASP-South telescopes in South Africa. “This could turn into one of the most important discoveries from WASP-South,” says team member Coel Hellier from Keele University. “The two stars are relatively bright, making it easy to study their planets so WASP-94 could be used to discover the compositions of the atmospheres of exoplanets.”

The high-energy X-rays from the pulsar, shown in magenta, were thought to be the work of a black hole

Amazingly bright

pulsar spotted GIANT TELESCOPE BEGINS SITE CONSTRUCTION Construction has begun on the next-generation Thirty Meter Telescope (TMT) in Hawaii. “This is an exciting moment as we begin construction of the telescope,” says Edward Stone, the TMT’s executive director. “Its giant mirror, nearly 30m across, promises the highest definition views of planets orbiting nearby stars, and the first stars and galaxies in the distant Universe.”

skyatnightmagazine.com 2014

The shrunken, dead star has astounded astronomers ASTRONOMERS HAVE FOUND a pulsar in galaxy M82 that shines with the energy of 10 billion Suns, making it the brightest such object ever found. The pulsar – the collapsed, rapidly spinning remains of a star that has gone supernova – was discovered using NASA’s NuSTAR X-ray observatory. “You might think of this pulsar as the ‘Mighty Mouse’ of stellar remnants,” says NuSTAR scientist Fiona Harrison from the California Institute of Technology in Pasadena. “It has all the power of a black hole, but with much less mass.” The really shocking thing about this discovery is that the source of these X-rays isn’t a black hole. This pulsar is what’s known as an ultraluminous X-ray source, or ULX. Until now, all ULXs were thought to be black holes, which shine brightly in X-rays as matter swirling towards them heats to enormous temperatures. But the observations picked up by NuStar showed that the X-rays coming from this ULX, called M82 X-2, were actually pulsing, something black holes are not known for. M82 X-2 was in fact pulsing every 1.37 seconds, with an energy output around 10 times greater that of other X-ray pulsars.

A pulsar can form when a massive star explodes and its core collapses into a superdense neutron star only about 15km wide. It emits bright radiation from its magnetic poles, and if these beams sweep across the Earth as the neutron star rotates, they appear as regular pulses. As the neutron star’s gravity drags matter from a companion star, it heats up and glows strongly with X-rays. However, the rate of accretion needed to account for a ULX this bright is leaving theorists scratching their heads. Further studies by NASA’s Chandra X-ray Observatory and Swift satellite have confirmed that the intense X-rays come from a pulsar. “Having a diverse array of telescopes in space means that they can help each other out,” says Paul Hertz from NASA’s headquarters in Washington, DC. “When one telescope makes a discovery, others with complementary capabilities can be called in to investigate it at different wavelengths.” Before the association with pulsars was discovered, the unusually bright X-rays of M82 were attributed to medium-sized black holes. www.nasa.gov/nustar

BULLETIN DECEMBER 13

Black holes in surprising places Supermassive monsters may be common even in dwarf galaxies THE SMALLEST GALAXY ever found hosting a supermassive black hole has been discovered by the Hubble Space Telescope and the Gemini Observatory in Hawaii. The finding implies there may be many black holes in the local Universe that have gone unnoticed and could help us understand how these super dense galaxies form. Anil Seth from the University of Utah and colleagues analysed observations of an ‘ultra-

compact dwarf galaxy’ called M60-UCD1 that is only about 300 lightyears wide. They found that it contains a black hole 20 million times as massive as the Sun – that’s five times heavier than the one in our Galaxy. “That is pretty amazing, given that the Milky Way is 500 times larger and more than 1,000 times heavier than M60-UCD1,” says Seth. www.hubblesite.org

Þ Black holes warp light close to their event horizon – which is how astronomers determined its existence

DARK MATTER ESTIMATES FOR MILKY WAY SLASHED DARK MATTER, THE mysterious, unidentified substance thought to make up most of the matter in the Universe, is much less dominant in our Galaxy than astronomers thought. A new study hints there is only about half as much as earlier predictions suggested. Dark matter is invisible to telescopes but astronomers can tell that it’s there due to its gravitational influence on the motions of stars. To measure the amount of dark matter in the Milky Way, a team led by Prajwal Kafle from the University of Western Australia mined data from sky

surveys to measure star speeds up to about 5 million trillion km away. Their results suggest our Galaxy contains 800 billion solar masses of dark matter, much less than previously estimated. This low figure could help explain why there are fewer large satellite galaxies of the Milky Way visible to the naked eye than might be expected. “When you use our measurement of dark matter, theory predicts that there should only be three satellite galaxies out Þ The blue halo represents the there, which is exactly what we see,” says Kafle. expected distribution of dark matter – but there may be less www.uwa.edu.au

NEWS IN

BRIEF MINI STAR STAGES MEGAFLARES Astronomers have detected a series of stellar flares stronger, hotter and longer lasting that ever seen before – and they came from a red dwarf. The first of these eruptions was 10,000 times more powerful than the strongest flare recorded on our Sun. “We used to think major flaring episodes from red dwarfs lasted no more than a day, but Swift detected at least seven powerful eruptions over two weeks,” says Stephen Drake from NASA’s Goddard Space Flight Center in Maryland.

SUCCESS FOR NEW MARS PROBE NASA’s MAVEN spacecraft has beamed back its first observations – including detailed ultraviolet images of tenuous oxygen, hydrogen and carbon in the planet’s atmosphere. MAVEN entered Mars’s orbit on 21 September. “The spacecraft is performing beautifully,” says mission scientist Bruce Jakosky from the University of Colorado. “It really looks as if we’re headed for an exciting mission.”

skyatnightmagazine.com 2014

14

CUTTING Our experts examine the hottest new research

EDGE

Superfast supernova January’s M82 supernova gave scientists a lot to think about – but more data is on its way

shock of the explosion reaches it. With the right geometry, such echoes can appear to expand with superluminal speed. In fact, the apparent breaking of the Universe’s speed limit is the best evidence that these really are light-echoes, and not some other, more pedestrian phenomenon. Echoes like these can reveal the structure of the surrounding material, literally shining a light on the galaxy’s interior – and it’s already clear that surprises lie ahead. The region in which the supernova lies is in the best Hubble images we have, a mottled spread of bright and dark patches. When you look at the image, it seems reasonable to assume that the dark patches are dust lanes. After all, when you look up at the summer Milky Way, the dark rifts that seem to run across Cygnus are places where dust is blocking background light. Thanks to these Hubble observations, we also know that the supernova was buried deep in the galaxy, at least 1,000 or so lightyears behind a major

NASA/ESA/A. GOOBAR (STOCKHOLM UNIVERSITY) AND THE HUBBLE HERITAGE TEAM (STSCI/AURA)

“Perhaps these dark areas are simply places where there is an absence of material”

E

leven and a half million years ago, a star buried in the heart of the starburst galaxy M82 exploded, briefly outshining the rest of the galaxy put together. Its light, which reached Earth in January 2014, was first recognised by astronomers at the University of London observatory. And now a flood of surprising new data is following in the supernova’s wake. A new paper, by Arlin Crotts of Columbia University in New York, reports on exciting new Hubble Space Telescope observations of the supernova, taken in September. They show not the afterglow of the explosion itself, but a faint ring of light – possibly several rings – surrounding the supernova’s position. It would be an enormous coincidence for this structure not to be associated with recent events, but the radius of the most obvious ring is already 36 lightyears across. How can something which happened (from our perspective on Earth) less than a year ago have affected such a large area? The answer is that the rings are a trick of the light – they are, in fact, light-echoes, caused by the material surrounding the exploding star lighting up as the

skyatnightmagazine.com 2014

Þ Supernova 2014J, in the galaxy M32, occurred 11.5 million years ago but wasn’t seen from Earth until January 2014

CHRIS LINTOTT is an astrophysicist and co-presenter of The Sky at Night on BBC TV. He is also the director of the Zooniverse project.

structure – further support for the dust lane hypothesis. And yet when the expanding echo reached one of these dark patches, it didn’t light up. Perhaps there is no obscuring dust after all, and these dark areas are simply places where there is an absence of material. The Herschel Space Observatory found similar holes in the Milky Way; maybe all galaxies are similarly threadbare. The echo is continuing to expand, and by March it will encounter a bright area of nebulosity to the east of the supernova’s position. Beyond that lies another dark patch, which may or may not brighten. Judging by the behaviour of previous nearby supernovae, like that observed in the Large Magellanic Cloud in 1987, we might also see structure as the echoes begin to hit the circumstellar material around the star. Whatever happens, this tiny patch of space will become one of the most studied in the Universe – all because of an explosion that took place before our hominid ancestors walked the Earth.

CHRIS LINTOTT was reading… Light Echoes from Supernova 2014J in M82 by Arlin Crotts Read it online at http://arxiv.org/abs/1409.8671

BULLETIN DECEMBER 15

One of the lumps is reminiscent of an Egyptian pyramid

Cheops is the largest member of a crop of boulders spotted on the lower side of the comet’s larger lobe

ESA’S ROSETTA SPACECRAFT has revealed fascinating boulder-like structures covering the surface of comet 67P/Churyumov-Gerasimenko. One boulder in particular stands out due to its similarity to an Egyptian pyramid – so it has been named Cheops after the largest pyramid within the Giza Necropolis. The strange feature is up to 45m wide and casts a long shadow across the comet’s surface. “The surface of Cheops seems to be very craggy and irregular,” says Rosetta scientist Holger Sierks from the Max Planck Institute for Solar System Research in Germany. His team hopes that as Rosetta continues to circle the comet, it will be able to tell them more about the composition of the boulders and how they might have formed. http://sci.esa.int/rosetta

EXTREME EXOPLANET WOWS SCIENTISTS ASTRONOMERS HAVE MADE the most detailed global ‘weather’ map yet of a planet outside our Solar System, revealing the distribution of water vapour and temperatures in its atmosphere. The gravitationally locked planet, called WASP 43b, is a hot Jupiter orbiting a star 260 lightyears away. Astronomers analysing Hubble observations discovered that it has day side temperatures up to 1,650°C, dropping to 540°C on the night side, while winds howl around the planet at the speed of sound. “The planet is so hot that all the water in its atmosphere is vaporised, rather than condensed into icy clouds like on Jupiter,” says team member Laura Kreidberg of the University of Chicago. www.hubblesite.org

The temperature map of hot Jupiter Wasp 43b – the regions facing the star get hot enough to melt steel

Looking back December 1964

Þ The nebular hypothesis is old, but scientists continue to revise the dates of its events in the present day

On 11 December 1964, The Sky at Night broadcast discussed the origins of the Solar System and asked – how old is the Earth? The widely accepted picture of how the Solar System formed is called the ‘nebular’ hypothesis and was developed back in the 18th Century. It describes how a vast cloud of gas and dust collapsed to form the Sun, with surrounding debris flattening into a disc in which planets,

moons and small bodies such as asteroids formed. But to this day, putting a timeline on these events requires fine tuning. Current estimates put the Sun’s age at 4.57 billion years. The planets formed almost in tandem, with the primordial Earth forming by around 4.5 billion years ago as material in the disc around the young Sun clumped together into small bodies that merged under gravity to build our rocky world.

NEWS IN

BRIEF WATER FOUND ON NEPTUNESIZED PLANET Astronomers have found water vapour on a Neptune-sized planet outside our Solar System for the first time. It’s the smallest exoplanet on which molecules of any kind have been detected. Scientists made the discovery after analysing observations of the planet from NASA’s Hubble, Spitzer and Kepler space telescopes. Its clear, cloudless skies allowed them to identify underlying molecules of water and hydrogen. “This discovery is a significant milepost on the road to eventually analysing the atmospheric composition of smaller, rocky planets more like Earth,” says John Grunsfeld from NASA headquarters in Washington, DC.

EXOMARS SITES SELECTED Four possible landing sites relatively close to Mars’s equator have been selected for the ESARussia ExoMars mission. The two-part mission, planned for launch from 2016, will send an orbiter, stationary lander and rover to search for evidence of Martian life.

skyatnightmagazine.com 2014

ESA/ROSETTA/MPS FOR OSIRIS TEAM MPS/UPD/LAM/IAA/SSO/INTA/UPM/ DASP/IDA, NASA/ESA, ESO, NASA/JPL-CALTECH, ESA/AOES MEDIALAB

Rosetta comet has odd boulders

16 BULLETIN DECEMBER

CUTTING Our experts examine the hottest new research

EDGE

Rapidly rotating spacerocks The fast spin of asteroids can create colossal landslides, transforming them into strange shapes

analysed the resulting mechanics to predict the behaviour of the surface material. Scheeres’ equations showed that once a landslide starts in the mid-latitudes – triggered perhaps by a nearby impact, or even just by the asteroid’s spin-rate accelerating – the granular material can tumble all the way to the equator, piling up on top of itself and accumulating as a bulge around the midriff. This bulge can grow so high that the outermost stuff is above the point at which the gravitational force is strong enough to counterbalance the centripetal force and so hold on to the debris. Instead, it simply lifts off into space. This remodelling process has several consequences. If you see an asteroid with a truncated equatorial bulge you can calculate how rapidly it must have been rotating in the past: the faster the past spin, the less pronounced the equatorial bulge will be, because the top material would have been flung off completely. After loose

“Repeated events can explain how even asteroids can create meteor streams”

THINKSTOCK

R

apidly-spinning asteroids can be strange worlds indeed. Their weak gravitational pull and quick rotation mean that centrifugal forces dominate the behaviour of the loosely-bound crumbly regolith, and this directs the moulding of the asteroid’s whole shape. So just as a mountain on Earth can suffer a landslide if the surface cohesion fails on its steep slopes, spinning asteroids can experience similar movement driven by the centrifugal force, but with the loose rubble skidding and tumbling great distances across the surface. Daniel Scheeres, at the Department of Aerospace Engineering Sciences, University of Colorado Boulder, has investigated this strange scenario and has derived a system of equations that describe all the forces affecting surface grains. His calculations take into account not only the gravitational pull from the asteroidal mass below and the apparent centrifugal force from the body’s spin, but also the weight of material on top and the frictional forces between neighbouring grains. To keep the mathematics simpler he considered only roughly spherical objects, which isn’t in fact a bad approximation for many asteroids, and then

skyatnightmagazine.com 2014

The shape of an asteroid can tell us a great deal about its history, such as how its rate of spin has changed over time

LEWIS DARTNELL is an astrobiologist at University of Leicester and the author of The Knowledge: How to Rebuild our World from Scratch (www.theknowledge.org)

rubble has slumped around the face of the asteroid the remaining material will have a stable slope angle. If this has occurred you’d expect to see a constant surface slope over a large range of mid-latitudes. And asteroids have already been found with exactly these quirky features. For example, 1999 KW4 Alpha spins very rapidly – every 2.76 hours – and displays exactly the expected bulging midriff. And just as predicted by the equations, the midlatitudes around the asteroid show a constant slope angle of about 40° – the tell-tale artifact of past global landslides. This weird behaviour also neatly explains odd cases like P/2013 P5, which was originally thought to be a comet due to the coma-like cloud of debris streaming off it, but which was later realised to be composed of asteroidal dust. Repeated spinning-up and debrisshedding events can explain how even asteroids can create meteor streams.

LEWIS DARTNELL was reading… Landslides and Mass Shedding on Spinning Spheroidal Asteroids by D J Scheeres Read it online at http://arxiv.org/abs/1409.4015

Telescopes Direct For all your Astronomy needs Merry Christmas from Telescopes Direct! We stock a very large range of telescopes, mounts, accessories, imaging equipment, solar products & more. Whatever your level, we have the best equipment and prices!

Question? Email [email protected]

NEW NexStar Evolution is Available Now!.... ....6”....8”....9.25”

The best yet from Lunt?

rs u o y der ! r o Pre now

New Lunt 50mm Solar Scope!

New to Telescopes Direct... The Original -And (DFK¿OWHUJXDUDQWHHG\HDUV The Best! Now only £295.00!

A new benchmark in portable imaging...

NEW SKY-WATCHER STAR ADVENTURER ASTRO-IMAGING MOUNT

From £219.00

www.telescopes-direct.com

WHAT’S ON DECEMBER 19

What’s on

Our pick of the best events from around the UK

PICK OF THE MONTH

The Royal Observatory Greenwich Christmas Lecture Royal Observatory Greenwich, London, 19 December, 7pm

Asteroids: A Planetary Risk or a Valuable Resource? Stirling Astronomical Society, Smith Museum and Art Gallery, Stirling, 12 December, 7.30pm This month, Stirling Astronomical Society will host the University of Glasgow’s Dr Matteo Ceriotti, who will be discussing the case for asteroids. Should we be considering them a threat or a massive, untapped resource? Entry is free to all. www.stirlingastronomicalsociety.org.uk

The Cosmic Comic Revisited Ellingham Recreation Centre, Great Ellingham, Norfolk, 12 December, 7.30pm Breckland Astronomical Society welcomes Andrew Briggs to host its Christmas lecture, The Cosmic Comic Revisited. Briggs will address some of the most up to date astronomy topics in the form of comic strip illustrations, taking a light-hearted look at some difficult cosmic concepts. www.brecklandastro.org.uk The event will take place within the Observatory’s planetarium

©NATIONAL MARITIME MUSEUM/LONDON, ESO, NASA/JPL-CALTECH, THINKSTOCK

We may be in the depths of winter, but take a trip to the Royal Observatory Greenwich in London for its annual Christmas lecture on the 19th and the subject matter is sure to warm you up. This year, solar physicist and Sky at Night presenter Dr Lucie Green will be discussing the most up to date research on the Sun as well as exploring the history of solar observing at Greenwich.

She’ll also be looking ahead to 2015 with a space weather forecast. There’s no need to arrive with a vast knowledge of the cosmos, as this accessible lecture will be suitable for all – children included. Tickets to the lecture cost £7 per person and are available to buy online. www.rmg.co.uk/visit/events/rogchristmas-lecture

BEHIND THE SCENES

The Antikythera Mechanism William Hulme’s Grammar School, Manchester, 8 December, 7pm Michael Edmunds, emeritus professor of astrophysics at Cardiff University, travels to West Didsbury Astronomical Society to deliver a talk on the famous Antikythera Mechanism, an analog computer that predicts the movements of the heavens and dates back to between 150 and 100 BC. The event is free to members, visitors are welcome. www.wdas2.com

THE SKY AT NIGHT IN DECEMBER Four, 14 December, 10pm (first repeat

Four, 18 December, 7.30pm)*

PILLARS OF CREATION: THE SKY AT NIGHT Perhaps no objects in the night sky conjure a greater sense of awe than nebulae. These vast clouds of dust and gas play a key role in star birth and death, and therefore in our own origins. And driving their creation is a kind of chemistry that the textbooks say shouldn’t be happening. The Pillars of Creation within M16 are one *Check www.bbc.co.uk/skyatnight of the most iconic sights in the night sky for subsequent repeat times

MORE LISTINGS ONLINE Visit our website at www. skyatnightmagazine.com/ whats-on for the full list of this month’s events from around the country. To ensure that your talks, observing evenings and star parties are included, please submit your event by filling in the submission form at the bottom of the page.

skyatnightmagazine.com 2014

A PASSION FOR SPACE DECEMBER 21

A PASSION FOR

with Maggie Aderin-Pocock

The Sky at Night presenter considers the perils of launching a lander down to the surface of a comet

ESA/ATG MEDIALAB

A

fter 10 years of planning and nearly 11 years of travelling through space, its nearly time for Rosetta to launch its Philae lander down to comet 67/PChuryumovGerasimenko. The culmination of this epic journey is likely to result in much collective nail-biting and breath-holding from the scientists involved in the project. Philae makes it perilous plunge to the comet’s surface on 12 November, unaided by rockets or thrusters. This uncontrolled flight, covering 20km, is estimated to last an agonising seven hours before making contact. Although comet 67/PChuryumovGerasimenko is the size of Mont Blanc and weighs 10 billion tonnes, it is much smaller than your average planet and so has very low gravity. This means that contact is unlikely to be very violent, as we have seen with rover landings on Mars. However, due to this low gravitational pull the lander could easily bounce off, so it is equipped with ice screws and harpoons to keep it in place. The Rosetta spacecraft has been in orbit around the comet for the past three months, analysing emissions from the icy visitor as it gets warmed by the Sun and

a comet’s nucleus. This is an amazing feat, considering that on approach the spacecraft was travelling at a relative velocity of over 750m/s and reduced this to a mere 1m/s over a period of four months. The instruments on board the Rosetta orbiter have already started acquiring data and show that the comet reflects little ultraviolet light. Initial measurements indicated that the comet was losing around one-third of a litre of water per second; this is now up to five litres per second and will increase to a few tonnes per second as it approaches its closest point to the sun. There will be a lot more to see as the orbiter and comet loop around the Sun. So successful deployment of the lander would definitely be the icing on the cake, but 80 per cent of the mission’s objectives can still be obtained even if the lander fails. I feel honoured to be present at mission control in Germany on the 12th, reporting for The Sky at Night as the lander makes the daring trip and the first data comes in. I think my biggest challenge may be remembering to breathe. S > For more on Rosetta, turn to page 62

Philae’s feet contain ice screws to help secure it to the comet’s surface

mapping the surface to select a suitable landing site for Philae. But there are still a lot of critical unknowns. for instance, a number of boulders have been spotted on the surface and if the lander hits one of these it could be disastrous. Nor do we know much about the material properties of the surface. When the lander is in place this will be just the sort of data it will be able to collect with its onboard instruments, but in the meantime it will be descending to an unknown surface.

It’s not all on Philae Though this part of the mission sounds daunting, it is important to put it into context. The Rosetta mission is already considered a resounding success, being the first spacecraft to enter orbit around

Maggie Aderin-Pocock is a space scientist and co-presenter of The Sky at Night skyatnightmagazine.com 2014

EXOPLANET EXCURSIONS DECEMBER 23

JON CULSHAW’S

EX PLANET EXCURSIONS

MAIN ILLUSTRATION BY MARK GARLICK, PHOTO: EMMA SAMMS

Jon journeys to one of Pluto’s compatriots, a dwarf planet in our own Kuiper Belt Having pushed the Cruiser Globe to its limits recently, I’m mindful to stay more local this excursion. So a fascinating and relatively unknown area of our Solar System beckons – the Kuiper Belt, situated a mere 4.5 billion km from the Sun. I’ve fond memories of the Kuiper Belt after causing hearty laughs in a 1980 geography class by misspelling it as ‘the Kipper Belt’. The Kuiper Belt is symbolised in my mind by the summer that a big barn was built at my Uncle Richard’s mushroom farm. Once completed, there was a zone circling 20m around the barn composed of scattered concrete, metal bolts and lumps of wood, all left over from the barn’s construction. The Kuiper Belt is our Solar System’s version of this outer debris zone – all the cast-out fragments of its formation. Here’s where we find the eerie conglomeration of the dwarf planets, those trans-Neptunian objects floating around as if occupying a cosmically huge lava lamp. The Kuiper Belt has a most alien feeling while being tantalisingly

close. Evocative of a hidden alleyway between the shed and Victorian coal house in your grandparents’ garden. Spooky, dark and unnerving but full of curious objects and deliciously close by, ready to fire the imagination of inquisitive minds. The dwarf planets are generally Pluto-sized and although the IAU have designated only five officially, it’s believed there could be many thousands of them. One such dwarf world has a name like a holiday camp rapper, ‘MakeMake’ (pronounced ‘MarkayMarkay’). This curious lump is 710km in diameter, taking 310 years to complete one orbit. From the Cruiser Globe, the cratered, pitted surface below looks like a coral ornament on a fish-tank floor. Its surface of frozen nitrogen and methane gives off a pale terracotta hue. MakeMake’s orbit could presently be at its closest to the Sun as a little of the nitrogen and methane surface ice seems to be gently vaporising, creating a temporary, delicately thin atmosphere. Against the jet-black sky from this distance, our Sun still shines

with an arresting brightness, like an LED placed at the far end of an aircraft hangar. Piercingly luminous, it’s reassuring how the Sun punches above its weight from 50 AU away. It’s easy to imagine this world being mined for its resources by aggressively industrial humans in the far future. Calm and silence reigns for now, as does a charmingly alien sight. A collision between two objects around the size of Rosetta’s target comet has resulted in a cloud of fragments, each around the size of a Routemaster bus. It resembles the close-up images of Saturn’s rings, with individual boulder chunks appearing to unite as a swarm of jagged crescent Moons, and the release of icy material produces a rainbow effect like patches of multicoloured nebulosity. It’s pleasing to know our Kuiper Belt can serve up the most profoundly alien views equivalent to the most jaw dropping in the Universe. Jon Culshaw is a comedian, impressionist and guest on The Sky at Night

24

This month’s top prize: four Philip’s books The ‘Message of the Month’ writer will receive four top titles courtesy of astronomy publisher Philip’s. Heather Couper and Nigel Henbest’s Stargazing 2014 is a month-by-month guide to the year and you’ll be able to find all the best sights with Patrick Moore’s The Night Sky. Stargazing with Binoculars by Robin Scagell and David Frydman contains equipment and observing guides, and you’ll be viewing planets, galaxies and more with Storm Dunlop’s Practical Astronomy.

Interactive EMAILS • LETTERS • TWEETS • FACEBOOK Email us at [email protected]

MESSAGE OF THE MONTH Astro imaging, the six-year-old way

Þ Winter evenings are an opportunity to introduce young minds to the wonders of the night sky, says Nick Cox My eldest granddaughter, aged six, was over for the weekend. As it got dark early, we went out to see the stars before the Moon came up. As I showed her the Great Square of Pegasus, the Summer Triangle and the Northern Cross, we saw the ISS halfway through its early pass and watched it set in the east. Katie was so excited to see it, and asked what they did up there! Then I pointed out the W of Cassiopeia, explaining that is what our Sun would look like from there. “We have a dull little star,” was Katie’s reply. I pointed out the constant light of a satellite passing under Cassiopeia. Mrs C then joined us and we saw the Double Cluster and M31, firstly by eye, then through an old pair of 8x30 binoculars. I skyatnightmagazine.com 2014

showed her where the chain of stars that make up Kemble’s Cascade ran, one top width of Cassiopeia to the left, and we spotted the Coathanger asterism in Brocci’s Cluster by continuing the line from Altair to Tarazed. To top the evening off we found Uranus just above the conifer at the top of the garden. Katie drew a picture of the ISS and will write up a page of her findings for school. So now the evenings are drawing in, wrap up the wee ones and take them outside to look up! Nick Cox, Derbyshire

We clearly have a budding astronomer in our midst! Thanks for sharing with us Nick. – Ed

LETTERS DECEMBER 25

SOCIAL MEDIA WHAT YOU’VE BEEN SAYING ON TWITTER AND FACEBOOK Have your say at twitter. com/skyatnightmag and facebook.com/ skyatnightmagazine @skyatnightmag asked: Which space mission are you most looking forward to in 2015?

Northern lights

Every day’s a school day

Living in light-polluted Manchester, I couldn’t miss out on imaging the Milky Way during a weekend to Reeth in the Yorkshire Dales for my 40th birthday this summer. I walked half a mile to the north of the village in an attempt to avoid light pollution and captured this image of the Milky Way. I was successful but the sky glow, even from such a small village as Reeth, is prominent in the image.

Thank you for your piece ‘Opening the Classroom’ in your August issue (page 40). I’ve completed Astronomy: Discovering the Universe from Open2Study. I’m pleased with a 93 per cent score and found the course informative and enjoyable, with the bonus that it didn’t eat into too much of my spare time. I’d recommend it, especially if you want to start learning more about radio astronomy.

Dave Hornby, Manchester

Chris Abrahams, Exeter

Light pollution is an ever-growing burden Dave, but you’ve managed to create a very atmospheric image by working it into the picture. – Ed

We’re glad to have inspired you to take your passion for astronomy further, Chris. – Ed

Michael Stewart: Got to be New Horizons. First close up view of Pluto. @sjb_astro It’s got to be New Horizons’ flyby of Pluto. At long last we’ll get a close look at this enigmatic world. @Johnimus_Prime Tim Peake’s trip to the ISS will hopefully be a huge inspiration to everyone and raise the profile of the UK’s space industry. David Galbraith: New Horizons! It’s going to be a very interesting year in space, but you only get a first look at a body as important as Pluto (planet or not!) once. @Keaton_S @astro_ timpeake’s launch! What else comes close to a true bona fide British astronaut in space at long last?! HUGE moment! Ed Gallagher: The only one of interest for 2015 should be New Horizons. I’ve been waiting since it launched to find out what Pluto actually looks like. John Hugill: Dawn, because the techniques used on this mission could be used in planetary defence! Not just very interesting but very useful. Julia Wilkinson: Has to be a shout out for Tim Peake when he becomes the first British astronaut to visit the ISS.

Þ Dave Hornby’s picture shows how much of a problem light pollution can be, even in rural areas

Clouding the issue In your excellent article about how NASA plans to protect its Mars orbiters from an encounter with comet C/2013 A1 Siding Spring (November 2014, page 38), mention is made of the comet’s origin in the Oort cloud. Not that I am doubting it, but what hard evidence is there for the existence of the Oort cloud? Is it just theoretical or has any part of it been observed or detected in some other way? Finally, presumably Voyagers 1 and 2 will not arrive in its vicinity for a long, long time – well after their internal power sources have been exhausted – so sadly I suppose no data can be expected to be received from either of them. David Tart, Birmingham

To date there have been no direct observations of the Oort cloud, but it is possible that the Kepler Space Telescope may be able to detect a handful of objects. Even if it doesn’t find anything, it is still possible that the Oort cloud could exist, but is simply less densely packed than we thought. – Elizabeth Pearson, staff writer

Another early starter I am new to this hobby and bought a telescope for my six-year-old son (Harry) as he came top of his class and won an achievement award at school. I explained to him that he could have a toy if he wanted, or I would spend a little more money if he wanted something educational. He asked to think about it and a couple of days later asked if he could have a telescope. My wallet is now a little bit lighter but a deal is a deal, so I bought him a Celestron 127 SLT. Our first few attempts at stargazing have been great adventures, but we have seen little in the sky. On our first attempt I got the car stuck in a field (big thanks to the farmer who got us out at midnight) and we saw nothing. On the second attempt, we got the scope set up but my little boy struggled to see through the eyepiece. I then figured out how to attach our DSLR to the scope so that Harry could see on the laptop screen. And on the third attempt, we set the scope up and captured the picture below. Obviously my little boy is now hooked and woke up at 4am the next morning to see Jupiter. John Clare, via email

Any six-year-old who chooses a telescope over an Action Man is destined for great things! – Ed A great Moon shot pays persistence off

......................................................................................... OOPS! • In last month’s issue of BBC Sky at Night Magazine we incorrectly stated in our feature ‘The Dark Isle’ that the Isle of Man is the fourth most likely nation to launch the next mission to the Moon. In fact, the island is the fifth most likely nation after the US, Russia, China and India. • One of the extra Hotshots images featured on last month’s coverdisc was incorrectly attributed to Dr Grant Mackintosh. In fact the image was taken by his nephew, 11-year-old Foster Parker Stimpson.

skyatnightmagazine.com 2014

Sky at Night MAGAZINE

SAVE WHEN YOU SUBSCRIBE

TO THE DIGITAL EDITION

Available from

The perfect addition to your stargazing, BBC Sky at Night Magazine is your practical guide to astronomy, helping you to discover the night skies, understand the Universe around us and learn exciting techniques for using your telescope.

Enjoy our Premium App experience now available from

Sky at Night MAGAZINE

28

Hotshots

This month’s pick of your very best astrophotos

PHOTO OF THE MONTH

S M31, the Andromeda Galaxy GAVIN JAMES, MARLBOROUGH, 27 SEPTEMBER 2014 Gavin says: “I love the subtle detail that the mono camera captures compared to a DSLR. I opted for a sub-exposure length of 10 minutes for the luminance channel, hoping to pick up the contrast in the dust lanes. For the core itself I used a set of sub-exposures of just two minutes and blended the images together in Photoshop, adding colour with sets of 10-minute exposures in each of the red, green and blue channels. Finally, the hydrogenalpha star-forming regions surrounding the galaxy, which pop out in the pink-red colour,

skyatnightmagazine.com 2014

were captured with an Ha filter and exposures of 20 minutes. In total there are over 14 hours’ worth of exposure time in this image!” Equipment: QSI 683-WSG monochrome CCD camera, Sky-Watcher Evostar 80ED DS-Pro telescope, Sky-Watcher HEQ5 Pro mount. BBC Sky at Night Magazine says: “It’s the clarity and definition in this image of the Andromeda Galaxy that really stood out to us. Gavin has managed to define so many

aspects of the galaxy, from the dust lanes to Andromeda’s glowing heart, with expert skill.” About Gavin: “I first started taking photos through a telescope in my back garden just over a year ago. My first target was M31 and the results amazed me, even though the image wasn’t that good. A year on, with better equipment and much more experience, this is my fourth attempt at M31, and I’m finally happy with the image.“

HOTSHOTS DECEMBER 29

S Sadr region

W Super Moon

PETER MARTIN IRELAND 19 AUGUST 2014

MICHAEL LAMONACO NEW JERSEY 9 SEPTEMBER 2014

Peter says: “The amount of nebulosity that surrounds Sadr makes it one of the best regions to image in the northern summer sky.“

Michael says: “This image shows the Harvest Moon – this year’s finale of supermoons.“ Equipment: Canon EOS 60Da DSLR camera, 75-300mm lens.

Equipment: Starlight Express H694 CCD camera, William Optics GT-81 telescope.

NGC 281 X

S M33 SCOTT FINDLAY, FRANCE, 5 SEPTEMBER 2014 Scott says: “The addition of hydrogen-alpha helps to highlight some of the more interesting areas of M33, as well as bringing out some of the faint nebulosity just to the right of NGC 588 in the image.“

CHRIS HEAPY MACCLESFIELD 9 SEPTEMBER 2014 Chris says: “Taken under the poor conditions of a full Harvest Moon, this was a good test for my new 3nm narrowband filters. I particularly like the colours and contrast these filters produce – the teal blue OIII really stands out.“ Equipment: Atik 490EX CCD camera, TeleVue NP127is refractor, Losmandy G11 mount.

Equipment: FLI Microline ML8300 CCD camera, 12-inch ASA Newtonian telescope, ASA DDM85 mount.

skyatnightmagazine.com 2014

30 HOTSHOTS DECEMBER

Omega Centauri X PABLO VERA TIZNADO SANTIAGO, CHILE, DATE UNSUPPLIED Pablo says: “This globular cluster is about 16,000 lightyears from Earth. It is the brightest globular in the sky, contains about 10 million stars and has a diameter of roughly 150 lightyears. The stars in the core are estimated to be, on average, only 0.1 lightyears away from each other.“ Equipment: Canon EOS Rebel T3i DSLR camera, Orion 8-inch f/3.9 Newtonian reflector, Celestron CG-5GT EQ mount.

S The Sun

The Dumbell Nebula X

RICHARD JENKINSON CHESHAM, 31 AUGUST 2014

STEPHEN GILL YORKSHIRE, 20 SEPTEMBER 2014

Richard says: “While viewing the Sun through my PST I saw this huge filament, which looks to be continuous for about one-fifth of its width.” Equipment: Sony A65V DSLR camera, PST solar telescope.

Stephen says: “This image was created using five separate one-minute exposures taken at an ISO of 1600.” Equipment: Modified Canon 600D DSLR camera, Celestron C11 telescope.

W Sagittarius region TERRY HANCOCK MICHIGAN, SEPTEMBER 2014 Terry says: “This four-panel Hubble palette mosaic will be my last addition to this area until 2015. It covers an area of sky equal to 4º by 7º.” Equipment: QHY11 monochrome CCD camera, Takahashi E-180 telescope, Paramount GT-1100S equatorial mount.

ENTER TO WIN A PRIZE! WORTH

£99

skyatnightmagazine.com 2014

We’ve teamed up with the Widescreen Centre to offer the winner of next month’s best Hotshots image a fantastic prize. The winner will receive an Orion StarShoot Solar System Colour Imager IV camera, designed for capturing sharp shots of the Moon and planets. www.widescreen-centre.co.uk • 020 7935 2580

Email your pictures to us at [email protected] or enter online.

THE ADVENT CALENDAR

OBSERVING13 CHALLENGE Get in the Christmas spirit with our guide to the festive season’s most fabled celestial sights o doubt many will recall the pleasures of receiving an Advent calendar at the beginning of December as part of the build-up to the Christmas festivities. Each new day, we opened a window on the calendar to expose another Christmas picture or, in more recent times, another chocolate! This month’s observing challenge is aimed at rekindling that sense of anticipation and wonderment, as we recommend 24 of the best pre-Christmas

THINKSTOCK X 5, STEVE MARSH X 2

N

celestial sights. The Moon will be making its presence very well known during the first half of our challenge, with full Moon occurring on 6 December. With this in mind, it seems only sensible to take full advantage and explore the lunar surface in some detail. December also sees two meteor showers, a well-placed shadow transit and an opportunity to enjoy some wonderful deep sky treats. So wrap up warm, have a hot drink handy and see what’s behind the first window. >

1 18

2

13

7

16

21 5 11

22 3

34

1 to 12 December THE MOON AND PLANETS

4 10

With Pete Lawrence

3

With the Moon high and moving through its brightest phases over the first 12 days of Advent, it’s an ideal time to revel in the illuminated peaks, shadowed valleys and cratered maria of the lunar landscape.

6 8

7

1

9

ABOUT THE WRITER Pete Lawrence is an astrophotographer who has written several books and appears regularly on The Sky at Night and Stargazing LIVE.

11

Lunar features locator X

1

COPERNICUS X

3

SCHRÖTER’S VALLEY

2

THINKSTOCK X 2, STEVE MARSH X 5, PETE LAWRENCE X 3

The bright crater Aristarchus (40km) is close to the terminator on tonight’s gibbous Moon. Herodotus (35km) is the darker crater on the terminator side of Aristarchus. Just north of the pair is Schröter’s Valley, tonight’s Advent target. At 160km in length, this is the largest example of a sinuous rille on the Moon. � SEEN IT

skyatnightmagazine.com 2014

URANUS

Uranus is in Pisces, 3.25° south of mag. +4.0 Delta (b) Piscium. At mag. +5.8, the planet is an easy spot in binoculars. A telescope will show its tiny greenish disc. You can find Uranus 20 arcminutes south of the Moon’s southern limb at 00:30 UT. � SEEN IT

Crater Copernicus (93km) is visible close to the mid-point of the terminator on tonight’s gibbous Moon. It sits at the heart of a huge system of bright rays that spread across the lunar surface for hundreds of kilometres. The crater has a distinctive terraced rim and an impressive central mountain complex, the peaks of which tower 1,200m above the floor below. Those with larger scopes may notice the crater floor appears smoother in the north. � SEEN IT

4

PYTHAGORAS X

At 129km across, you’d think crater Pythagoras would be hard to miss. But, sitting close to the northwest limb, it’s foreshortened into a narrow ellipse and this can make it slightly trickier to pick out from its surroundings. It’s a fine crater though, and well worth hunting down just to see its lovely 1.5km-high central peak. � SEEN IT

ADVENT CHALLENGE DECEMBER 35

5

JUPITER AND ITS MOONS

Jupiter can currently be seen rising in the east-northeast around 22:00 UT – an easy catch if you have clear weather. Look at the planet through a telescope in the run-up to midnight on 4 December and the four Galilean moons will be strung out like a line of pearls to the east. As an added treat Callisto, the second moon out, will be casting its shadow centrally on the planet at 00:00 UT on 5 December. � SEEN IT

Europa Io

Ganymede

Callisto Callisto's shadow

7

REINER GAMMA

9

MARE TRANQUILLITATIS

Relief features have height, becoming visible when they cast shadows; albedo features are those that are visible because of their reflectiveness. Reiner Gamma is an eye-shaped albedo feature located west of crater Reiner (30km) in the Oceanus Procellarum. Two ribbons of lighter material can be seen winding west and northeast of the ‘eye’. � SEEN IT

8

11

The Rupes Altai define the western boundary of the Nectaris Basin. Formerly known as the Altai Scarp (and before that, the Altai mountains), they will be casting dramatic shadows tonight. Look out for the large arc they make close to the terminator in the southeast lunar quadrant. The dramatic crater Theophilis (100km) is also visible inside the arc, close to the terminator. � SEEN IT

Tonight’s full Moon means that few shadows will be visible. Located in the Mare Serenitatis is a small and rather curious bright patch associated with the crater Linne. It lies southeast of where the Mare Serenitatis joins the Imbrium Basin, a region framed by a gap between the Appenine and Caucasus mountain ranges. Linne itself is rather small at 2.4km across. Its circular bowl shape is easiest to see when obliquely lit, but around full Moon all that’s really visible is its enlarged circle of ejecta. In 1866, this double identity led to an observation stating that Linne itself had changed in appearance. � SEEN IT

MARE CRISIUM

Mare Crisium (620x570km) is one of the most distinctive features on the Moon. Located close to the eastern limb, its shape is foreshortened and from Earth it’s clearly visible to the naked eye as a dark oval patch. Unlike the other seas, Mare Crisium is completely detached. Its dark, smooth-looking floor has a higher boundary which shows fantastic shadows as the terminator approaches and crosses the mare. Bright rays from crater Proclus (28km) mark the surface from the west. � SEEN IT

10

The 700km Mare Tranquillitatis is an impact basin formed when a large object slammed into the Moon, causing a depression. Cracks in the impacted surface allowed lava to flow through, which eventually filled the basin, and when this cooled it gave the mare a dark, relatively smooth appearance. The Mare Tranquillitatis is joined to the Mare Serenitatis to the northwest; through a telescope, it’s interesting to note the boundary where the darker lava of Tranquillitatis contrasts against the lighter, younger lava of Serenitatis. � SEEN IT

RUPES ALTAI

6

CRATER LINNE

BURG AND LACUS MORTIS

Lunar crater Burg (40km) lies to the west of Hercules (70km), located near to tonight’s terminator in the northeast quadrant. Burg has distinctive high terraced walls and a prominent central mountain peak. It sits inside a 150km lava-filled hexagon worryingly known as Lacus Mortis, or the Lake of Death. � SEEN IT

Mars

VENUS OR MARS

12

Venus is extremely bright, but its position close to the Sun sometimes makes it hard to spot. It has been a morning object for much of 2014, but it is now slowly emerging from behind the Sun in the evening sky. Wait for the Sun to properly set and see if you can spot it very low in the southwest; Venus currently sets about 40 minutes after the Sun, so you don’t have long! Keep watching this part of the sky as darkness falls, and see if you can locate dimmer and distinctly orange Mars. The two planets are set to have a really close encounter at the end of February 2015. � SEEN IT Venus

Relative positions of Venus and Mars shortly after sunset on 12 December; Mars will not be visible until Venus has set, by which time it will have moved further to the west

SW

skyatnightmagazine.com 2014

36

13 to 24 December DEEP SKY

NGC 1514

18 M36 M37

With Steve Richards With our lunar observations completed and the Moon on the wane, it’s time to move on to observe a wider range of celestial objects – and to take a closer look at some very familiar sights.

Castor

13

Geminids Peak 13/14 Dec

M35

Pollux

Pleiades

17Hyades

NGC 1746

15

16 NGC 2129

Collinder 89

`

20

Elnath

`

GEMINI

_

19

AURIGA

b

NGC 1647

M1

_ Aldebaran

Berkeley 21

TAURUS a

NGC 1807

b

14 NGC 2392

Collinder 65

ABOUT THE WRITER Steve Richards is a keen astro imager and astronomy equipment expert who specialises in deep-sky observing.

a

Alhena

NGC 2169

NGC 1662

ORION Collinder 69

Chrismas Tree Cluster/Nebula

CANIS MINOR Procyon

a

_ Betelgeuse

Bellatrix

NGC 2236 Collinder 111 Collinder 106 Collinder 107

`

Rosette Nebula NGC 2244

NGC 2071 M78

Collinder 91

_

23 b Collinder 70

NGC 2301 M43 NGC 1980

b NGC 2232

`

NGC 1981 M42

ERIDANUS

21

` Rigel

a `

MONOCEROS M50 M48

NGC 2353

M47 M46

NGC 2360

13

THINKSTOCK X 6, ALAMY X 2, CHART BY PETE LAWRENCE

15

skyatnightmagazine.com 2014

b

` M79

THE ESKIMO NEBULA

The Eskimo Nebula is perfect for a winter observing session and can be found by scanning 2.4° east-southeast of mag. +3.5 Wasat (Delta (b) Geminorum). With a diameter of only 15 arcseconds, the ‘face’ and ‘furry hood’ of this beautiful planetary nebula are best seen through a 6-inch telescope or larger. � SEEN IT

We start this section within the Solar System. The Geminid meteor shower is one of the year’s most intense, with a zenithal hourly rate of around 120. Unusually, the shower doesn’t originate from a comet but is debris from asteroid 3200 Phaethon. Meteor activity takes place from 4 to 17 December, but peaks around the 13th and 14th. This year’s shower coincides with a last quarter Moon that rises just before 23:30 UT, so get out early in the evening. � SEEN IT

Lying 1.5° northeast of mag. +3.3 Propus (Eta (d) Geminorum), M35 is a sparkling open cluster. From a dark site it’s faintly visible to the naked eye, but a 4-inch telescope will reveal numerous stars. The brighter stars are fairly evenly distributed and the central star stands out as being particularly orange. � SEEN IT

`

14

THE GEMINID METEOR SHOWER X

M35

_

_

NGC 2423 NGC 2539

CANIS MAJOR

24 Sirius

Melotte 71

Deep-sky objects locator X

LEPUS

NGC 2235 NGC 2343

_

16

THE CRAB NEBULA X

Lying just 1° to the north west of mag. +3.0 Zeta (c) Tauri is the remnant of a star that went supernova in 1054 and, according to Chinese astronomers, shone four times brighter than Venus. Nearly 1,000 years later its shape, as seen through a 10-inch or larger telescope, has provided its common name of the Crab Nebula. Thanks to its relatively high surface brightness, 6-inch and larger telescopes show a hazy grey patch of nebulosity. � SEEN IT

ADVENT CHALLENGE DECEMBER 37

17

18

THE HYADES

Mag. +0.9 Aldebaran (Alpha (_) Tauri) calls us like a beacon to our next object, the Hyades star cluster. Marking the bull’s head in Taurus, the Hyades are a wonderful sight though binoculars – the main stars forming a V shape with Aldebaran lying at its bottom left corner. � SEEN IT

19

CALIFORNIA NEBULA

Lying just 1º north-northeast of mag. +4.0 Menkib (Xi (j) Persei) is the California Nebula. It was discovered in 1885 using the 6-inch Cook refractor at Vanderbilt University in Tennesse, and you too can observe this wonderful emission nebula using low magnification and a 6- to 8-inch telescope. Although this vast cloud of hydrogen gas is a favourite with CCD imagers using long exposures to capture the nebulosity, you’ll need an ultra-high contrast or hydrogen-beta filter to observe the fine detail. � SEEN IT

21

THE ORION NEBULA

To be this close to Orion yet not visit the Orion Nebula would seem strange! This stunning nebula is one of the showpiece objects of the winter sky and represents the ‘sword’ hanging from the Hunter’s belt. Any size of telescope or binoculars will show something of interest in this fascinating and bright object. � SEEN IT

23

COLLINDER 70 X

Our penultimate object is such a popular naked-eye sight that it may never have occurred to you that it is actually an open cluster, comprising in excess of 100 stars in an area roughly 3° across. The three bright stars Alnitak, Alnilam and Mintaka (known as ‘The Three Kings’ in some cultures) that together make up the ‘belt’ stars of Orion are in fact the core of the cluster catalogued as Collinder 70. � SEEN IT

THE CRYSTAL BALL NEBULA

This one is a challenge in a small telescope so try hunting it down with an 8- to 10-inch instrument. The elusive Crystal Ball Nebula lies about four-fifths of the way along a line drawn between mag. +1.7 Elnath (Beta (`) Tauri) and mag. +2.8 Zeta (c) Persei. Identifying ts central star and then scrutinising the view using an OIII filter will show the slightly oval-shaped surrounding halo of this attractive planetary nebula. � SEEN IT

20

THE PLEIADES

Tonight’s object is very easy to spot but is no less beautiful for that. Binoculars are the best way to enjoy this wonderful cluster in Taurus, although you’ll find it easily enough with the naked eye to the northwest of mag. +0.9 Aldebaran (Alpha (_) Tauri). The shape produced by the brighter stars is reminiscent of the bowl of the Plough asterism. � SEEN IT

22

THE URSID METEOR SHOWER Although nowhere near as strong as the Geminids, this year’s Ursid meteor shower conveniently coincides with a new Moon, offering the best possible conditions for observation. It has a zenithal hourly rate of 10 meteors per hour. Look between midnight and dawn – the meteors, as the name suggests, will appear to radiate from the direction of the constellation of Ursa Minor. � SEEN IT

24

SIRIUS

Follow a line from mag. +2.4 Mintaka (Delta (b) Orionis) through the other two ‘Kings’ to bring you to the brilliant mag. –1.5 Sirius (Alpha (_) Canis Majoris). Could this, the brightest star in the night sky, be the star that the Three Kings were following? A binary star with a faint companion, Sirius appears to flash red, white and blue but this is just a trick of the light, caused by refraction through the atmosphere. � SEEN IT S

skyatnightmagazine.com 2014

ESO/L. CALÇADA, ALAMY, NASA AMES/SETI INSTITUTE/JPL-CALTECH, THINKSTOCK X 7

THE

REBIRTH OF

Kepler

NASA’s flagship exoplanet hunter is on a new mission. Will Gater investigates

KEPLER’S K2 MISSION DECEMBER 39

I

f there’s one thing that’s guaranteed to make the blood of any space explorer run cold, it’s the thought of losing control of their craft out in the depths of space. Plenty of sci-fi adventurers have met their end this way, drifting silently through the vacuum, but for one mission – NASA’s Kepler space telescope – that worry became all too real last year. Kepler had been launched four years earlier and was designed to be the US space agency’s flagship mission for hunting exoplanets. Its task sounds simple on paper: to stare patiently, hawk-like, at roughly 150,000 stars in a single patch of sky between the bright stars Deneb in Cygnus and Vega in Lyra. On board, an extraordinarily sensitive camera would accurately record the brightness of the stars in the field. If Kepler saw the light of any one star temporarily dip, that could indicate the presence of an alien planet passing in front of, or ‘transiting’, that star. In particular, astronomers wanted to use the orbiting observatory to look for Earth-sized worlds orbiting within the habitable zones of their parent stars – the ‘habitable zone’ being the region around a star where water can exist as a liquid on a planet’s surface.

Initial success

ABOUT THE WRITER Will Gater is an astronomy writer and journalist. The author of several astronomy books, he also appears on TV and radio to talk about space. Find him on Twitter: @willgater

Kepler proved immensely successful at its job. To date it has discovered almost 1,000 confirmed exoplanets. One, a world catalogued as Kepler-186f, lies some 500 lightyears from our Solar System and is thought to be just 1.1 times the size of the Earth. Yet maintaining such an extraordinary vigil, watching just one small region of sky, required the spacecraft to be pointed very accurately. Kepler did this by using a device known as a reaction wheel. “Kepler was launched with four reaction wheels,” says the mission’s project scientist, Steve Howell. “These work in a similar manner to the gyroscopes we all played with as children. Three are required >

Kepler-186f is the most Earthlike planet the Kepler mission has discovered to date

skyatnightmagazine.com 2014

40

BALL AEROSPACE X 2, ESO/S. BRUNIER/NASA KEPLER MISSION, NASA/JPL/JHUAPL, THINKSTOCK X 7

the telescope to start observing again. The plan was adopted and now Kepler is experiencing a new dawn as it carries out what NASA calls the ‘K2’ mission. Rather than study a single field of stars, in K2 Kepler will observe multiple fields, spread across the sky, for roughly 80 days at a time. “K2 is a very different mission from Kepler,” says Thomas Barclay, who leads the Kepler Guest Observer Office, which is coordinating the K2 mission science. “It would be wrong to consider K2 as a somewhat less capable version of Kepler. Make no mistake, K2 can achieve scientific discoveries that Kepler was not capable of. Observing multiple fields allows us many chances to observe objects that were not observed in large numbers by Kepler.”

New targets for Kepler With the failure of two of Kepler’s four black reaction wheels, pictured here being fitted, its mission had to be redrawn

> to point a typical spacecraft, one for each of the three motions: roll, yaw, and pitch. By spinning the wheels faster or slower, the space telescope can be made to point with high precision in any given direction.” With each of the reaction wheels working smoothly, Kepler’s eyes remained resolutely fixed on its target. “It followed the single field of view to within a small fraction of one of its lightsensing pixels,” says Howell. But in July 2012 things started to go wrong. One of the reaction wheels stopped working. Then in May 2013, a second wheel failed. Without the three working reaction wheels needed to guide it, the future looked bleak for the exoplanet hunter. “We were all very sad to hear the news when the second wheel failed,” recalls Howell. “However, it was not a done deal in one moment: we had to look into the details, download more engineering data, try to assess the condition and failure.” In fact, it would only be a matter of months before a plan to save the spacecraft started to develop. With only two working reaction wheels, the radiation pressure from sunlight falling on the outside of the spacecraft would gradually nudge Kepler’s gaze away from what it should be looking at. Engineers realised, however, that by orientating Kepler in a certain way they could mitigate this effect and stabilise the spacecraft, thus allowing

Indeed, Kepler’s K2 observations should see it studying a diverse array of celestial targets, says Barclay, including supernovae and planets in our own Solar System as well as its traditional quarry, worlds around distant stars. “All science will be proposed by the community,” explains Barclay. “Every target observed by K2 will have been selected by a team of independent scientific reviewers who review over 100 proposals for each campaign.” One group vying for time on Kepler hopes to use the spacecraft to understand more about an important class of space rock – near-Earth asteroids, or NEAs. “They are flying mountains in space that come close to Earth’s orbit,” says Dr Martin Elvis of the Harvard-Smithsonian Center for Astrophysics, one of the researchers hoping to get time on Kepler. “That makes them scary – and tempting. Occasionally one will hit Earth, like the one that exploded over Chelyabinsk, Russia, in February 2013 and some of them contain material worth billions – if you can get it! They are also good intermediate steps for space explorers to learn to survive for a long time and at greater distances before we go all the way to Mars.” Despite astronomers knowing of over 11,000 near-Earth asteroids we still have much to learn about them. “We are actually falling behind rapidly in finding out anything detailed about them,” says Elvis. “Surveys find 1,000 of these asteroids a year but only about 10 per cent are followed up.”

KEPLER BY NUMBERS

4,234 978 10 The number of exoplanet candidates Kepler has identified since its mission began in March 2009. skyatnightmagazine.com 2014

The number of candidate worlds that have been verified as exoplanets.

The number of star fields across the sky that Kepler will look at in the K2 mission.

KEPLER’S K2 MISSION DECEMBER 41

1 6 5 2 0 9 7

4

8

3

This picture shows K2’s nine proposed target fields (1-9) and one calibration field (0) along Earth’s orbital plane

Demory of the University of Cambridge In particular, Elvis and his colleagues is leading a team that hopes to use want to use Kepler to examine the spacecraft to look for Earththe shape of some of them. sized exoplanets located within “Near-Earth asteroids are the habitable zones of a very not at all round, like the particular type of star. Death Star or our Moon, “The goal of Kepler’s but can be potato or primary mission was to even dog-bone shaped. determine the frequency How do we know? All of Earth-size planets asteroids spin and a orbiting in the habitable dog-bone shaped asteroid zone of Sun-like stars,” will seem brighter when it explains Demory. “The is long ways on to us than main difficulty is that the when it is end-on,” explains habitable zone of Sun-like Elvis. It’s here that Kepler’s stars is located far away from the sensitivity to small changes in star, because they are hot. It takes brightness can help. the Earth one year to complete a full “By following this brightening and Near-earth asteroids revolution, so to record three transits dimming as an asteroid spins we can come in a wide variety and confirm the nature of similar tell not only how fast it is rotating of shapes and sizes planets, we need three years.” – useful if you want to land on it – but The process of verifying that these worlds also how elongated it is,” says Elvis. “With really good measurements we can do a sort of ‘tomography’ actually exist can therefore take years. Combine this with the fact that these planets dim their parent and measure its shape in three dimensions. With stars by an extraordinarily small amount when they just a fraction of the K2 time allotted to near-Earth transit them and it soon becomes clear that finding asteroids, we could get brightness traces for almost an Earth-sized world orbiting in the habitable zone 200 a year to measure their shapes.” of a Sun-like star is no easy feat. “For these reasons and with the instruments available today, stars like our Sun are not the best basis for a search of small, Naturally, many of the proposals for K2 observing potentially habitable exoplanets,” argues Demory. > time involve studying exoplanets. Dr Brice-Olivier

The hunt for other worlds

2-4

The estimated remaining lifespan of the K2 mission in years, based on how much fuel Kepler has left.

1.1

At 1.1 times the size of Earth, Kepler186f is the nearest thing Kepler has found to a world like our own.

skyatnightmagazine.com 2014

42 KEPLER’S K2 MISSION DECEMBER

ESO, NASA/GSFC, THINKSTOCK X 7

The K2 mission will be used to hunt for planets orbiting M-type red dwarf stars

Due to launch in 2017, TESS is Kepler’s more powerful successor

skyatnightmagazine.com 2014

> Instead, it’s far smaller stars that he and his colleagues want to target with their K2 project. “An Earth-size planet transiting a dwarf star yields a light dip that is 100 times larger than for a star with the size of the Sun,” says Demory. “Small stars are also much cooler than the Sun, meaning that the habitable zone is significantly closer to the star.” Any planets orbiting in these habitable zones might therefore only take a few weeks to go around their diminutive parent star, giving the astronomers a chance to catch several transits in a relatively short space of time. “In this way we get a large signal-to-noise ratio much more rapidly than for larger stars,” explains Demory. And although these small stars, known as M-dwarfs, don’t shine brightly, they are abundant, accounting for about 70 per cent of the Milky Way’s stars. Demory and his colleagues don’t just want to uncover the worlds orbiting these stars, though. “Our second

goal is to initiate in-depth studies of these planets using the Spitzer and Hubble Space Telescopes,” he says. “These follow-up observations will allow us to determine whether these planets are rocky, if they have an atmosphere, whether they have strong climate patterns, and eventually whether biosignatures can be detected in their atmospheres.” Neither Kepler, Hubble nor Spitzer have the capability to sniff out the signs of life in the atmospheres of these alien worlds – that’s something that astronomers anticipate future missions like the advanced James Webb Space Telescope (JWST) will do. What Demory’s team are hoping, though, is that they might find a promising world that JWST can follow up. “We have not yet found one exoplanet similar to the Earth in terms of size and mass that would be a contender for biosignature detection with JWST,” he says. “We know, though, that these planets are common: we just have to find them before 2018, when JWST is slated for launch. Our K2 programme is one effort, among others, to discover at least one suitable planet in time for JWST to characterise it.”

The search continues Those other efforts include a mission that is something of an heir to Kepler – the Transiting Exoplanet Survey Satellite (TESS). TESS’s job, once it launches in 2017, will be to survey the whole of the night sky, studying over 200,000 stars in much the same way that Kepler did. The spacecraft’s ‘eyes’ will be four powerful CCD cameras with lenses that provide fields-of-view spanning some 24º. Like Kepler, TESS’s cameras will watch for the tiny dips in brightness that occur when an exoplanet passes in front of its sun. “TESS will focus on identifying planets between Earth and Neptune size that are in the habitable zone of their stars,” says project manager Jeff Volosin from NASA’s Goddard Space Flight Center. The stars TESS will be scrutinising are bright and nearby. That’s important, as it’ll make it easier for future telescopes like JWST to analyse the atmospheres of any worlds found orbiting these stars. “We hope to provide these future planet hunters with the best candidates possible for them to discover Earth-like planets,” says Volosin. The Kepler team reckons there’s enough remaining fuel on board the spacecraft to keep the K2 observations going for between two and four years. With TESS joining it in orbit in a few years, Kepler’s new mission undoubtedly signifies much more than just a new phase of life for the veteran space telescope: it could well be the beginning of a truly thrilling chapter in the search for a planet exactly like our own. S

44

DIRECT TO LOW-EARTH V BOEING

ORBIT

NASA has awarded contracts to take crew and cargo to the ISS from 2017. Paul F Cockburn reveals the winners and losers hen Space Shuttle Atlantis made its final landing at Kennedy Space Center on 21 July 2011, the Shuttle’s overarching mission programme was already 15 years beyond its intended end point, thanks in part to delayed completion of the International Space Station (ISS). But despite this, the agency did not have a successor ready to roll onto the launch pad, leaving almost every aspect of NASA’s space programme reliant on Russian rocketry. Recent hostilities have increased concerns that this relationship might not be as reliable as it once was. NASA is now readying alternatives, preparing for the first test flights of its new deep-space systems, the Orion Multi-Purpose Crew Vehicle and the Space Launch System, a Saturn V-sized rocket. Designed to carry crews to Moon, Orion has a December test launch, while the heavy launcher has a first flight slated for 2017. Meanwhile, in low-Earth orbit, servicing the needs of the ISS has been opened up to the commercial sector, with four companies bidding for the work. NASA selected two of these in September, in the hope that from 2017 US spacecraft will again fly to and from the ISS.

BOEING IMAGE, SPACEX, 1994-2014 SIERRA NEVADA CORPORATION, PHOTO PROVIDED BY BLUE ORIGIN

W

ABOUT THE WRITER Paul F Cockburn is a freelance journalist who has been writing about science and technology – past, present and future – since 1996. He is based in Edinburgh.

skyatnightmagazine.com 2014

Chicago-based Boeing is the largest beneficiary of the NASA contracts, having picked up around $4.2 billion worth of work, compared with the $2.6 billion allotted to smaller rival SpaceX. Despite the latter’s advantage in having already made commercial cargo deliveries to ISS, NASA reportedly has greater confidence in Boeing’s proven ability to deliver both technically and in terms of programme management. The Crew Space Transportation (CST)-100 has been designed to carry up to seven passengers or a mix of crew and cargo. Key features include reusability, a structure that requires no welding and the use of well-established Boeing technology, as well as onboard Wi-Fi. Boeing has already begun construction of three CST-100 vehicles at the Commercial Crew Processing Facility at Kennedy Space Center in Florida. Crewless test flights of the CST-100 are currently expected to commence by early 2017. www.boeing.com/cst100

SPACE TRAVEL DECEMBER 45

U SPACE X

Space Exploration Technologies Corporation – aka SpaceX, founded by former PayPal entrepreneur Elon Musk – had an ace up its sleeve when convincing NASA that its Dragon spaceship and two-stage Falcon rocket could successfully deliver both crew and cargo to the ISS. Because in May 2012, SpaceX was the first commercial company to actually deliver cargo to the station. SpaceX Dragon vehicles have since made four flights to and from the ISS. Each is capable of delivering

6,000kg of cargo, and returning half that mass to Earth. The company modestly describes Dragon as being “the only spacecraft currently flying that is capable of returning significant amounts of cargo to Earth”. As a precursor to crewed flights, part of any cargo is held within a pressurised section – referred to as ‘the capsule’ – which ensures that SpaceX now only awaits official certification before manned tests can begin. www.spacex.com/dragon

U SIERRA NEVADA CORPORATION Sierra Nevada Corporation’s (SNC) Dream Chaser is a reusable spacecraft that they believe provides “a flexible and affordable space transportation solution for low-Earth orbit destinations” and other space missions. While launched into space using the proven means of an Atlas V rocket, Dream Chaser is designed to glide back to Earth in much the same way as the Space Shuttle – providing a low-G re-entry that protects crew, cargo and scientific samples. Unlike the Shuttle, however, the vehicle’s non-toxic, on-orbit propulsion system (derived from SNC’s SpaceShipTwo hybrid rocket motor) and ethanol-based reaction control system thrusters mean it is not only environmentally safer but could also potentially land on any suitable commercial runway. Despite NASA’s decision, which SNC is disputing, it continues to develop Dream Chaser for other commercial opportunities. www.sncspace.com/ss_space_ exploration

U BLUE ORIGIN

Set up by Amazon founder Jeff Bezos, private aerospace company Blue Origin aims to “lower the cost of spaceflight so that many people can afford to go, and so that we humans can better continue exploring the Solar System”. It has worked with NASA for many years, not least within the agency’s Commercial Crew Development (CCDev) programme to support future human spaceflight to the ISS. The USP of Blue Origin’s vehicle design is its biconic hull, made from two cones. This

provides a better lift to drag ratio for atmospheric flight than a simple cone shape, and also makes it easier for the parachute system to slow its descent back to Earth. On 17 September, the day following NASA’s selection process, Blue Origin announced a partnership with major US launch system operator United Launch Alliance to develop a new affordable, reliable and US-designed rocket engine. www.blueorigin.com

skyatnightmagazine.com 2014

THE SKY GUIDE DECEMBER 47

PLUS Stephen Tonk in’s

BINOCULA

R T OU R

Turn to pag e 58 for six of this mon th’s best binocular si ghts

The Sky

Guide

December The annual Geminid meteor shower reaches its peak on the morning of 14 December. Despite the presence of a last quarter Moon in the sky this year, plenty of meteors should still be visible.

PETE LAWRENCE

Written by Pete Lawrence Pete Lawrence is an expert astronomer and astrophotographer with a particular interest in digital imaging. As well as writing The Sky Guide, he appears on The Sky at Night each month on BBC Four.

skyatnightmagazine.com 2014

48

Highlights Your guide to the night sky this month This icon indicates a good photo opportunity

1

MONDAY The amazingly dynamic planet Jupiter now comfortably reaches its highest point in the sky in complete darkness. Look due south around 05:00 UT to see the planet high in the sky. At mag. –2.1 it’s difficult to miss!

2

TUESDAY The waxing gibbous Moon (77% lit) makes a close pass of Uranus around 00:00 UT. The Moon starts getting close to the planet from 22:00 UT on 1 December; at 00:30 UT on the 2nd, its southern limb is just 20 arcminutes away from the planet.

7

SUNDAY X Lunar libration favours the northern region of the Moon from today until 12 December. This means that libration zone craters such as Hermite, Byrd, Peary and Florey may be seen. See page 51.

12

FRIDAY The waning gibbous Moon (71% lit), mag. –2.2 Jupiter and mag. +1.4 Regulus (Alpha (_) Leonis) form an ‘almost’ equilateral triangle at 04:30 UT, visible due south.

20

SATURDAY The waning crescent Moon is just 3% lit. Catch it 6° to the east of mag. +0.9 Saturn at 06:45 UT, lying low in the southeast. Jupiter’s moon Europa occults Io between 05:31 UT and 05:51 UT. See page 51.

PETE LAWRENCE X 7

25

THURSDAY The often overlooked open cluster M35 is riding high after 22:00 UT. Find it by extending a line from mag. +2.1 Saiph (Kappa (g) Orionis) through mag. +0.5 Betelgeuse (Alpha (_) Orionis) and continuing for the same distance again. Binoculars show it well.

skyatnightmagazine.com 2014

13

SATURDAY Jovian moon Europa will occult its inner neighbour Io this morning. Use a telescope to catch the event unfolding between 01:15 UT and 02:24 UT. See page 51.

21

SUNDAY A waning crescent Moon, less than 1% lit, can be seen rising an hour before the Sun. At 07:30 UT it’ll be 2° up in the southeast, and 13° left mag. +1.1 Antares (Alpha (_) Scorpii) from the centre of the UK. Jupiter’s moon Callisto eclipses Io from 03:13 UT to 03:31 UT. Ganymede occults Io between 04:11 UT and 04:22 UT.

14

SUNDAY The Geminid meteor shower reaches peak activity at 12:00 UT. See page 50.

Jupiter’s moon Ganymede partially occults Io from 01:06 UT to 01:15 UT, and totally occults Io from 21:00 UT to 21:55 UT.

22

MONDAY The evening twilight contains a very thin waxing crescent Moon. With clear skies, it may be visible 8.5° to the right of mag. –3.8 Venus. The annual Ursid meteor shower reaches its peak tonight, with a rate of 10 meteors per hour.

28

SUNDAY Although still rather low, mag. +8.5 comet C/2014 Q2 Lovejoy is climbing higher in the sky. At 23:00 UT it can be found less than 1º southeast of globular cluster M79 in Lepus. The comet closes in on the cluster for the remaining part of the night.

THE SKY GUIDE DECEMBER 49

What the team will be observing in December Pete Lawrence “I’m looking forward to imaging some of the amazing mutual events involving the four Galilean moons of Jupiter. Tiny though the moon discs are, the challenge of getting some detail is rather exciting.”

6

SATURDAY X A bit of Jovian magic occurs this evening as the giant moon Ganymede occults Io. The event starts at 22:11 UT and ends seven minutes later at 22:18 UT. Jupiter is low in the east during the event. See page 51.

Steve Marsh “With the lunar north pole well presented this month I’m going to try to resolve the rille running through the middle of the Vallis Alpes. It’s less than 1km wide in places so should push my equipment to the limit.”

9

TUESDAY The waning gibbous Moon (92% lit) will occult mag. +3.6 Lambda (h) Geminorum at around 06:00 UT. Actual times vary with location, so view from around 05:30 UT to make sure you don’t miss it. Reappearance is about one hour later, again dependent on location.

Stephen Tonkin “I’ll be hoping for clear skies between dusk and midnight moonrise from the 13th to 15th. This is the broad peak of the very reliable Geminid meteor shower.”

Need to know

The terms and symbols used in The Sky Guide

19

FRIDAY X It’s the time of year when magnificent Orion dominates the sky. At midnight, this most iconic of constellations lies due south. The beautiful Orion Nebula, M42, is a highlight of the region located right in the middle of the Hunter’s sword.

UNIVERSAL TIME (UT) AND BRITISH SUMMER TIME (BST) Universal Time (UT) is the standard time used by astronomers around the world. British Summer Time (BST) is one hour ahead of UT.

RA (RIGHT ASCENSION) AND DEC. (DECLINATION) These coordinates are the night sky’s equivalent of longitude and latitude, describing where an object lies on the celestial ‘globe’.

HOW TO TELL WHAT EQUIPMENT YOU’LL NEED NAKED EYE

23

TUESDAY As twilight falls, look for the always beautiful sight of a waxing crescent Moon (3% lit) and mag. –3.8 Venus low in the southwest after sunset.

Allow 20 minutes for your eyes to become dark-adapted

BINOCULARS 10x50 recommended

PHOTO OPPORTUNITY Use a CCD, planetary camera or standard DSLR

SMALL/MEDIUM SCOPE Reflector/SCT under 6 inches, refractor under 4 inches

LARGE SCOPE

29

MONDAY The shadow of Ganymede eclipses Callisto between 05:52 UT and 06:04 UT this morning. See page 51.

30

TUESDAY Europa will occult Io from 21:38 UT until 21:49 UT this evening. See page 51.

Reflector/SCT over 6 inches, refractor over 4 inches

Getting started in astronomy If you’re new to astronomy, you’ll find two essential reads on our website. Visit http:// bit.ly/10_Lessons for our 10-step guide to getting started and http://bit.ly/First_Tel for advice on choosing your first scope.

skyatnightmagazine.com 2014

50

DON’T MISS…

3 top sights

The Geminid meteor shower WHEN: 4-17 December, peak nights 13/14 and 14/15 December

Geminids radiant 10 Dec

14 Dec 12:00 UT (peak)

GEMINI ¡

15 Dec

_

20 Dec

M35

5 Dec

Pollux

Castor

a

` b

Moon rises at 23:30 UT on 13 December

Moon rises at 00:30 UT on 15 December

54%

44%

The bright Moon will make for challenging observing conditions, but you’ll still be able to see bright trails

PETE LAWRENCE X4

THE GEMINID METEOR shower arguably puts on the best display of the year, although fans of the Perseids, which peak on 13 August, may disagree. The reason why this split occurs is that the Perseids peak when the nights are shorter and warmer. Mid-December has around 12 hours of true darkness compared to just 3.5 hours in mid-August, so the Geminids are a test of stamina! There will be some Moon interference this year. The

!

NEED TO KNOW

An object’s brightness is given by its magnitude. The lower the number, the brighter the object: with the naked eye you can see down to mag. +6.0.

skyatnightmagazine.com 2014

last quarter Moon rises around 23:30 UT on 13 December, remaining above the horizon for the rest of the night. On the following night the marginally thinner Moon rises an hour later, at 00:30 UT on the 15th. Peak activity for this year’s display is expected at 12:00 UT on 14 December, which is of course in broad daylight. After midnight, Earth turns so that the meteoroids that create the shower hit our atmosphere head-on, leading to heightened rates. Consequently the best activity is likely to be seen on the morning of 14 December,

which is the closest morning to the peak. The Geminid shower has a zenithal hourly rate (ZHR)

The night of 13/14 December offers your best chance of seeing the Geminids in action

of 120 meteors per hour compared to the Perseids’ lower figure of 100 per hour. Now this may sound like you’re going to see two meteors every minute, but that’s not how the ZHR figure works. The ZHR of a meteor shower is a way to normalise activity so that rates can be compared between different showers. It’s a figure that assumes a perfect sky and the radiant – the area the shower meteors appear to emanate from – being overhead at the zenith. It also assumes you can observe the entire sky in one go, which isn’t actually possible. The biggest factor affecting the number of meteors seen is the Moon’s glare. This is likely to reduce the visual rate to around 15-20 per hour. A bright Geminid passing across the heavens is a wonderful sight and even with the Moon’s disruptive influence, an all-night watch on 13/14 December is highly recommended if the weather stays clear. A meteor may appear anywhere, but if you need a direction to view, look up at a height of about 60°, or two-thirds of the way up the sky. Look at this height in any direction that the Moon isn’t spoiling the view. Try to keep your eyes dark adapted and avoid looking at the Moon. And if you fancy having a go at photographing the shower, turn to page 60 for advice on how to create a Geminid activity composite.

THE SKY GUIDE DECEMBER 51

Lunar libration favours the north polar region WHEN: 6-12 December Rozhdestvenskiy Hermite Florey

Peary Byrd

Mouchez

Scoresby Philolaus Goldschmidt

Barrow

Epigenes Timaeus Mare Frigoris

Plato

The Moon’s libration brings some features that are normally hidden into view in early December

THE MOON PRESENTS the same face towards Earth throughout the course of the lunar month, by virtue of the fact that it rotates once on its axis for every revolution around our planet. However, the fact that the Moon’s orbit is elliptical means that its orbital speed varies, being

faster when it’s closer to Earth. This variation in speed allows us to see around the eastern and western limb of the Moon. Similarly, the Moon’s orbit is tilted slightly to the plane of the ecliptic and this means that we also get to see a little more of the surface over the northern and

southern limb from time to time. The combined rocking and rolling effect is known as lunar libration and over time it allows us to see an extra nine per cent of the Moon’s surface than would be possible if the Moon’s face were strictly fixed relative to the Earth. The remaining 41 per cent remains only visible from spacecraft! Catching features with favourable libration can be tricky and patience is required. This is because the phase also needs to work with the libration to show features off to best effect. It’s no good having a favourable libration for the western limb, for instance, only to have that part of the Moon in permanent shadow due to lunar night. This month, the libration is favourable for the northern limb between the dates of 6-12 December. At this time, craters such as Byrd, Peary and Florey will become visible, along with Hermite, which is famous because its permanent shadows contain regions where the lowest recorded temperature in the Solar System has been measured. On 10 December, it may also be possible to catch sight of the 177km crater Rozhdestvenskiy, right on the northern edge of the Moon.

Galilean moon mutual events WHEN: 6, 12, 13, 14, 21, 24 and 30 December

THERE ARE SOME great mutual satellite events between Jupiter’s moons this month. On 6 December between 22:11 UT and 22:19 UT, Ganymede almost totally occults Io. On 12 December, it’s Europa’s turn to pass across Io. Although this isn’t such a complete occultation, both objects will have a similar apparent size. This event occurs between 23:09 UT and 00:21 UT on the 13th. A repeat meeting on 13 December almost results in a complete transit of Europa across Io’s disc. This occurs between 01:15 UT and 02:24 UT. Ganymede finally manages to totally occult Io on 14 December between 21:00 UT

and 21:55 UT. Callisto’s shadow passes across the disc of Io on 21 December: the whole event starts at 03:13 UT and concludes at 03:32 UT, mid-eclipse being at 03:22 UT. Europa’s shadow eclipses Ganymede on 24 December with mid-eclipse at 06:34 UT,

the entire event lasting from 06:24 UT to 06:45 UT. Finally, there’s a decent partial occultation of Io by Europa on 30 December between 21:38 UT and 21:49 UT. It’s great fun observing these events, especially as they happen pretty quickly. Small

!

NEED TO KNOW

The zenithal hourly rate of a meteor shower is the expected number of meteors seen under perfect conditions with the radiant point of the shower overhead.

telescopes will show the moon dots closing in on one another during an occultation, while an eclipse may result in the eclipsed moon dimming. Large telescopes under steady skies may actually be able to show the discs interacting.

E 2” N

20:48:49 20:56:37 21:04:24 21:12:12 21:20:00 21:27:48 21:35:36 21:43:24 21:51:12 Simulated view of the total occultation of Io by Ganymede on 14 December (all times are UT)

skyatnightmagazine.com 2014

52

Mercury, Venus and the Moon will line up just after sunset on 23 December

Mercury and Venus will be just 3° apart shortly after sunset on New Year’s Eve

The planets Moon

PICK OF THE MONTH VENUS BEST TIME IN DECEMBER: 31 December, 16:30 UT ALTITUDE: 5º (low) LOCATION: Sagittarius DIRECTION: Southwest RECOMMENDED EQUIPMENT: Naked eye or binoculars FEATURES OF INTEREST: Phase, subtle shadings on planet’s disc

PETE LAWRENCE X 3

Venus

Venus

VENUS IS MAKING a welcome return to the evening sky and this month can be seen low in the southwest after sunset. This is an impressively bright planet, shining away at mag. –3.8. This helps make it visible despite the bright twilight it’s located in just after sunset. Visibility improves throughout the month, but the planet remains low in the southwest after the Sun has gone down. The end of the year marks a turning point for the visibility of Venus, as the planet slowly starts to pull away from the Sun and the steepness of the ecliptic increases relative to the horizon. This means that the period of time for which the planet remains above the horizon after sunset increases, turning Venus into something of a beacon in the next few months. Telescopically, there’s not much to see at present. The planet is on the far

Mercury

Mercury SW

SW

Venus is at the centre of some striking alignments towards the end of the month

side of its orbit relative to Earth so it looks fairly small and fully illuminated. On 31 December, Venus will be 96% lit and have a 10-arcsecond disc. There’s a lovely encounter with the waxing crescent Moon on 23 December. On this date, the 3%-lit lunar crescent will be just 9° above Venus after the Sun has gone down. On New Year’s Eve, mag. –0.7 Mercury will be just 3° from Venus. The two

planets are heading for a really close encounter on 11 January 2015, when they’ll appear just 40 arcminutes apart. If you have clear skies from the end of the year, why not try and take photos of the pair at the same time each evening, to show how they gradually move together? It’s been a while since Venus has given us a good show in the evening sky, but now it’s back, its sure to become the ‘star’ of the show over the next few months.

As December rolls on, bright Venus will be visible in the evening twilight for longer

THE PLANETS IN DECEMBER The phase and relative sizes of the planets this month. Each planet is shown with south at the top, to show its orientation through a telescope VENUS 15 December

MARS 15 December

JUPITER 15 December

SATURN 15 December

URANUS NEPTUNE 15 December 15 December

MERCURY 1 December

MERCURY 15 December

MERCURY 31 December 0”

skyatnightmagazine.com 2014

10”

20” 30” 40” ARCSECONDS

50”

60”

JUPITER BEST TIME IN DECEMBER:

31 December, 03:00 UT ALTITUDE: 52º LOCATION: Leo DIRECTION: South Jupiter continues to improve: it culminates (reaches its highest point in the sky) just after 05:00 UT on 1 December, but by month end it’s in this position at 03:00 UT. In the same period it brightens from mag. –2.1 to mag. –2.3 and its disc grows from 39 arcseconds to 43 arcseconds. On 1 December, Jupiter is located 7.5° from mag. +1.4 Regulus (Alpha (_) Leonis) in Leo. On the 12th, a waning gibbous Moon (71% lit) joins the scene 6° south of the planet, forming an attractive triangle. URANUS BEST TIME IN DECEMBER:

1 December, 20:15 UT ALTITUDE: 41º LOCATION: Pisces DIRECTION: South Uranus remains well placed, culminating as darkness falls on New Year’s Eve. It is currently at mag. +5.8, and with clear skies should be visible to the naked eye a little under 3.5° south of mag. +4.4 Delta (b) Piscium. A waxing gibbous Moon (77% lit) passes within just 36 arcminutes of the planet at 00:20 UT on 2 December.

little less than 1º west of mag. +4.8 Iota (f) Aquarii. SATURN

December

31 December, 05:30 UT ALTITUDE: 13º LOCATION: Scorpius DIRECTION: South-southeast

Saturn is a morning object best viewed at the end of the month. Its mag. +0.8 dot can be seen above and to the right of mag. +1.1 summer star Antares, the alpha star of the constellation of Scorpius, the Scorpion. A waning crescent Moon (3% lit) can be seen to the lower left of the planet on the morning of the 19th.

Using a small scope you’ll be able to spot Jupiter’s biggest moons. Their positions change dramatically during the month, as shown on the diagram. The line by each date on the left represents midnight. DATE

WEST

EAST

1 2 3 4 5 6

MERCURY BEST TIME IN DECEMBER:

31 December, 16:15 UT ALTITUDE: 3º (low) LOCATION: Sagittarius DIRECTION: Southwest Mercury starts the month as a morning object but is too close to the Sun to be seen comfortably. Superior conjunction occurs on 8 December; the planet’s subsequent visibility in the evening is a bit limited, but there’s a great chance to spot mag. –0.8 Mercury, mag. –3.8 Venus and a waxing crescent Moon (1% lit) in the evening sky on 22 December, though all three objects will be very low following sunset. MARS

NEPTUNE

BEST TIME IN DECEMBER:

BEST TIME IN DECEMBER:

25 December, 18:00 UT ALTITUDE: 11º LOCATION: Capricornus DIRECTION: Southwest Mars is a first-magnitude evening object in Capricornus, visible low in the southwest as darkness falls. Through a telescope, Mars is quite small at present, appearing just 4 arcseconds across. A waxing crescent Moon (12% lit) sits close by on the 25th.

1 December, 18:00 UT ALTITUDE: 27º LOCATION: Aquarius DIRECTION: South Neptune lies due south as the sky gets dark at the start of December, but drifts lower by the end of the month. Consequently, the best views are to be had early on in the month. Mag. +7.9 Neptune is currently in Aquarius, just a

JUPITER’S MO ONS

BEST TIME IN DECEMBER:

See what the planets look like through your telescope with the field of view calculator on our website at: http://www.skyatnightmagazine.com/astronomy-tools

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 8

7 6

5 4

3

2 1

0

1 2

3 4

5 6

7 8

arcminutes

Jupiter

Io

Europa

Ganymede

Callisto

54

The Northern Hemisphere RT O N

HOW TO USE THIS CHART

GLOBULAR CLUSTER

1. HOLD THE CHART so the direction you’re facing is at the bottom. 2. THE LOWER HALF of the chart shows the sky ahead of you. 3. THE CENTRE OF THE CHART is the point directly over your head.

`

DIFFUSE NEBULOSITY

k

PLANETARY NEBULA

`

OPEN CLUSTER

a er

GALAXY

On other dates, stars will be in slightly different places due to Earth’s orbital motion. Stars that cross the sky will set in the west four minutes earlier each night.

a

CONSTELLATION NAME

R

PERSEUS

STAR NAME

AJO

Arcturus

1 DECEMBER AT 00:00 UT 15 DECEMBER AT 23:00 UT 31 DECEMBER AT 22:00 UT

H E AS T

STAR CHARTS

WHEN TO USE THIS CHART

1 M5

KEY TO

LEO

DOUBLE STAR

R

NO

a

LEO

THE MOON, SHOWING PHASE

MI

VARIABLE STAR

_

Sickle

¡

COMET TRACK

L Regu

a

THE SUN IN DECEMBER*

M4

X

et rcl Ci

SUNSET

1 Dec 2014

08:02 UT

15:55 UT

11 Dec 2014

08:15 UT

15:50 UT

21 Dec 2014

08:23 UT

15:52 UT

31 Dec 2014

08:26 UT

16:00 UT

S

10

th

Pro

5 Dec 2014, 15:41 UT

21 Dec 2014, 07:14 UT

9 Dec 2014, 19:13 UT

25 Dec 2014, 10:18 UT

13 Dec 2014, 23:27 UT

29 Dec 2014, 12:07 UT

MONDAY

TUESDAY 2

WEDNESDAY THURSDAY 3

4

FRIDAY 5

SATURDAY 6

SUNDAY 7

MAG. +3

N

E

8

15

9

16

10

17

11

18

12

19

13

20

14

21

S MILKY WAY

22

23

24

30

31

NEW MOON

29

skyatnightmagazine.com 2014

25

26

27

28

M5

0

Ros

ette

OS

M4

7

a

S EA

W COMPASS AND FIELD OF VIEW

_

b MO NO CER

M4 6

FULL MOON

H UT SO

5º

INOR

*Times correct for the centre of the UK

1

MAG. +4 & FAINTER

CANIS M

De tou ep-s r, p ky 57

17 Dec 2014, 02:43 UT

`

MAG. 0 & BRIGHTER

1 Dec 2014, 13:34 UT

n cyo _

MOONRISE TIMES

STAR BRIGHTNESS:

MAG. +2

A

THE MOON IN DECEMBER*

QUASAR

MAG. +1

`

DR

PLANET

4

HY

SUNRISE

b

ASTERISM

DATE

b

METEOR RADIANT

x Pollu `

CA N

CE

R

Jupiter

lus

STAR-HOPPING PATH

_

EAST

ASTEROID TRACK

T

Sirius

b

M

NORTH

a

M2

US G

N

_

b

PH EU

S

M39

T

Pea

`

Ald

CE

` a

House

_

b

e

_ U

LACERTA

bh Du

at he Sc

`

R

_

S

`

M33

Algol

M36

_

R

a

GU LUM

a

US

Ecliptic

7th

Hyad

_

ra

_

n r nka _ Me

`

_

b a

CE

`

TUS

`

` Rige l

_

k

ES T

M Ve irror nu of s

f M4 2

Mira

b

ERIDANUS

b

O

m e

a

tor

Celestial Equa

ORION

a

UT HW

le ng W

c

b

SC

31st

4th

a ¡

b

ba

trix

lla Be

M78

1st

de

_

th 28

Al

use

lge

te Be

b V a

es

a

b

TAU R

`

PI

es Ple iad

Elnath

c

a

_

S ARIE

ES

Ha

m

NI

al

7

MI

M3

GE

M38

b a

S SEU PER

`TRIAN

let

¡

_

`

b

Circ

_

`

M34

Kids

A

`

WEST

k

MED

a

_

SU

M32

DRO

GA

81

pha Mir

AN

PE

M31

Alpheratz

10

Gr e of at S Pe qu ga ar su e s

R

M1

_

M

`

b

Castor

AU RIG A

CY

URSA MINOR

in

era m

` k 2 Ursid 2D s ec

_

Deneb

CA

Do Clu uble ste r

Capella

M1

Tri a

9

Su

Alcor

_ Kocha b

A

PEI

O SSI

a

` M35

er

e mm b

AF

b

a

_

M

b

s Geminid Dec Peak 13

int

N

ng

ria rT

an ub Th

CO

DR A

Pol aris

M82 RR

ebu la

O

Cr

No rth

_

r

_ Scheda W

3

10

S

CANIS MAJOR

ern

01

gh

`

a b

LYNX

RT HW

M1

Plou

M52

PA R

LIS

M41

os s

b M EL

DA

`

ES T

Mizar

S

UR

CA

O

eN

RR

le

Ly r

a

THE SKY GUIDE DECEMBER 55

S

rak a

u

Za

LEPUS `

M79

SOUTH

skyatnightmagazine.com 2014

56

Deep-sky tour Our December star trek takes us to the faint constellation of Monoceros, the Unicorn  �

Tick the box when you’ve seen each one



3

4

1

2

BETA MONOCEROTIS

This month’s targets are all in the constellation of Monoceros, the Unicorn. Begin at Orion’s Belt and imagine a line to mag. –1.5 Sirius (Alpha (_) Canis Majoris). Just above the mid point of this line are two fourth-magnitude stars; the one slightly closer to Sirius is our first target, mag. +4.6 Beta (`) Monocerotis. In a small scope at 100x, this star is revealed to be a lovely double, with components of equal brightness lying 7.4 arcseconds apart. Increasing magnification reveals that the southern star is itself a double. Its components are also of equal brightness, but much closer – just 2.8 arcseconds apart. This glorious triple system is one of the best in the sky. The closer pair orbit one another every 4,200 years, while the more distant star takes 14,000 years to orbit the these two. � SEEN IT

NGC 2232

Open cluster NGC 2232 sits 2.3° to the north of Beta Monocerotis. It’s relatively easy to locate, thanks to the presence of fifth-magnitude star 10 Monocerotis within the cluster. The 20 or so members that form NGC 2232 are fairly easy to see, even with a small telescope, but the richness of the surrounding area and the loose nature of the cluster can make positive identification less straightforward. This is not really helped by the fact that there’s no real condensation at the heart of the cluster to guide your eye. This object, which lies 1,305 lightyears from Earth, is best seen using a low magnification of 50x or less. � SEEN IT

skyatnightmagazine.com 2014

5

6

NGC 2244

There’s no problem identifying our next target, open cluster NGC 2244 – which lies at the heart of the Rosette Nebula. For many stargazers, this is the first part seen when looking for the nebula, and the low surface brightness of the Rosette often means it can also be the only part seen! The most striking thing about the cluster’s appearance is its two parallel lines of three stars of similar brightness. A small scope easily shows these stars along with about 15 or more others. The middle stars of each line are easy-to-split doubles. This is a young cluster, formed out of the Rosette Nebula’s gas less than five million years ago. � SEEN IT

THE ROSETTE NEBULA

Once you’ve found NGC 2244, you’ve found the Rosette Nebula. This is a large object with low surface brightness, which makes it tricky to see. It spans an area equivalent to five full Moons and has several separate catalogue entries: NGC 2237, 2238, 2239 and 2246. It’s visible in a small telescope, but you’ll need good skies and a low-magnification eyepiece. An ultra-high contrast or OIII filter is highly recommended. If you’re struggling, remember that the nebula is roughly circular, centred on NGC 2244 and has a diameter equal to 4x the length of the main six-star pattern in the cluster. � SEEN IT

THE CHRISTMAS TREE CLUSTER

Our next target is the Christmas Tree Cluster, which gets its name from the fact that it looks like the outline of a classic Christmas tree. Locate fourth-magnitude 8 Monocerotis, 2° east of NGC 2244, and fourth-magnitude 13 Monocerotis a similar distance north of the cluster. A line from the first through the other and extended for the same distance again will bring you to S Monocerotis. This variable star (mag. +4.62 to +4.68) marks the tree trunk and is an easy find through a finderscope. The tree outline heads south from the trunk, formed mostly of eighth- and ninth-magnitude stars. Mag. +7.2 HD 47887 marks the tip, 25 arcminutes south of S Monocerotis. � SEEN IT

THE CONE NEBULA

Our last target, the Cone Nebula, shares the same NGC 2264 designation as the Christmas Tree Cluster. This is an object that requires patience and dark skies to see. Start at S Monocerotis, looking for the faint nebula that surrounds it and the small group of stars off to the southwest. If a glow is visible, the omens are good for the Cone Nebula. Look for an area of nebulosity south of HD 47887, the star at the apex of the Christmas Tree shape. The Cone appears as a dark triangle within glowing nebulosity, arranged so that it’s like a reflection of the tree. It’s caused by dark intervening material in front of a brighter nebula. � SEEN IT

CHART: PETE LAWRENCE; PHOTO: THINKSTOCK

The Christmas Tree Cluster sits at the centre of this image, with the Cone Nebula below it

07h

Alzirr

j

GEMINI

S Mon

Christmas Tree Cluster

5

_

NGC 2264

HD 47887

+10º

+10º

06h

6

Betelgeuse

NGC 2251

Cone Nebula

ORION

13 NGC 2236

Collinder 111

Collinder 97

3NGC 2244

Collinder 106 Collinder 107

8

4

Rosette Nebula

MONOCEROS

Collinder 91

Collinder 96

00

18

06h

NGC 2301

00

b

2 NGC 2232

N

a

5º

W

2.5º

`

E

-10º

M50

S

NGC 2335

-10º NGC 2353

NGC 2343

07h

1

e

CANIS MAJOR

Menkar

_

5º

a

E

4

Double Cluster

`

Stock 2

S

3

Algol

N

PERSEUS

W

1

NGC 663 M103

M34

2

Ruchbah

b

CASSIOPEIA

NGC 457

a a

TRIANGULUM a

ARIES

`

Almaak

NGC 281

Schedar

_

NGC 752

`

5

_

Hamal

Metallah

_

M33

6

`

ANDROMEDA Mirach

` M31

LACERTA

a

_

PISCES

b

Binocular tour This month’s destinations include the head of a demon and a bodybuilding stick man

With Tick the box when you’ve seen each one Stephen Tonkin �

1 ALGOL

CHARTS AND PICTURES: PETE LAWRENCE

10 x Algol (Beta (`) Persei) is an eclipsing 50 binary star. It dips in brightness from mag. +2.1 to +3.4 for about 10 hours every 2.85 days, when the fainter star passes in front of the brighter one. In Greek legend, this star represents the petrifying eye of Medusa. Its name comes from ‘Ras al Ghul,’ which means ‘the head of the demon’. It’s an ideal first star for anyone who wants to start observing variable stars, and now is a good time to spot it – Algol will be high in the evening sky for several months. � SEEN IT

2 M34

10 x Open cluster M34 can be seen with the 50 naked eye and averted vision on a transparent night, but in binoculars it is superb. Find it 5° from Algol in the direction of mag. +2.3 star Almaak (Gamma (a) Andromedae). To the naked eye M34 takes the guise of a fuzzy patch with a similar apparent size to the Moon; a pair of 10x50s can, depending on sky conditions,

skyatnightmagazine.com 2014

show a dozen or so stars, the brightest of which form a bent H shape. � SEEN IT

3 THE DOUBLE CLUSTER

15 x Imagine a line from mag. +2.2 Gamma (a) 70 Cassiopeiae to mag. +2.7 Ruchbah (Delta (b) Cassiopeiae) and extend it a further 7.5° to the southeast. Here you will find a close pair of open clusters, NGC 869 and NGC 884 – better known as the Double Cluster. Again, they’re visible to the naked eye, but you really need big binoculars to bring out the variations in colour and brightness that give the group a 3D appearance. To give you an idea of the brightness of these stars, if our Sun was there, you’d be unable to see it with 15x70s. � SEEN IT

4 THE MUSCLEMAN CLUSTER

10 x Slightly more than 2° north of the Double 50 Cluster is another large, sparse cluster of stars. The brighter ones have the form of a stick man in bodybuilder pose. This is Stock 2, nicknamed the Muscleman Cluster. It appears

to be pulling a chain of stars away from the Double Cluster. This is purely a line-of-sight illusion, because the Muscleman is only 1,050 lightyears away, compared to the 7,200- and 7,500-lightyear distances of the two components of its ‘neighbour’. � SEEN IT

5 NGC 752

15 x Find the mag +3.0 Beta (`) Trianguli and 70 place it at the left of the field of view. Mag. +5.7 open cluster NGC 752 (also designated Caldwell 28), should be near the right-hand side, above a close pair of deep yellow 6th-magnitude stars. This is another object that benefits from a larger aperture, and with a pair of 15x70s you should be able to resolve at least three stars against a background glow that is nearly twice the apparent size of the Moon. Like the Muscleman Cluster, NGC 752 is relatively close at a distance of 1,200 lightyears. � SEEN IT

6 THE TRIANGULUM GALAXY

10 x We’ve left the Triangulum Galaxy, M33, 50 until last because you will need darkadapted eyes as well as a transparent sky to find it. Locate mag. +2.1 Mirach (Beta (`) Andromedae) and scan the region that is two-thirds of the way to mag. +3.4 Metallah (Alpha (_) Trianguli). Here you will find the large faint circular ghostly glow of M33. It is face-on to us and spread out over an area of sky that is even larger than NGC 752, making it very faint. Its size makes it one of several objects that is easier to see in a pair of 10x50s than in a small telescope. � SEEN IT

THE SKY GUIDE DECEMBER 59

STATISTICS

Moonwatch Crater Alexander MOST LUNAR CRATERS are fairly well defined, appearing either as circles when seen face on or, as is more often the case, as ellipses when seen foreshortened close to the lunar limb. Alexander is an 83km rectangular-shaped crater which is very old and eroded. Look for it through a telescope and its vague outline is easily missed. The crater actually resembles a small patch of lava nestled in the northeast corner of the Caucasus mountain range. The best way to locate it is to first identify the distinctive 88km-wide crater Aristoteles. From here, look 195km south of the centre of Aristoteles to locate the centre of crater Eudoxus (68km). The centre of Alexander lies 135km south and slightly west of the centre of Eudoxus. Its flat lava floor is the best give-away, as the rim bordering the western half is easily mistaken for part of the Caucasus range. The smooth floor gradually gives way to rougher terrain to the east that looks like it has been splattered by material, probably from the formation of one of the larger craters nearby. As ever, things start to get interesting when the Sun’s altitude in the lunar sky drops. This occurs when the terminator, the line that defines the division between lunar night and day, is nearby. The most interesting illumination occurs during the Moon’s waxing phase, when the floor of Alexander is still just in darkness. At such times, the eroded rim to the west and southwest can catch the Sun’s rays to form a delicate ‘necklace’ of sparkling peaks. At such times, the outline of the crater is actually much

easier to visualise. With oblique illumination the otherwise smooth-looking floor of Alexander takes on a different persona. There are plenty of small features on view including rilles (cracks), tiny craterlets and gentle hills. Hop over the southwest rim and the next prominent feature is the 33km-diameter crater Calippus. Actually, the term ‘diameter’ is misleading here as the feature is quite misshapen and almost beanlike in shape. The lofty peaks of the Caucasus mountains tower to the west and one of

N

TYPE: Eroded crater SIZE: 83km AGE: 3.9-4.6 billion years LOCATION: Latitude 40.3°N, longitude 13.7°E BEST TIME TO OBSERVE: Six days after new Moon or five days after full Moon (12-13 December and 28-29 December) MINIMUM EQUIPMENT: 2-inch telescope

these casts a beautiful sharp point when the sunlight angle is low as shown in our photo. The ever roughening terrain as you travel east along the floor of Alexander merges with the equally rough terrain that borders the northern edge of Mare Serenitatis. It’s hard trying to see much order in

E

this uneven lunar landscape, but some is there to be had in the form of satellite craters to Alexander and Eudoxus to the north. In the thin strip to the south of Alexander lies 5km Alexander C. Go north from here inside Alexander and you’ll find the 4km craterlets Alexander B and Alexander A.

“The most interesting illumination occurs during the Moon’s waxing phase” ARISTOTELES

EUDOXUS

ALEXANDER B ALEXANDER A CALLIPUS

ALEXANDER

MARE SERENITATIS

Alexander is a very ancient, very eroded crater, but that doesn’t mean it’s lacking in interesting features

skyatnightmagazine.com 2014

60

Astrophotography Capturing the Geminid meteor shower RECOMMENDED EQUIPMENT DSLR, remote shutter release, fixed tripod or camera tracking mount

ALL PICTURES: PETE LAWRENCE

A composite image can really capture some of the excitement of a meteor shower in full swing

THE GEMINID METEOR shower is a definite highlight for December – as long as the weather plays ball and the Moon doesn’t interfere too much. Actually, even if the Moon is about, meteor photography can still record some great results – just make sure it stays out of frame. The Geminids are active from 4 to 17 December, with this year’s crescendo of activity predicted to occur at 12:00 UT on the 14th. A daylight peak isn’t ideal, but a decent rise to and fall from peak activity should be seen on the nights of 13/14 and 14/15 December. The best time should be on the night of the 13/14th, weather permitting. The Moon will also be about this year: on the night of 13/14 December it’ll be a last quarter phase and rise just before midnight under the rear legs of Leo, the Lion. Although not perfect for visual observation, it shouldn’t cause too much of a problem for photography. The zenithal hourly rate (ZHR) for the Geminids at peak is around 120 meteors skyatnightmagazine.com 2014

per hour – but the ZHR is not the rate you’ll see. The number of meteors you or your camera will see over a given period will be significantly lower. The biggest factor is the sky’s limiting magnitude – that’s the faintest star you can see for the prevailing conditions. Assume you’re watching the shower for an hour centred on 02:00 UT, when the radiant is about 70° up, due south. Also assume that you can see one-third of the sky. With a limiting magnitude of +5.0, the number of meteors you can expect to see is nine per hour. With a limiting magnitude of +6.0, this increases to 23 per hour.

Never mind the Moon While the Moon’s glare will reduce the limiting magnitude for visual observing, a camera tends to record only the brighter trails anyway. Consequently, if the Moon’s in the sky it doesn’t have as much

of a negative effect as you might think. The most important thing to watch out for is that your exposures don’t saturate so the sky becomes white. If you find this is happening with our suggested 30-second exposure time, reduce it accordingly. Geminid meteors are reasonably slow; at most they can be classed as medium speed. The meteoroids that cause the trails enter the atmosphere at 35km/s which, although it sounds fast, is leisurely compared to the 71km/s of November’s Leonids and the 59km/s of the Perseids in August. The consequence of this is that a bright Geminid fireball has a better chance of being recorded in its true glory than an equivalent brightness meteor from a faster shower. This and the high ZHR figure make the Geminid meteor shower the most exciting of the annual showers to try and photograph. This is aided by the fact that from the UK, the radiant gets nice and high in the hours after midnight, when rates tend to be higher because the Earth has turned to encounter the meteoroids head on. Remember that December nights are long and cold. Have plenty of memory for your camera as well as several spare batteries on standby. It’s also worth keeping an eye on the front surface of the lens. If it fogs up, a 12V camping hair dryer can be used to gently clear it.

KEY TECHNIQUE SHOOTING SHOOTING STARS The Geminid meteor shower reaches peak activity on 14 December. It’s an ideal target for meteor photography because the shower offers lots of fairly slow, occasionally bright meteor events. Catching these on camera requires lots of luck, but there’s a fair bit of skill involved too. We’re looking at how to build a composite image of Geminid trails, all pointing back to the radiant. Knowing the right camera settings is important, but so are planning ahead and working out where to point the camera.

Send your image to: [email protected]

THE SKY GUIDE DECEMBER 61

STEP-BY-STEP GUIDE STEP 2

STEP 1 Lens choice is important, and a focal length of 18mm or less is recommended. This will allow you to span a wide area of sky either side of the radiant. The faster the lens the better, but aberrations may occur with some lenses when they are fully open. If this happens, it may be necessary to close the lens aperture by a stop to reduce the effect.

A fixed tripod is fine for this project, but a tracking mount would be even better. This is because with a fixed tripod you will need to move the camera every 30 minutes or so to maintain the relative position of the frame with respect to the radiant. If you don’t do this, the images you’ll produce can still be used but you may find some trails occur outside of the composite area. This problem is eliminated with a tracking mount.

STEP 4

STEP 3 Set the camera to manual mode and turn auto-focus off on the lens. Set the ISO to at least 1600; use 3200 or even 6400 if your camera will allow it and if the noise levels at these settings are tolerable. Focus the lens at infinity. If your camera supports Live View use this on, say, Jupiter and make sure that things are really good and sharp.

STEP 5 Review your images in a program such as the freeware Faststone Viewer, which allows you to flip between shots full-screen. If you find a meteor trail, add the prefix ‘meteor_’ to the file name. Sort the image folder by name to make all the ‘meteor_’ shots appear together. Open one shot in a layer-based editor to use as the master image.

Select large jpeg format and set the exposure to 30 seconds. Align the camera so the frame is horizontal, with the bottom edge parallel to the horizon. Aim to maximise the amount of sky included, avoiding large areas obscured by objects such as trees and houses. Put the camera into continuous exposure mode, and press and lock the remote shutter so the camera takes continuous 30-second exposures.

STEP 6 Open the next image. Select an area around the trail with some stars in it, and cut and paste into the master as a new layer. Make semi-transparent and align the stars. Make opaque and adjust curves to darken the background, then set layer blend mode to ‘Lighten’ so just the trail remains. Repeat for all the meteor shots, flatten and save. skyatnightmagazine.com 2014

CAPTURING A COMET’S

heart Rosetta has finally caught up with its comet and attempted its daring mission to put down a lander. Elizabeth Pearson looks at what comes next

The Philae lander is just one part of the overall Rosetta mission to characterise comets

A deeper understanding Meanwhile, another instrument will send radio pulses between Rosetta and Philae through the comet, analysing the return signal to reveal what the interior looks like, how the layers deep within the comet are structured and how they evolve and change as the comet goes around the Sun. “Each instrument will have a turn at doing something in a predefined sequence,” says Matt Taylor, the ESA project scientist for Rosetta, talking prior to the landing attempt. Once this initial burst of scientific activity has drained the batteries, Philae will use its solar panels to replenish its power. Once fully recharged, the lander will continue with its science routine for as long as possible. >

ESA/ROSETTA/NAVCAM, ESA - J. HUART, ESA/ATG MEDIALAB, ESA/AOES MEDIALAB

A

fter 10 years of racing, Rosetta has finally reached comet 67P/ Churyumov-Gerasimenko. But this is far from the finishing line for the mission – its real objectives have only just begun. As this issue went to press, the most audacious part of the mission – sending the Philae lander to the surface of the comet – had yet to take place. If everything has gone as planned, then on 12 November Rosetta will have given Philae a gentle push towards the comet. This will be the only steering that the lander will get. There’s no sky crane to carefully guide it to safety as Curiosity had on Mars, and the only thruster on board is to force the lander onto the surface, allowing Philae’s feet to screw into the comet to prevent it from bouncing off into deep space. Once touched down and attached to the comet’s surface, there will be no time to admire the view. With only 60 hours of battery life, Philae will have to race through its first science phase, one that started before it even reached the surface. During its descent, Philae’s instruments will take advantage of the opportunity to examine space closer to the comet than Rosetta will be able to

reach on its orbit 10km above the icy body. As well as using its cameras to image the approaching surface, the lander will measure how the magnetic field around the comet changes. Following a successful touchdown, Philae will spend two days measuring every aspect of the comet. Initially, onboard cameras will take a panoramic vista of the craft’s surroundings as well as the surface beneath it. Using these images to select the perfect spot, the probe will rotate and a drill on the base will bore down into the comet’s heart. These samples will then be sent to onboard analysers that will pick apart their composition. Learning what comets are made of is critical to our understanding of how our planet came to be the way it is, as comets are one of the key candidates for bringing not only water to Earth, but also the organic compounds that kick-started life.

64

> “We’ll keep cycling for as long as it can power up,” says Taylor. “But if dust starts covering the solar panels you limit the lifetime of the lander. And there’s always the chance that any part of the surface can suddenly erupt, so there’s a possibility that some activity will push the lander off, but that’s the risk you take when you land on a volatile surface.” Provided it can withstand blinding dust clouds and violently erupting geysers, Philae should survive until at least March. By then the comet will be close enough to the Sun that certain components onboard the lander will begin to fail. But what if it all goes wrong? What if the lander bounces off, hits a boulder or falls into a crevasse? The landing has always been far from certain, relying on equal parts good aim and luck. Though it is Philae that has captured most people’s attention, it is only one of the many instruments that make up the Rosetta mission. “It’s not the end of the world if the lander fails,” says Taylor. “We rendezvoused in August, we’ve been with the comet for over a month, and we’ll be alongside it until the end of next year. It will provide us with a ringside seat as we go through perihelion, the closest approach to the Sun.”

Up close and personal Even without Philae, the spacecraft will continue to circle the comet as it makes its way through perihelion. This is the first time we’ve ever been able to actually follow a comet as it becomes active. Wide-field camera shots have shown that the comet is already beginning to heat up and vent gas into the surrounding space. By the time Philae is due to reach the end of its lifespan in March 2015, the comet will be beginning to build up its two distinctive tails, one made of gas, the other of dust.

Rosetta will use its host of instruments to measure and document every part of the comet as it goes through its journey around the Sun. “The lander will give you something local but the orbiter will give us a global perception of how the comet behaves and what the important parts of the comet are in terms of activity,” says Taylor. Ultraviolet spectrometers will look at the composition of the nucleus and coma, measuring what gases come off the comet. Instruments will analyse the comet’s tail, assessing its shape, speed and composition. Cameras on Rosetta will image the entire surface in the visible and infrared spectrum, to create a full geological map not only of the surface features, but also of which ices make up certain areas. But perhaps the most important thing the orbiter will do is track how the comet changes as it approaches and then goes through perihelion.

Rosetta’s OSIRIS camera has revealed jets of activity along the comet’s entire body

ESA/ROSETTA/NAVCAM X 2, ESA/ROSETTA/MPS FOR OSIRIS TEAM MPS/UPD/ LAM/IAA/SSO/INTA/UPM/DASP/IDA X 6, ILLUSTRATION BY PAUL WOTTON

WHERE TO LAND? Trying to find somewhere to land on an active comet was never going to be easy. But as Rosetta approached comet 67P/ChuryumovGerasimenko, the spacecraft’s OSIRIS camera revealed its unusual shape and the team realised just how difficult their task was going to be. “It was quite a surprise when we saw its shape, but it’s made things more interesting,” says project scientist Matt Taylor. “The main issue in terms of the mission was that it restricted the number of landing sites we had.” The primary concern when selecting a spot was finding somewhere that the lander could actually reach. With no thrusters to steer Philae, there had to be a clear line of sight to the landing spot. “It will be a passive landing – Philae will just be dropped,” says Taylor. “That immediately means we lose quite a swathe of area which we can target. So getting a trajectory that puts Philae near the neck of the comet is near impossible.” Initially the team picked five spots it was thought feasible to land on. After closer

skyatnightmagazine.com 2014

examination, they chose a primary landing sight. “The site that we chose had the best chance of getting all of the science we wanted done,” says Taylor.

J

The team chose landing site J from five original candidates as the best for a passive landing

ROSETTA DECEMBER 65

ROSETTA/PHILAE TIMELINE Over the next year comet 67P/ChuryumovGerasimenko will undergo a huge change as it passes by the Sun. As it gets closer to our star, the comet will begin to heat up, causing the volatile ices that make up its structure to boil and break apart, creating not one but two huge tails that will streak behind the comet – one made from gas, the other from dust. In August 2015 the comet will pass through its closest point to the Sun, called perihelion. Once past this stage the comet will begin to cool and freeze again.

Jan 2014 Feb 2014 Mar 2014 May 2014 Jun 2014

Jul 2016 Jul 2014 Mars

Dec 2015

ty

Aug 2014 Rendezvous

s Toa

Sep 2014 Earth

g k in

Oct 2014

Ba

Oct 2015

ot

Nov 2014 Philae launched

Apr 2015

Baking

n

Co

Jun 2015

ld

Co

ol

But what’s the point of all this research? Why are scientists so keen to analyse every aspect of this comet? “Rosetta will teach us how a comet works,” says Taylor. “That allows you to put that knowledge onto any other comet observation that you’ve made. By characterising this particular comet we’ll be getting an idea of why this does that but this other part doesn’t. These volatiles from the beginning of the Solar System have been trapped there in deep freeze. We’re tapping into material that has been there right from the beginning – by doing that we’ll get a feel for what the conditions were and how we’ve evolved to where we are now.” Though we are regularly passed by these visitors, until now they have remained a mystery. The Rosetta mission and Philae will give us a ringside seat as we watch comet 67P/Churyumov-Gerasimenko undergo its transformation from a cold lump of ice to a glorious beauty streaking through space. S

st y

ze

id

Snapshot of the past

Tepid

To a

o Fr

Aug 2015 Perihelion

Jan 2015 Fr ig

Red h

Dec 2014

“We have an idea of what the nucleus structure is like now,” says Taylor. “After perihelion we’ll be able to do a comparison. We’re going to try and get as close as we can, to learn how the dust lifts off the surface and accelerates to become a real atmosphere. We’ll be able to backtrack and say, ‘This new jet came from this spot. What was special about that spot versus the one 100m to the left?’”

Warm

ABOUT THE WRITER Elizabeth Pearson is BBC Sky at Night Magazine’s staff writer, specialising in space science. She gained her PhD in extragalactic astronomy at Cardiff University.

J

Þ The neck of the comet, as seen by Rosetta’s

OSIRIS narrow-angle camera from 104km away

Þ A close-up of landing site J, located on the crown of the comet’s smaller lobe

J

Þ From 258km away, Philae’s landing site can be seen in the context of the rest of the comet

Þ This purposefully overexposed image, taken from 1,550km, brings out detail of off-gassing

Þ Rosetta snapped this selfie of its 14m solar wing just 16km from 67P/Churyumov-Gerasimenko skyatnightmagazine.com 2014

DAWN OF THE

SUPERSCOPES A new generation of giant telescopes will be put to work over the coming decade. Govert Schilling reveals all…

The 2020s will see three new giant telescopes commencing scientific operations

ou thought the twin 10m Keck telescopes on Mauna Kea, Hawaii, were big? Hold your breath. Astronomers and engineers are working on a new generation of monster telescopes that will see first light within the next decade. On 7 October 2014, a groundbreaking and blessing ceremony at Mauna Kea marked the start of the construction

Y

phase for the Thirty Meter Telescope. At the Steward Observatory Mirror Lab in Arizona, three of the seven mirrors for the Giant Magellan Telescope have already been cast. And on 19 June 2014, the top of Cerro Armazones in northern Chile was flattened to provide space for the European Extremely Large Telescope. Here we take a closer look at these three new giant eyes on the sky that

will usher in a new era of ground-based observational astronomy. > ABOUT THE WRITER Govert Schilling is an astronomer from the Netherlands. He is coauthor of a book about Chile’s telescopes called Europe to the Stars.

FACTS X Mirror size: 30m (made up of 492 hexagonal segments) X Location: Mauna Kea Observatories, Hawaii (altitude 4,050m) X Date of completion: 2021 X Cost: $1.2 billion (£740 million) X Trivia: The innovative, 66m spherical ‘calotte’ enclosure has a circular ‘shutter’, while natural ventilation is provided by 98 vent doors.

This artist’s impression of the TMT clearly shows the laser guiding system

COURTESY TMT OBSERVATORY CORPORATION X 2, LSST, GIANT MAGELLAN TELESCOPE – GMTO CORPORATION, NASA

THIRTY METER TELESCOPE (TMT) AS ITS NAME implies, the Thirty Meter TMT Observatory Corporation in June Telescope will be outfitted with a 30m 2003, together with the Association of mirror. That’s far too big to cast in one Canadian Universities for Research in piece, so the TMT’s primary consists of Astronomy (ACURA). Meanwhile, many 492 hexagonal segments. As such, the US universities and institutes in China, TMT can be regarded as a scaled-up Japan and India have joined the TMT version of the twin 10m Keck telescopes, International Observatory group. which have 36 The TMT is being mirror segments built at Mauna Kea, each. “Development the giant volcano on of the primary Hawaii’s Big Island mirror is our largest that is already home technological to many large scopes, challenge,” says TMT including Keck I, scientist Warren Keck II, Gemini Skidmore. “The North and Japan’s entire observatory Subaru. While the Þ The TMT’s primary mirror consists has been designed Giant Magellan of 492 individual panels with mirror Telescope and the performance in mind.” European Extremely Large Telescope will The California Institute of Technology both be located in Chile, the TMT is the (Caltech) and the University of California only ‘monster scope’ north of the equator. – the same two organisations that built ‘There is ample science for a number the Keck telescopes – founded the of 30m class telescopes,’ says TMT skyatnightmagazine.com 2014

spokesman Gordon Squires. And since TMT is in the north, “Complementary science will be enabled, and the location of these observatories will allow us to explore the entire night sky.” Like its two competitors, the TMT will mainly operate at optical and nearinfrared wavelengths, and capture highly detailed images and high-resolution spectra by using the novel technique of multi-conjugate adaptive optics, which will provide correction for atmospheric turbulence over the telescope’s full field of view. Astronomers expect the TMT to shed light on the early history of the Universe by exploring the very first stars and galaxies that appeared on the cosmic stage, working in close cooperation with the James Webb Space Telescope. The telescope will also study the formation of galaxies, and the role played in this process by supermassive black holes.

ALSO UNDER

CONSTRUCTION The 8.4m Large Synoptic Survey Telescope (LSST), to be completed in 2022 at Cerro Pachón in Chile, will use a 3.2-gigapixel wide-angle camera to rapidly scan the sky three times per week in search of asteroids, supernovae and other transient objects.

SUPERSCOPES DECEMBER 69

GIANT MAGELLAN TELESCOPE (GMT) LIKE THE THIRTY Meter Telescope and the European Extremely Large Telescope, the international Giant Magellan Telescope will have a segmented mirror. But instead of many hundreds of hexagonal pieces, the GMT’s primary consists of just seven 8.4m mirrors – about the largest that can be cast and transported in one piece. The downside of this elegant design is that six of the seven mirrors have to be asymmetric, which makes grinding and polishing a more complicated task. Whereas the TMT is essentially a scaled-up version of the Keck telescopes, the GMT is the logical successor to the twin 6.5m Magellan telescopes operated by the Carnegie Institution for Science at the Las Campanas Observatory in Chile. In fact, says Las Campanas Observatory director Miguel Roth, “We may eventually build a second Giant Magellan Telescope. The platform that we created on Cerro Las Campanas in March 2012 is large enough to house two similar giant telescopes.”

Like the TMT, the GMT has grown into a large international collaboration, with contributions from US universities and institutes, and from organisations in Australia and Korea. The Steward Observatory Mirror Lab of the University of Arizona is developing the telescope’s thin mirrors. They rely on active optics to maintain their precise parabolic shape. In addition to this, adaptive optics will take care of atmospheric turbulence, so that the giant telescope will have 10 times the angular resolution provided by the Hubble Space Telescope. According to Roth, the GMT will already start producing exciting results as early as 2020, with only four of the seven mirror segments and two powerful spectrographs in place. At that time, it is expected to be the largest optical and nearinfrared telescope in existence. A few years later, in its full configuration, it will boast a total light-collecting area of 368m2 – 10 times that of each of the current Magellan telescopes. However, by then it will almost

ALSO UNDER

CONSTRUCTION The NASA/ESA 6.4m James Webb Space Telescope (JWST), the mid-infrared successor to Hubble, is due to be launched in late 2018 and is expected to shed light on the formation of galaxies, stars and planets.

certainly have been surpassed by the Thirty Meter Telescope. Equipped with sensitive spectrographs, the GMT will be a prime instrument for carrying out detailed studies of the chemical composition of stars, mass determinations of supermassive black holes, and measurements of stellar wobbles caused by orbiting exoplanets. >

FACTS X Mirror size: 22.2m equivalent (seven 8.4m segments) X Location: Las Campanas Observatory, Chile (altitude 2,550m) X Date of completion: Early scientific operations will start in 2020, with full capability reached in 2024 X Cost: $1.05 billion (£650 million) X Trivia: While the light-collecting power of the GMT’s seven mirrors will be the same as that of a 22.2m telescope, they will provide the angular resolution of a single 24.5m mirror.

The GMT will be the first of the next-generation superscopes to achieve first light

skyatnightmagazine.com 2014

The 39.2m E-ELT was first planned as the 100m Overwhelmingly Large Telescope

FACTS X Mirror size: 39.2m (made up of 798 hexagonal segments) X Location: Cerro Armazones, Chile (altitude 3,050m) X Date of completion: 2024 X Cost: $1.35 billion (£840 million) X Trivia: The E-ELT’s segmented primary mirror has a total effective surface area of 978m2 – 2.2 times the area of a basketball court.

ESO, PHOTO BY ROB RATKOWSKI. © BY PS1SC. ALL RIGHTS RESERVED

EUROPEAN EXTREMELY LARGE TELESCOPE (E-ELT) DESPITE DOWNSIZING ITS plans over the past 15 years or so, the European Southern Observatory (ESO) will still be building the largest telescope ever. In the late 1990s, engineers came up with an ambitious proposal for developing the 100m Overwhelmingly Large Telescope, but ESO later committed itself to a more realistic 42m instrument, with exactly twice the light-collecting power of the Thirty Meter Telescope. In 2011, budget restraints forced ESO to scale back to a 39.2m primary, consisting of 798 hexagonal segments. According to director general Tim de Zeeuw, the ESO Council has approved the European Extremely Large Telescope programme, even though funding is not yet fully secured. “We’re still awaiting the ratification of Brazil’s ESO membership by the government,” he says. Brazil’s entrance fee is needed to cover a substantial part of the E-ELT’s construction cost. skyatnightmagazine.com 2014

Even though the São Paulo Research Foundation recently partnered with the Giant Magellan Telescope, de Zeeuw is still optimistic, saying, “We expect ratification within a few months.” The E-ELT will be built at Cerro Armazones in northern Chile, close to ESO’s existing Paranal Observatory, which is home to the Very Large Telescope. The mountain top has already been blasted away and construction work on a mountain road is in progress. Located in the central part of the Atacama Desert, one of the driest regions on the planet, Cerro Armazones experiences incredibly clear skies and excellent seeing. A near-infrared camera and a nearinfrared spectrograph have been selected as the telescope’s first light instruments. Three high-resolution imagers and spectrometers will follow. Like the TMT and the GMT, astronomers expect the European monster telescope to shed light

on cosmic evolution and galaxy formation. But its sheer size will also enable detailed studies of nearby Earth-like exoplanets. Then again, as astronomer Martin Harwit once said: “By looking somewhere where no one has been able to look before, one is very likely to make new discoveries.” For all three future telescopes, the greatest scientific excitement will likely lie in the unknown unknowns. S

ALSO UNDER

CONSTRUCTION The Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) project in Hawaii will eventually consist of four extremely powerful 1.8m telescopes equipped with gigapixel cameras. Two of the mirrors have been completed so far.

ADVERTISEMENT FEATURE

ASTRONOMERS’

Gift Guide The Astronomy Centre The one stop shop for a comprehensive range of quality astronomical equipment at some of the best prices. Offering expert advice for all levels of astronomy. Great seasonal gift ideas or treat yourself for the long winter evenings. Telescopes, binoculars, solar scopes, spotting scopes, astrophotography equipment, CCD cameras and accessories from top brands Vixen, Celestron, Lunt, Baader Accessories and Optical Hardware. Call 01223 911150, or email [email protected] for friendly advice and phone orders, or visit www.astronomycentre.co.uk

A Slimline Classic Christopher Ward’s stunning C5 Malvern Slimline watch was launched this year to celebrate the companies 10th anniversary. Working with one of the watch industry’s greatest designers they styled a case that not only houses the compact, hand-wound ETA 2801 mechanical movement but accentuates its slimness with some of the most beautifully subtle lines it is possible to imagine. Only £399. Exclusively available at www.christopherward.co.uk or telephone 0844 875 1515.

Fisher Space Pens Celebrate 45 years since man set foot on the moon with the special ag7-45 edition of the original astronaut pen used on the appolo 11 mission. Finished in blue titanium nitride over chrome the design depicts the commerative spaceflight through a series of streaming stars that encapsulate the historic mission. Fisher space ‘the go anywhere write everywhere’ pen. Pressurised refill technology. Visit www.fisherspacepen.co.uk or telephone 01245 225758.

Astronomy Photographer of the Year: Collection 3 Published by Collins with the Royal Observatory Greenwich, brings together all of the winning entries from this year’s stellar competition. The perfect gift for all stargazers and anyone fascinated by the wondrous sky above, the book showcases over 100 breathtaking images of space and the night sky, from the Horsehead Nebula to images visible from much closer to home. BBC Sky at Night readers can buy Astronomy Photographer of the Year: Collection 3 at £17, saving 30% on the RRP exclusively at Waterstones.com until 19/12/2014. Simply use discount code AS2014 at the online checkout. Image: James Woodend

ADVERTISEMENT FEATURE

Mars

Sega Toys Imagine enjoying the sky full of stars while sitting on your sofa. This dream can become reality with the Homestar Original from Sega Toys. The high definition planetarium with the ultra-bright 3 watt LED and rotating movement projects the Night sky throughout the year. The handy timer lets you fall asleep while gazing at the stars. 2 Discs included more available. Only £99. Visit www.segatoys.eu.

Dark Skies Jewellery To celebrate the Gold Tier Dark Sky status, which has been awarded to 1,500 sq. km. of rural Northumberland by the International Dark Sky Association, the artist has used stunning images of planets, galaxies and nebulas to create a range of jewellery that includes earrings, cufflinks, bangles, pendants, pins and key rings. Each piece comes with a high quality photo card containing information on the reverse. This unique collection of jewellery has been greeted with delight by the star gazing community and would make an ideal gift for Christmas. To see the entire range and buy online please visit: www.darkskiesjewellery.co.uk or telephone 01830 540346.

Galaxy: Mapping the Cosmos By James Geach. “Astrophysicist Geach goes an order of magnitude further than the usual popular astronomy title – those full of breathtaking images, but little in the way of context – by giving readers the fascinating stories revealed by those images: how galaxies are created, how they evolve, and what they tell us about our universe. The sheer variety is stunning... Gorgeous color photos, coupled with clear and engaging explanations of the science behind them, make this book a winner on every level.” – Publishers Weekly. Buy Galaxy at £16, saving 20% off RRP exclusively at reaktionbooks.co.uk using discount code UE9243A.

Io Astronomy Get yourself into Astrophotography this Christmas with iOptron’s very easy to use SkyTracker at just £320, just add your DSLR and tripod! Or, how about their super accurate and lightweight SkyGuider starting at £469, for use with a telescope. Other ideas include Sky-Watcher’s new Star Adventurer, and the amazing AstroTrac TT320X-AG for the ultimate solution. We are experts in small portable astro-imaging gear for DSLR or CCD. Come to our showroom in Clanfield, Hampshire for a demo on these and other brands including Celestron, Lunt Solar and Moonraker, or visit our website: www.ioastronomy.com Telephone: 023 9257 0283.

ASTRONOMERS’

Gift Guide Viking Optical Centres Viking Optical Centres based in Glasgow, Edinburgh and Halesworth are the successors to an old established Scottish astro telescope retailer – Charles Frank. We stock all of the major brands of optical equipment for astronomy, nature observation or for general use.

f1telescopes f1telescopes, your friendly, helpful astronomy shop. If you are just getting started or a veteran stargazer we are here to help with a wide range of telescopes, binoculars, spotting scopes and accessories to suit all budgets. We sell Celestron, Meade, Skywatcher, Vixen, Baader, Lunt, Coronado and TAL, all at some of the most competitive prices available in the UK (Part exchange welcome). Why not give us a call on 01795 432702, browse our website at www.f1telescopes.com or visit our shop in Sittingbourne, Kent. Sky-Watcher Skyhawk 1145P Telescope. Our Price £149 The award-winning 1145P is a great choice for the serious beginner and also receives high marks from more seasoned astronomers. With a useful 114mm of light gathering aperture, combined with its superb parabolic mirror, this telescope is a highly capable all-rounder for the observation of the Moon, bright planets, nebulae, galaxies and star clusters.

Sky-Watcher Heritage-130P FlexTube Dobsonian Telescope. RRP £155, Our Price £139 Sky-Watcher Heritage 130P FlexTube 130mm (5.1”) f/650 Parabolic Dobsonian Telescope. This telescope is an excellent and capable all-rounder which will provide wonderful views of both the Moon and Planets as well as Deep-Sky Objects. The collapsible patented FlexTube™ system has been incorporated making it even more convenient to transport and store.

Visit www.vikingopticalcentres.co.uk, Email [email protected] or phone us on 01986 875315.

Gyroscope.com

Green Witch If you have always wanted a telescope but haven’t known where to go for the best advice, or once had one and now want to get something much more up-to-date, then call or visit Green Witch. Modern telescopes with built-in computers that will find and track thousands of objects are quite affordable. Why not take a closer look? Green Witch was founded by former members of the Royal Greenwich Observatory and offers friendly, expert advice to help you choose and use equipment that is right for you. Call Lee in Birstall, Neil in Gransden, or visit our showroom. Green Witch North 01924 477719 [email protected] Green Witch South 01767 677025 [email protected] www.green-witch.com

Gyroscope.com provides a range of scientific curiosities. From simple toys such as a flip over tops, to more complex obscure things such as a Tesla Turbines, miniature combustion engines, exotic materials with strange properties and of course huge gyroscopes. www.gyroscope.com / 0845 838 1555

Kontax Engineering Ltd - Stirlingengine.co.uk Stirlingengine.co.uk are a British manufacturer of Stirling engines and heat based engines. Many of our engines can run from just the heat of your hand. Our engineering perfection is world renowned. www.stirlingengine.co.uk [email protected]

ASTROLOGY AN ASTRONOMER’S VIEW

Astrology and astronomy were once the same discipline but, as Alister Graham explains, science has since moved on

ASTROLOGY DECEMBER 75 The Babylonians believed that Mars’s appearance in the night sky heralded the onset of war

The ancient Egyptians also believed that their Sun god Ra was swallowed every night by the sky goddess Nut, then reborn the following day. Night fell when Nut returned to, and embraced, the Earth god Geb, her star-studded body creating a canopy over the Earth. Storms during the day were thought to occur when Nut came close to Geb, and Geb’s laughter was thought to be the origin of earthquakes. The ancient Greeks further developed the system of correspondences that linked people with the heavens. It was Aristotle’s endeavour to mathematically describe this magical world view that led to what we know today as astrology.

A

sk any astronomer if they believe in the ancient practice of astrology and the answer will likely be a resounding no. And yet the science of astronomy had its origins in this astrological belief system, which goes back a long way. Perhaps not surprisingly, early civilisations regarded the stars and planets as evidence of supernatural powers that could magically affect their lives. From the writings of Babylonian priests, we know that they would ‘interpret’ various astronomical events as omens. Using their ‘principles of analogy’ or ‘laws of correspondence’, the Babylonian priests would claim to foretell the future state of affairs of their kings based on the positions of celestial bodies. For example, a red-coloured Mars was a sign of blood and imminent war; a stellar constellation resembling two fish referred to water. By the time of the Egyptian empire, the messages in the heavens weren’t just for the rich and powerful – the stars and planets now held advice for everyone. Egyptian astrologers would provide horoscopes founded on the belief that the instant of one’s birth established one’s character and disposition. With such

an increased customer base and the new personal connection to the heavens and the gods, which was previously only for the elite, it’s easy to see why astrology and the production of horoscopes flourished.

The Greeks meshed the Egyptian system of attaching significance to the angular distance separating the Moon and planets from the Sun with the Babylonian zodiac. The zodiac shows which constellation the Sun, and thus the powerful Sun god, appears to reside in. It also dictates one’s ‘star sign’. The Greeks believed that the relative proximity of the Sun god to the other ‘gods’ (planets) at the time of one’s birth influenced one’s personality. Similarly, the association of the Sun god with a particular constellation determined our character. Further modifications came from the Romans, notably Ptolemy in the second century AD, perhaps best known for mistakenly believing Earth was the centre of the Solar System. As astrology developed, each star sign came to have a fictional creature or figure >

In ancient Egyptian lore, Geb the Earth god was blanketed at night by Nut the sky goddess

skyatnightmagazine.com 2014

THINKSTOCK X 2, © IVY CLOSE IMAGES/ALAMY X 2

Greeks and Romans

Aries

Leo

Sagittarius Scorpio

Capricorn

Pisces Libra

Aquarius Virgo

Taurus

Cancer

Gemini The 12 constellations that make up the astrological zodiac > associated with it, whose form was traced out by the brightest stars of a constellation. Those born under the water sign Pisces are supposed to possess a love of the sea and have numerous skills connected with water and rivers, the flowing nature of which is claimed to make Pisceans adaptable to changing situations. They are also said to have a certain degree of dualism due to the presence of two fish in this constellation and are thus compassionate to others’ points of view. To give other examples of how these so-called laws of correspondence work, those born under the sign of Leo are Stars in a given constellation appear to be close together, but are often vast distances apart

skyatnightmagazine.com 2014

said to be proud, forceful leaders; those born under Aries are allegedly headstrong and impulsive; Geminis have split personalities, are social and good communicators; Taureans have a plodding, patient, stubborn nature; while Scorpios are self protective. Astronomy and astrology used to be intertwined: Galileo (1564-1642) and Kepler (1571-1630) were expert astrologers. But as the forces of nature and the distances to the stars and planets were better understood, astrology shifted into the realms of pseudo-science. Today we know that there is no significant interaction

between the Sun and the stars that define the constellations – the distances involved are simply too vast. Moreover, even the stars of the constellations themselves often have no physical association with each other, only appearing to do so when viewed from Earth. So the constellation Pisces, once connected with the Babylonian goddesses Anunitum and Simmah, the Syrian goddess Ashtarte, and the Greek goddess Aphrodite and her son Eros, is simply a scattering of self-gravitating nuclear fusion reactors – stars – spread across the Milky Way.

Gravitational force But are there any known forces exerted by the stars and planets that might affect us? Gravity and electromagnetism are the only possible candidates, yet they are so weak as to be negligible. At the time of our birth, the obstetrician exerts a greater gravitational force on us than the planets and constellations, and a fridge magnet has a stronger electromagnetic influence. Moreover, variations in solar flares result in the Sun’s magnetic influence on Earth changing randomly from day to day, and at a level greater than that coming from the planets and stars. And the lights of a hospital operating theatre, or even local TV and radio stations, produce more radiation than that which arrives from space.

ASTROLOGY DECEMBER 77

It therefore comes as little surprise, especially given that traits are supposedly based on those of mythological creatures in the heavens, that modern statistical studies using large numbers of people have shown no evidence that constellations or planets provide any insight into individual personalities. Marriage and divorce rates show no correlation with allegedly compatible and incompatible ‘signs’. Scientists of every sign exist in equal numbers, as do entertainers and military personnel; there is no tendency for any of them to be of a particular star sign. In 2003, Australian scientist and former astrologer Geoffrey Dean, and Ivan Kelly, a psychologist at the University of Saskatchewan in Canada, presented a study of over 2,000 ‘time twins’ born in London. People born at the same time should, according to astrology, have very similar personalities. However, the study found no evidence of any more similarities between ‘time twins’ than between any randomly selected pair of people. In another study, Dean asked 22 people to rate the accuracy of their astrological readings, but switched the phrases in half of these with their exact opposite meaning. Those who received the reversed readings rated them just as highly as those who received the unmodified horoscopes. And in 2007 David Voas examined the birth dates of 10 million married couples in England and Wales. If people of a certain zodiac sign are indeed particularly compatible, then one would have expected to see this reflected in the star sign of their partner – yet the results revealed no such pairing.

Þ Joan Quigley, who passed away in October 2014, acted as astrologer for US President Ronald Reagan following an assassination attempt

Þ Variations in solar flare activity have a greater influence on Earth than planetary motions

which claim to help us find solutions. Who to date? Who to employ? Spend or save? In 1966 the number of births in Japan fell by over 25 per cent as couples avoided giving birth in the year of the ‘Fire Horse’, which comes around every 60 years and is said to result in daughters with such monstrous egos and lack of family loyalty that they bring bad luck to the father and future husband. It was heavily publicised in 1988 that former US President Ronald Reagan would plan his schedule around the writings of Joan Quigley, a San Francisco astrologer. More recently, the US National Science Foundation (NSF) Science and Engineering Indicators study from 2014 reported that a whopping 45 per cent of Americans think that astrology is either ‘somewhat’ or ‘very’ scientific. It’s a similar story in India, where many people, including top politicians, are reported to still consult with astrologers, in particular for the optimal timing of key private and public events. In contrast, the NSF report noted that only eight per cent of Chinese people believe in horoscopes. Astrology’s enduring appeal, despite its lack of any scientific foundation, says more about human psychology than it does about the power of the stars. S

“At the time of our birth, the obstetrician exerts a greater gravitational force on us than the planets and constellations” So is there a plausible explanation for belief in horoscopes? One might be that, in general, they are often vague. This might explain how they succeed in making some people believers: when readings give specific predictions, subjects tend to forget those that didn’t come true, but concentrate on those which seem accurate.

Popular appeal Vast numbers of individuals and businesses base important professional and personal decisions on advice received from astrologers and daily horoscopes,

ABOUT THE WRITER Prof Alister Graham researches the structure and dynamics of galaxies, and teaches through Swinburne Astronomy Online.

skyatnightmagazine.com 2014

THINKSTOCK X 2, SEBASTIEN BEAUCOURT/LOOK AT SCIENCES/SCIENCE PHOTO LIBRARY, SOHO/NASA/ESA, REX/SIPA PRESS

Þ If astrology is to be believed, then more married couples should have purportedly ‘compatible’ star signs – but this is not the case

SKILLS

Brush up on your astronomy prowess with our team of experts

78 80 83 85

THE GUIDE HOW TO SKETCHING SCOPE DOCTOR

The Guide

The cosmic microwave background With Elizabeth Pearson

The ancient light that could help explain how the Universe began

This Planck image of the CMB is the most detailed yet created

ARCHIVES/AMERICAN INSTITUTE OF PHYSICS/SCIENCE PHOTO LIBRARY

ESA AND THE PLANCK COLLABORATION X 2, NASA X 5, EMILIO SEGRE VISUAL

T

he entire Universe is awash with microwaves. The CMB, or cosmic microwave background, is an undercurrent of radiation coming from every direction of space. It is critical to understanding how the cosmos was created and is regularly cited as one of the most important astronomical discoveries of the last century. But where did this ever-present radiation come from? In the first hundred thousand years after the Big Bang the entire Universe was filled with plasma, a dense fog so hot that atomic nuclei had their electrons were ripped away, creating an ionised gas. These particles began to glow white-hot, but ionised gas is very good at absorbing light, so any light created was almost instantly absorbed when it hit an atom. Even though the Universe was alive with light, it was so short-lived that you couldn’t see it. That all changed 380,000 years after the Big Bang. At this point the Universe had skyatnightmagazine.com 2014

cooled to the extent that particles in the plasma could capture electrons again. Once that happened, the light wasn’t being absorbed any more. Now that there was nothing to stop this light, it began to travel out in every direction. This is called the ‘surface of last scattering’. Much of that light has continued travelling for nearly 14 billion years. As space has expanded this light has also stretched out, and its wavelength increased until it reached the microwave region. It is this light that we see today as the cosmic microwave background.

Strange anomalies At first glance the CMB is the same in every direction, a constant undercurrent of microwave radiation at around 4°C above absolute zero. However in 1992, NASA’s Cosmic Background Explorer (COBE) became not only the first survey to cover the whole sky, but also mapped the CMB

more precisely than ever before. In doing so, it found that the sky was actually covered in blobby variations, called ‘anisotropies’, and these have been a big problem for cosmologists. If the Universe was created as the Big Bang theory suggests, then it should have expanded in a completely uniform way. This would mean that the CMB should be the same in every direction – but that’s not what was observed. Either the theory had missed something, or everything cosmologists thought they knew about the beginning of the Universe would have to be reconsidered. Luckily, the former was true: the anisotropies could be explained. In the first few moments after the Big Bang, ‘quantum fluctuations’ caused tiny uneven spots to appear throughout the Universe. As space rapidly expanded, these miniscule fluctuations grew to the size of galaxies and even larger. There have been many telescopes since COBE that have mapped the sky in even

THE GUIDE DECEMBER 79

HOW WAS IT DISCOVERED? Although the CMB was first theorised in the 1940s, it wasn’t discovered until 1964 – and then only by accident. At Bell Telephone Laboratories in New Jersey, Arno Penzias and Robert Woodrow Wilson were using a 6m horn-shaped antenna to look for radio signals between galaxies, but when they first began observing they noticed a constant background noise coming from every direction. They attempted to explain the noise, citing urban interference, contamination from the Milky Way and even pigeons nesting in the antenna, but one by one each was discounted. It wasn’t until the pair were contacted by Robert Dicke from Princeton University, who was about to build his own dedicated CMB detector, that they

realised what they had found. In 1978 Penzias and Woodrow shared a Nobel Prize in honour of their serendipitous discovery.

Wilson, Penzias and the Holmdel horn antenna with which they discovered the CMB

IMAGING THE CMB

The view of the CMB from Earth is greatly affected by the motion of our Galaxy through the Universe; it’s redshifted. The red area at the top right of the image above is the region of sky the Milky Way is moving away from. The blue is the area it’s moving towards.

Each new generation of spacecraft has revealed more detail in the CMB. From top: COBE, 1992; WMAP, 2003; Planck, 2013

greater detail. Ground- and balloon-based scopes have concentrated on specific areas, but to really understand the CMB requires a map of the whole sky. In the early years of the 21st Century, the WMAP satellite repeated COBE’s all-sky map, but with a much higher resolution. More recently, the Planck satellite has mapped the CMB to a greater precision than ever before. In the coming years and decades, it will be exciting to learn what new realms of research this fascinating field opens up. S Elizabeth Pearson is staff writer for BBC Sky at Night Magazine

The effect of this redshift can be easily removed from the image using specialist software, revealing small fluctuations. However, there is still a huge, bright swathe across the middle. This is caused by contamination from dust in the Milky Way.

Once the effect of our own Galaxy has been completely removed, the fluctuations across the sky become clear. One of the biggest mysteries of the CMB is the ‘cold spot’, circled in the image above, a region seemingly devoid of radiation and currently without explanation.

skyatnightmagazine.com 2014

SKILLS

How to Build a Dobsonian mount With Steve Richards

PART 1

Turn a sheet of plywood into the building blocks of a great mount

TOOLS AND MATERIALS

POWER TOOLS

A plunge router for cutting the circular components of the mount; hand drill with 1.5mm and 2mm bits to make pilot holes. TAPE MEASURE AND PENCIL

Accurate measurements are essential for making sure that the mount assembles to a tight tolerance. TELESCOPE

This project assumes that you own or are going to acquire a Newtonian reflector tube with an 8-inch or greater aperture, as well as suitable tube rings and a pair of dovetail bars. WOOD

The finished mount – this design can be modified for any 8-inch or larger Newtonian telescope

he Dobsonian telescope is simplicity itself: a Newtonian reflector mounted on a basic altaz mount. Many thousands of astronomers have constructed their own Dobsonians, but the satisfaction of building your own mount is immense – and it’s this we’re going to cover in this two-part project. The dimensions of our design are based on a 10-inch Newtonian reflector but you can work out what size components you need for any Newtonian with an aperture of 8 inches or more using the ‘Calculations’ spreadsheet supplied via the link at the end

ALL PICTURES: STEVE RICHARDS

T

skyatnightmagazine.com 2014

of this article. The mount is made from 18mm plywood, which has great strength and warp resistance. We chose to use cheaper ‘Far Eastern’ plywood and give it a painted finish. Alternatively, you could opt for a natural wood finish if you use the more expensive Birch plywood; this wood has a nicer grain, with fewer knots and blemishes, which gives a better result when varnishing. Apart from a plunge router, you only need standard tools and sundries. A full list, including all the bolts and screws needed for part 2, is included via the link. To begin the build, enter the nine dimensions required in the yellow boxes

External-quality 18mm plywood is ideal for this project as it is strong and warp resistant; make the router jig out of 3mm MDF.

of our Calculations spreadsheet. This generates the sizes for the wooden parts you need in the blue boxes. Transfer these figures to a diagram similar to the ‘Cutting Template’ (supplied via the link), allowing an extra margin for the altitude bearing wheels (see Step 3) and ask your timber merchant to cut the sheet for you. You should end up with six pieces: two equal squares for the base board and rocker box base, one short rectangle for the rocker box front, one long rectangle (we’ll use this to make the box’s sides) and two larger

HOW TO DECEMBER 81

squares for the altitude-bearing wheels. Note that the ‘Tube to Altitude Bearing Ratio’ in the Calculations spreadsheet defines how large the altitude-bearing wheels will be. Anywhere between 1.5x and 1.8x is fine, with larger wheels resulting in smoother operation.

STEP-BY-STEP GUIDE Foot mounting holes

Creating a jig The figures produced in the red boxes in the Calculations spreadsheet are to help you make a circle-cutting jig for use with the plunge router. This jig is vital to turning the square altitude-bearing wheel ‘blanks’ into circles. First, cut a piece of 3mm MDF board to the dimensions given in Step 2, then mark and drill 2mm holes in the jig at positions ‘a’ to ‘e’, as indicated by the numbers in the red boxes. Note that these positions are measured from the inner edge of the router bit. Replace the router’s foot with this jig, then push a 2mm round nail through position ‘a’. Place one blank on the table, mark its centre, then drill a small pilot hole. Place the router and jig on the board, then tap the nail into the pilot hole. Start the router and plunge it down by just 3mm, then lock it and slowly rotate it around the nail in a complete circle. Plunge it down a further 3mm and cut a deeper circle. Continue until you have cut through the full thickness of the board, then repeat for the second blank. You now have two circles. Follow one of the lines passing through the centre and mark the one- and three-quarter points; drill pilot holes on them. Then cut two holes in each wheel, with the pilot holes at the centre and the nail in the jig at position ‘c’. Keep the two best cut-out discs for use as ‘retainers’ later on. Altitude-bearing wheel complete, we need to make the sides of the rocker box. Mark the centre of the side panel sheet (the long rectangle), drill a pilot hole, then move the nail in the router jig to position ‘b’ and cut out another circle. This time the circle will be incomplete, leaving you with two rocker box sides with one scalloped edge. Mark the centre of each side and use the router to cut out further circles using position ‘e’. Finally, cut a rectangular piece of ply 50mm deep by the width of the rocker box base for use as a brace. Next month, we’ll put them together and finish off the mount. S Steve Richards is a keen astro imager and an astronomy equipment expert DOWNLOAD THE PROJECT FILES Visit this link for the calculations spreadsheet, cutting list and more http://bit.ly/DobMountPt1

b d

e

a c

STEP 1

STEP 2

Determine the telescope’s balance position with your heaviest eyepiece installed and decide what clearance you want at the base of the scope. Use the Calculations spreadsheet to draw up a template for your timber merchant and get the parts cut out.

Remove the plunge router’s foot and use it as a template to cut the circle-cutting jig: its length should be 450mm, its width the same as your router. Mark the jig using the figures in the red boxes on the Calculations spreadsheet and drill 2mm holes in these positions.

STEP 3

STEP 4

Carefully mark the centre of each square altitude-bearing wheel blank by drawing a line diagonally from opposing corners to form a cross at the centre. Attach the router by aligning a 2mm nail through the jig into a pilot hole at the centre and rout a circle.

Pick one of the two altitude bearing wheels cut out by the router, choose one of the diagonal lines and mark the one- and threequarter points. Drill pilot holes for the cut-outs then re-position the nail in the jig and rout out the two holes. Repeat for the other wheel.

STEP 5

STEP 6

Select the side panel sheet and carefully mark the centre by drawing lines from opposing corners. Attach the router by aligning a 2mm nail through the jig into a pilot hole at the centre and rout two ‘half moons’.

Mark the centre of the two side panels you produced in Step 5 with lines from opposing corners again to form a cross at the centre. Attach the router by aligning a 2mm nail through the jig into a pilot hole at the centre and route a circle.

skyatnightmagazine.com 2014

PORTABLE POWER THROUGH THE NIGHT

Mobile Solar Chargers have a unique range of portable power banks, both with or without solar backup. They are suitable as power on the go for all mobile phones, tablets and most portable devices, hold their charge for months and can be recharged by the mains, USB and of course solar. The range starts from £14.95.

10% discount off code : MSCEMP

www.mobilesolarchargers.co.uk [email protected]

SKILLS

SKETCHING DECEMBER 83

Sketching Christmas Tree Cluster With Carol Lakomiak

NEED TO KNOW NAME: The Christmas Tree Cluster, NGC 2264 STEP 1 Centre the cluster in your eyepiece. Using a B pencil, draw the stars that form the basic outline of the tree, plus a few ‘framing stars’ (see text) to the west. The cluster’s northernmost star, 15 Monocerotis, is a bright magnitude +4.7, so make this larger than the other stars.

TYPE OF OBJECT: Open cluster CONSTELLATION: Monoceros RA: 06h 40m DEC: +09º 53’ EQUIPMENT: 4-inch refractor (or small reflector); B and H pencils BEST TIME TO SKETCH: 20-31 December, 18:00 UT to 22:00 UT FIELD OF VIEW SHOWN: 65 arcminutes; 67x magnification

ALL PICTURES: CAROL LAKOMIAK

N

GC 2264 is a large, scattered open cluster that’s located in the northern section of Monocerotis, about 3º southsouthwest of mag. +3.4 Alzirr (Xi (j) Geminorum), and is bright enough and big enough (nearly 0.5º long) to be seen through a finderscope or binoculars. William Herschel entered it into his catalogue in January 1784, and it was nicknamed ‘the Christmas Tree Cluster’ by Leland Stanford Copeland. The famous Cone Nebula extends southward from the ‘tip’ of the arboreal cluster. Before starting your sketch, choose an eyepiece that’s wide enough to show the entire cluster at once, nestled comfortably in the surrounding field of stars. The framing stars mentioned in Step 1 are quite important if your telescope does not have an automatic tracking function. This is because Earth’s rotation makes things continually drift out of your field of view, and framing stars act as guides when you’re readjusting your telescope to compensate for this drift. To accurately re-centre the telescope, make sure the framing stars in the eyepiece are in the same place they were when you added them to your sketch.

The stars you draw in Step 1 are ‘anchor’ stars – the foundation of your sketch – and need to be placed as accurately as possible. So before beginning to sketch, study the cluster for things that might help you. For example, when the cluster is centred in the eyepiece, 15 Monocerotis (the brightest star) is centred in the east-west axis, but lies north of the north-south axis. Also notice the cascade of stars forming the eastern side of the ‘tree’ and the pairs of stars at both the top and bottom of it. After studying the cluster, begin to draw the anchor stars – lightly at first, in case you make any mistakes. After you’re satisfied with their placement, go back and darken them, remembering to make the brightest stars the largest, as you see them on star charts. Complete your sketch by adding the remaining stars; use the anchor stars and the sketching circle’s border as reference points to help determine their placement. Familiar shapes or patterns in the star field will also help you to accurately draw stars in relation to one another. Use averted vision to detect very faint stars. Carol Lakomiak is BBC Sky at Night Magazine’s sketching expert

STEP 2 Use the B pencil to start populating the star field. First draw the stars that surround the cluster, then add the stars in the outline of the tree. Keep your pencil sharp when drawing dim stars – a blunted pencil creates bloated stars that turn out larger than intended.

STEP 3 Using an H pencil, add the faintest stars – your aperture will determine your limit. Start by looking at one of the previously drawn stars, then scan the area around it using averted vision. Be patient and wait for the moments of better seeing that allow you to detect them.

skyatnightmagazine.com 2014

SKILLS

SCOPE DOCTOR DECEMBER 85

Scope

With Steve Richards

DOCTOR

Our resident equipment specialist cures your optical ailments and technical maladies

Is there an easy way to check that the secondary mirror in my Sky-Watcher 200P is properly centred? DAVID BURLINGTON Sometimes astronomers have to disassemble their telescopes in order to flock the inside, or perform similar maintenance. As you would expect, after putting it back together a full collimation will be required, as every element that controls the course of the light through the telescope will have been disturbed. There are two possible causes for the secondary mirror appearing to be off-centre: either the focuser or the mirror may not have returned exactly to their original positions. Unless on closer inspection the focuser is obviously

wrongly positioned, make all your adjustments to the secondary mirror. Cheshire eyepieces are excellent all-round collimation tools but for centring the secondary mirror, you may well find that a simple collimation cap will allow you to see the edge of the focus tube more easily. These can be bought for around £5, or you can make your own using an old plastic film canister with a small hole drilled in its centre. Mask the light from the primary mirror, form a backdrop behind the secondary mirror with an L-shaped folded sheet of white paper and insert the collimation cap in the focuser’s eyepiece holder. Looking through the small hole, you should have a clear view of the position of the secondary mirror in relation to the focus tube, allowing you to adjust the position of the mirror until it has an even, circular margin around it.

< Use a collimation

cap to centre a secondary mirror

STEVE’S TOP TIwarPm during

What’s the best way to keep cold winter observing sessions? long nights of With winter upon us the prospect of e long nights thos but observing is very appealing, warm is ing keep to key can be very cold. The mal ther don to id afra be t layers, so don’ jumpers, underwear, a shirt, a couple of light always a is hat a fleece and gloves. A woolly vacuum a g alon g takin good idea, too, as is popular with are ets sach gel r’ rme flask. ‘Handwa to get more many astronomers, but if you want Warmawear ding high-tech, several suppliers inclu will that les inso ed heat and Greenfingers sell ty. toas and nice keep your feet

Can you recommend a good ‘grab and go’ telescope in the 8-inch range? PETE WILLIAMS It’s clear from your full question that you are looking for a system to complement your Meade 300mm ACF Catadioptric, which is destined to become an observatory-based telescope for astrophotography. As you have already discovered, even though the Meade is described as ‘man portable’, this means different things to different people, but for any kind of astrophotography you do need a stable mount. As you have already chosen a long focal length telescope, it would make sense to suggest something along those lines but as an alternative, a shorter focal length instrument should also be considered. The Celestron C8 Edge-HD VX GoTo would make an excellent choice to mimic the optics of your larger, coma-corrected telescope on a portable scale, with a manageable yet substantial mount. As an alternative with a shorter focal length, the Sky-Watcher Explorer 200P HEQ5 PRO is also very manageable but sturdy, and is better suited to deep sky imaging. Steve Richards is a keen astro imager and an astronomy equipment expert

PAUL WHITFIELD X 2

Celestron’s C8 Edge-HD scopes have excellent optics

Email your queries to [email protected] skyatnightmagazine.com 2014

The Widescreen Centre 'RUVHW 6WUHHW /RQGRQ : 8 1' %DNHU 6WUHHW


4XDOLW\

&KRLFH

([SHUWLVH

6HUYLFH

Since 1958

Arguably the world’s premier marque and most desirable telescope. Questar have been in continuous production since 1950 and is now available from The Widescreen Centre. Standard model 3.5” shown from £3,999.00

At Widescreen now.

From £199.00

NEW from Bisque Paramount MyT Portable Hands Robotic Up Mount

NEW Daystar Quark ‘H-Alpha Eyepiece’

Everything you hear about The Quark Ha ‘eyepiece’ from Daystar is true. And It’s available now at Widescreen.

World famous, world class Brandon eyepieces & 2.4x Dakin Barlow from Vernonscope. Standard equipment on Questar telescopes. Precision, hand-crafted eyepieces. Get the very best from your telescope.

As reviewed by Pete Lawrence

Who Wants One

£ TBC Expect circa £5K

0( SHUIRUPDQFH %HOW GULYH JHDUV NJ FDSDFLW\ +HDG NJ 6N\; 3UR 73RLQW 0DF 3&

In stock from £799.00

Widescreen Knows

“The Best Astronomy Software”

William Optics Introducing the NEW 5-element William Optics Star 71 Imaging OTA Available Now at Widescreen

.0

t v7 sias u h t £89 t En Nigh vailable y r r a Sta Also

‘The best scope we’ve ever made’ - William STAR-71mm f/4.9 Imaging OTA with FPL 53 glass. 5 elements, 3 groups, 45mm imaging circle. 2.5” focuser - M48 thread & Canon EOS adapter. Includes mounting rings and Vixen style dovetail. Weighs 2.4 kg with tube rings & dovetail. Optional dedicated 1.25” dielectric diagonal. An optional soft carry case is available separately. See the Star-71 at Widescreen’s events including Astrofest 2015 (Feb 6-7) and the monthly BSIA meetings. William Optics Star-71 from £799.00

Great deals on all Meade scopes Call us on (020) 7935 2580 today

£149 9

£249

KHUH QRZ IURP 6LPXODWLRQ &XUULFXOXP (QWKXVLDVW 3UR 3UR 3OXV

LX200 10” ACF OTA - call

Star Adventurer Available Now! NEW Sky-Watcher ‘Star Adventurer’ Multi-purpose mount. Stunning value from £219.00 (Shown here with Equinox 80ED) Full ‘Astro Photo’ Package incl. Counterweight, Shaft & Wedge £299.00 Call Widescreen on (020) 7935 2580

Sadr image courtesy Geoffrey Lenox-Smith

'RUVHW 6WUHHW /RQGRQ : 8 1' %DNHU 6WUHHW ZZZ ZLGHVFUHHQ FHQWUH FR XN

VLPRQ#ZLGHVFUHHQ FHQWUH FR XN

-RLQ 7KH :LGHVFUHHQ &HQWUH DQG WKH %6,$ LQ 5HJHQW¶V 3DUN WKLV winter. VXPPHU ,W¶V IXQ LW¶V IUHH DQG LW¶V IRU HYHU\RQH

)RU %6,$ ;PDV 3DUW\ GDWH VHH RXU ZHEVLWH :LGHVFUHHQ VXSSRUWV 7KH %DNHU 6WUHHW ,UUHJXODU $VWURQRPHUV &KDQFH WR FKHFN RXW RXU SURGXFWV DIWHU GDUN 6HH www.bakerstreetastro.org.uk IRU PRUH GHWDLOV

The best telescope advice in the industry - try us! The UK’s Tele Vue showroom

The Widescreen Centre News & Events NEW Hotly Anticipated Damian Peach DVD Is Here! -only from Widescreen-

The Widescreen Centre 47 Dorset Street London W1U 7ND Tele Vue always in stock Delos £295 £256

Ethos 13 £525 £479

Whether it’s an Ethos or a Delos, a scope for travelling or a Powermate IRU WKLVH XS FORVH SODQHWDU\ VKRWV \RXOO ¿QG LW LQ VWRFN DW :LGHVFUHHQ SkyFi USB & SkyWire: control your Goto telescope from your iPad! Download SkySafari from the App Store (rated one of the best Apps - period).

StarBlast 62 £339 StarBlast 4.5” £199 9x50 RA CI £89 50mm guide £297 SkyFi £149.95 SkyWire £59.00

Available Now £22.99 Learn from the Master! Merry Christmas to all! Widescreen will be open until 1pm on Xmas Eve reopening January 5th. Emails to [email protected] will be monitored during the closure. Last sendouts:Courier: Friday 19th Royal Mail: Monday 22nd. Remember we’re open late Thursdays to 7pm. Need a gift idea?... Personalised Gift Vouchers

The full range of Astronomik & Gerd Neumann products is available at Widescreen. Call us for advice & check stock.

On Display in store at Widescreen! Valid 1 year, any amount. ‘Widescreen Telescopes Centre’ App

1.25”, 2”, EOS-Clip Full Frame

6” £ 8” £ ´£ Download for FREE today...

'RUVHW 6WUHHW /RQGRQ : 8 1' %DNHU 6WUHHW ZZZ ZLGHVFUHHQ FHQWUH FR XN

VLPRQ#ZLGHVFUHHQ FHQWUH FR XN

PLANET EARTH EDUCATION

A popular and long standing provider of astronomy distance learning courses. All courses enjoy an excellent reputation and a certificate is awarded for each completed course. Students have easily accessible, one-toone contact with their tutors. Five astronomy courses available: - GCSE Astronomy - for a certificate - PEC Nature of the Planets - learning for fun about the solar system - PEC Nature of the Stars - learning for fun about the night sky - PEC Astronomy - to GCSE standard but without the exam - PEC Advanced Astronomy - for the more dedicated student Also available: The Mobile Stars Planetarium – an exciting educational experience for children in schools and for scouting groups.

Enrolment throughout the year 0161 653 9092 | www.planeteartheducation.co.uk

REVIEWS DECEMBER 89

Reviews Bringing you the best in equipment and accessories each month, as reviewed by our team of astro experts

HOW WE RATE Each category is given a mark out of five stars according to how well it performs. The ratings are:

+++++Outstanding +++++Very good +++++Good +++++Average +++++Poor/Avoid

90

Find out how Celestron’s Cosmos 90GT takes full advantage of smart tech

SEE INTERACTIVE 360° MODELS OF ALL OUR FIRST LIGHT REVIEWS AT WWW.SKYATNIGHTMAGAZINE.COM

This month’s reviews First light

90

Celestron Cosmos 90GT Wi-Fi telescope

94

Olivon 10x50 QB binoculars

98

Starry Night Pro Plus 7 planetarium software

WWW.THESECRETSTUDIO.NET X 4

Books

102

We rate four of the latest astronomy titles

Gear

104

Including this Explore Scientific HR coma corrector

Find out more about how we review equipment at: www.skyatnightmagazine.com/scoring-categories skyatnightmagazine.com 2014

90

FIRST light

See an interactive 360° model of this scope at www.skyatnightmagazine.com/celestwifi90gt

Celestron Cosmos 90GT

Wi-Fi telescope A beginner scope brought into the 21st Century WORDS: PAUL MONEY

WWW.THESECRETSTUDIO.NET X 3, PAUL MONEY X 3, COPYRIGHT © 2014 APPLE INC. ALL RIGHTS RESERVED X 3

VITAL STATS • Price £399 • Optics Refractor • Aperture 90mm (3 inches) • Focal length 910 mm (f/10.1) • Mount Computerised single fork arm (altaz) with integrated Wi-Fi network. • App Celestron Cosmos Navigator or SkyPortal (£free, available for iOS and Android, must be downloaded separately) • Extras 25mm and 10mm eyepieces, star diagonal, StarPointer red-dot finderscope, accessories tray with smartphone/ tablet holder. • Weight 7kg • Supplier David Hinds • www.celestron.uk.com • Tel 01525 852696

C

elestron’s Cosmos 90GT is a beginners’ telescope with a twist – there is no handset. That’s because this system is specifically designed with smartphone and tablet users in mind. The scope is supplied with 25mm and 10mm eyepieces, a star diagonal (all 1.25-inch fit), StarPointer red-dot finder, a battery pack for eight AA batteries, which we found lasted for the entire review period, and a Cosmic Calendar poster. This instrument was produced in association with Cosmos: a Spacetime Odyssey, the TV successor to Carl Sagan’s original Cosmos: a Personal Journey in the 1980s. The logo of new series, which was fronted by Neil DeGrasse Tyson and broadcast earlier this year, appears on the telescope tube; the single arm mount, meanwhile, is based on the show’s fictional ‘Spaceship of the Imagination’. Its red lights come on when the scope’s Wi-Fi is active. Assembly was very easy, requiring no tools, and within a few minutes the telescope was ready for use. The primary 3.5-inch lens is fully coated, and gave lovely views of both bright deep-sky objects and the Moon. The scope has a focal length of 910mm and a focal ratio of f/10.1, which give magnifications of 36x with the 25mm eyepiece and 91x with the 10mm.

SKY SAYS… Using your smartphone or tablet to operate the Cosmos 90GT couldn’t be simpler

The lack of a handset makes this instrument appear a little strange, as there is no way to manually move the scope in either axis – but that is the point of this system. The Cosmos 90GT takes full advantage of smart technology using purposebuilt apps. However, there is an aux port on the mount that allows you to connect a NexStar handset (sold separately), which provides an alternative method of control if you don’t own a smart device. Note that without either there is no way to operate this scope.

Getting online We found it easy to connect to the built-in SkyQLink Wi-Fi network and download the recommended Cosmos Navigator app (free; available for iOS and Android) The app acts like a planetarium program and is a ‘lite’ version of Celestron’s SkyPortal app, which can also be used with this telescope. Once aligned on three stars, selecting a celestial object and pressing ‘Go-To’ causes the Cosmos 90GT to slew to it. If your alignment is very accurate then >

INTUITIVE APP CONTROL Connecting and using your smartphone or tablet to operate the Cosmos 90GT couldn’t be simpler. The Wi-Fi activates when you power up the mount; select the SkyQLink-xx network on your device. Download and open the free Cosmos Navigator app, then select ‘Connect and align’ to perform star alignment. Once done you can use the onscreen control buttons to move the telescope manually, or tap on an

skyatnightmagazine.com 2014

object and select the Go-To option to slew to it. Occasionally the Wi-Fi connection was reported lost, but once reconnected we were able to continue from where we were last viewing. You won’t need to realign unless the power goes off. Using the app’s compass feature, we were able to hold our tablet skywards to identify stars, then tap Go-To to slew straight to it. Overall it became second nature in operation. The app also has a red light function, so there’s no threat to your night vision

FIRST LIGHT DECEMBER 91

SINGLE ARM FORK MOUNT The single arm easily carries the telescope tube via a Vixen-style dovetail arrangement. It also contains the integrated Wi-Fi network, features an aux port for an optional NexStar handset and a power connector for a battery pack.

STARPOINTER FINDER The StarPointer red-dot finder features a variable brightness switch. It is particularly useful when performing the initial alignment routine to aim at your chosen stars, but is not required once the alignment process has succeeded.

TRIPOD The aluminium tripod is light, but able to carry the weight of the mount and telescope. It can be adjusted for height for a more comfortable viewing position, but we did notice that vibrations take several seconds to dampen down. The single arm mount was very easy to install on the tripod.

ACCESSORY TRAY This tray has slots for two 1.25-inch fit eyepieces, plus an additional section where you can place extra eyepieces and accessories. It also features a holder for a smartphone or small tablet, with a rubber finish for grip.

skyatnightmagazine.com 2014

92 FIRST LIGHT DECEMBER

FIRST light

SKY SAYS… Now add these: 1. Celestron Cosmos Navigator app 2. PowerTank 7ah 3. Omni 2x Barlow lens

> the chosen target does end up reasonably close to the centre of the 25mm eyepiece, which has a 1° field of view. Bear in mind that the view is the right way up, but left and right are swapped. A clever little feature is that you can’t select an object near to the zenith or directly above, preventing the telescope from catching on the tripod, and a warning pops up telling you as much. It’s a nice touch. We enjoyed good views of prominent open clusters, including the Pleiades in Taurus and the Double Cluster in Perseus. The lovely Ring Nebula in Lyra was small in the 25mm eyepiece, but a nice smoke ring in the 10mm. The Dumbbell Nebula in Vulpecula was a fine sight in both eyepieces; back in Taurus, the Crab Nebula was fainter but still viewable as a hazy patch. The Andromeda Galaxy, meanwhile, appeared as a glowing oval patch with a hint of the surrounding disc. Searching nearby, we could pick out its two companions, M32 and M110. We also enjoyed a good range of double stars. Colourful Albireo in Cygnus was a treat, especially in the 10mm eyepiece, and by adding a 2x Barlow lens of our own we were able to split the triple star Iota Cassiopeiae. Finally, we took a tour of the Moon’s terminator and were rewarded with enough detail to keep us happy for a long time indeed. We even managed to capture a picture of it with our iPhone adaptor. Celestron have done a good job in bringing a basic beginners’ telescope into the 21st Century. If you are keen on getting the most out of your tablet or smartphone, you’ll certainly enjoy using it to take a tour of the heavens. S

WWW.THESECRETSTUDIO.NET

VERDICT BUILD & DESIGN EASE OF USE FEATURES GO-TO/TRACKING ACCURACY OPTICS OVERALL

skyatnightmagazine.com 2014

+++++ +++++ +++++ +++++ +++++ +++++

OPTICS The 3-inch primary lens gave reasonable views of bright deep-sky objects with the supplied eyepieces. Stars were sharp across 80 per cent of the view with the 25mm eyepiece and wide double stars could be split using the supplied 10mm. We needed to add a 2x Barlow lens to split close doubles.




ǁǁǁ�ĚĂƌŬƐŬLJƚĞůĞƐĐŽƉĞŚŝƌĞ�ĐŽ�ƵŬ  �ŝŶĨŽΛĚĂƌŬƐŬLJƚĞůĞƐĐŽƉĞŚŝƌĞ�ĐŽ�ƵŬd�Ϭϳ��ϰϬϬϭ�ϭϱ

94

FIRST light Olivon 10x50

See an interactive 360° model of these binos at www.skyatnightmagazine.com/olivon10x50

QB binoculars An entry-level instrument particularly suited to young stargazers

WORDS: STEPHEN TONKIN

WWW.THESECRETSTUDIO.NET X 5

T

SKY SAYS…

he 10x50 has become a The central half VITAL STATS standard for handheld of the image was binoculars, offering a • Price £84.99 good compromise of very crisp, but • Aperture 50mm light-gathering, magnification and stars deteriorated • Optics Multicoated weight. Olivon’s 10x50 QBs are also noticeably beyond • Magnification 10x water-resistant, a quality that is • Prisms BAK4 this region highly desirable on a dewy night. These • Angular field of view binoculars are supplied with a soft and 90m at 1,000m slightly padded nylon case, a neck strap, liable to slip • Focusing Zeiss centre-focus individual lens caps, a microfibre cleaning inadvertently. The • Eye relief 16.5mm cloth and a generic instruction leaflet. They eyepiece bridge is firm • Interpupillary distance have a 10-year guarantee. and does not rock in normal 57-74mm The binoculars are encased in a slightly mattuse. The minimum interpupillary distance is 57mm, • Weight 850g finish rubber armour, which affords a confident and the small eyepieces make this attainable. • Supplier Optical grip without having to hold them too tight. When you hold them up to the light, each of the Hardware The hinge, focus wheel and right-eyepiece dioptre exit pupils appears perfectly round, but the exit • www. ring all move smoothly with enough uniform pupils of a pair of 10x50 binoculars should be 5mm opticalhardware.co.uk resistance, making them easy to adjust but not in diameter and these appeared to be smaller. On • Tel 01226 203275 investigation we discovered that – in common with most binoculars of this class – although the physical aperture is 50mm, the light path SMALL INTERPUPILLARY DISTANCE is internally stopped down, in this case to an Many people with smaller faces or close-set eyes often find it difficult to find suitable effective aperture of 39mm. The aim of this is binoculars: the fashion for wide-angle eyepieces means that the eyepiece to reduce most optical aberrations to produce barrels are also wider, leaving a smaller space between them. This means that in practice the specified minimum interpupillary distance crisper, if slightly less bright, images. can be either completely unattainable, or only possible with some discomfort. But with a diameter of only 38mm, the Olivon QB’s eyepiece barrels are unusually small for modern 10x50 binoculars, most of which have eyepieces at least 5mm wider. These narrow eyepieces make the specified minimum interpupillary distance of 57mm much more likely to be attainable without the eyecups uncomfortably squeezing the bridge of your nose. An optical effect of the narrower barrels is a smaller field of view, but this is a minimal inconvenience in binoculars that will mostly be used handheld because you will instinctively place any target object in the sharper centre of the field anyway. The combination of lightness and small interpupillary distance makes these binoculars particularly suitable for younger observers.

skyatnightmagazine.com 2014

Optical assessment Naturally, we put this to the test. After focusing the binoculars we found that the central half of the image was very crisp indeed, but stars deteriorated noticeably beyond this region, showing coma near the periphery. The images from each side did merge properly, showing that collimation was well within acceptable tolerances. Pincushion distortion, which manifests as straight lines at the edge of the field appearing to curve in towards the centre, was present but not obtrusive. The on-axis colour correction is very good and, even off-axis, the limb of the Moon showed only minimal chromatic aberration. The binoculars are specified as being multicoated, which usually means that the outer surfaces of the objective lenses and eyepieces are coated, but the prisms are not. However, this did >

FIRST LIGHT DECEMBER 95

WATER RESISTANCE Given that binoculars are used in conditions that are often dewy, some water resistance is an enormous advantage. It reduces the likelihood of the optics being affected by the internal misting that can result if moisture does get into your binoculars, with the accompanying long-term damage of algal or fungal growth.

TRIPOD ATTACHMENT

MULTICOATINGS The coating on the eyepieces and the objective lenses has none of the tell-tale blotching that indicates shoddy workmanship. It gives equal reflectivity over the whole surface of each lens, suggesting that it has been evenly applied. The lens surfaces only minimally reflect a bright white light, showing that the multicoating is effective.

Although these binoculars are light enough to be handheld, you will be able to see fainter objects and split closer double stars if you mount them. Open up the snap-on cover and you’ll see that the Olivon QB has a standard 0.25-inch Whitworth mounting bush for a tripod adaptor L bracket.

RECESSED OBJECTIVE LENSES The objective lenses are recessed 16mm into their barrels. This not only acts as a glare shield, but also offers some protection against damage and lowers the possibility that you will accidentally touch them. This should reduce the frequency with which you need to clean the lenses.

skyatnightmagazine.com 2014

96 FIRST LIGHT DECEMBER

FIRST light

SHARP OPTICS

WWW.THESECRETSTUDIO.NET

There are aperture masks inside the objective barrels that change the effective focal ratio from f/3.5 to f/4.5. This has the advantage of reducing optical aberrations, at the cost of some light gathering, resulting in a crisper image that is only minimally affected by chromatic aberration.

> not result in the ghost images that can occur with uncoated surfaces, indicating that stray light is well controlled. With the eyecups up, the 4.7° Arrow asterism in Sagitta just fitted into the field of view. This is less than the 5.15° that the stated field of view of ‘90m at 1,000m’ implies. We found that this was because the eyecups do not let your eye close enough to the lens to see all of the field of view. It was possible to get the full field with the eyecups folded down, when we also found that there was insufficient eye relief for the full field to be visible with spectacles: because the eye lenses are recessed 6mm into their barrels the specified 16.5mm eye-relief is not fully usable. The Pleiades were well placed for our first light with these binoculars. We counted 47 stars, which is acceptable for a suburban location. Albireo was also available and, with the binoculars mounted, we were just able to split its two components, which are 34 arcseconds apart. The Perseus Double Cluster showed two distinct condensations of stars and the pose of the nearby Muscleman Cluster (Stock 2) was easily discernible. Kemble’s

skyatnightmagazine.com 2014

Cascade was indistinct, but definitely there, suggesting a limiting stellar magnitude somewhere between +8.5 and +9.0. The Andromeda Galaxy was a very easy spot, appearing as an elongated misty patch with a brighter middle. The often difficult Triangulum Galaxy was also visible high in the sky. Star colours were varied, with the brilliant white of Alderamin (Alpha (_) Cephei) contrasting beautifully with the vibrant orange-red of Herschel’s Garnet Star (Mu (+) Cephei), suggesting very good colour rendition. Overall, the combination of sharp optics, small size and lightness make this a good entry-level observing instrument for budding binocular astronomers. S

VERDICT BUILD & DESIGN EASE OF USE EYE RELIEF FEATURES OPTICS OVERALL

+++++ +++++ +++++ +++++ +++++ +++++

SKY SAYS… Now add these: 1. Standard TPA tripod adaptor 2. Visionary lander T830 tripod 3. Cleaning kit

98

FIRST light Starry Night Pro Plus 7

planetarium software A competent piece of software with plenty of bells and whistles

WORDS: PETE LAWRENCE

VITAL STATS • Price Physical copy $259.95; download version $249.95 • Updates Data and program available • Date range 99,999 BC to 99,999 AD • System requirements Windows 32- or 64-bit Vista or higher. Mac OSX 10.7 or higher. 1Ghz+ CPU, 1Gb+ RAM, 12Gb hard disk space, 128Mb OpenGL 1.4 graphics card, minimum 1024x768 display • Developer Simulation Curriculum Corp • www.starrynight.com • Tel 00 1 877 290 8256

P

lanetarium programs help Zoom into an area of sky and the SKY SAYS… us to make sense of the sky images are ‘streamed in’ as required. above on any given date, Amazingly, you can click on virtually The ability to from any location – even anything displayed and the program explore space is from the surfaces of distant worlds. will tell you about it – something impressive and Some are more sophisticated than possible thanks to an underlying star switching between database containing around 16 million others, allowing us to explore the textures and data entries and a deep-sky database listing bodies of the Solar System up close and even head out to look at other millions of objects. The interface has sets is amazing stars with planets. been restyled in Pro Plus 7, so it is now Starry Night Pro Plus 7 is the latest incarnation far less cluttered than previous versions. It’s a good in a long line of Starry Night planetarium idea to take a moment to get familiar with its programs and one that offers a bewildering array of operation via the excellent electronic user guide. bells and whistles. There are quite a few programs and apps around that can chart the sky. Some present the stars and constellations like you’d see One of the strengths of Starry Night Pro Plus 7 lies on a paper chart. Others, such as this one, display in how it allows you to explore the Universe. For the sky in a more realistic way, with lighting effects example, you can take a virtual trip to a significant that makes it feel as if you’re looking out of a number of the displayed stars, as well as visit those window rather than at a computer screen. with known exoplanets. The Solar System is That’s because this version of Starry Night uses rendered with proper sizes and orbits. The highly real CCD colour images for the background sky detailed textures for the planets and major moons display, showing stars down to magnitude +15.0. are a delight to view and explore, and we were >

Armchair exploring

PETE LAWRENCE X 6, THINKSTOCK

SEARCH LIKE GOOGLE With so much on offer, it’s difficult to pick out one feature that stands out above all the rest. However, we were particularly impressed by the universal search panel. This allows you to search for objects, features or program controls. When a control pops up in the results list it’s live, meaning you can alter its value from there. This helps to alleviate the problem a feature-rich program like Starry Night Pro Plus 7 has in respect of keeping its interface uncluttered and simple. Although a lot of the features can be accessed from drop-down menus, after a while we found ourselves using the universal search like you’d use Google to find something on the internet. For instance, typing ‘Telescope’ into the search box returned results including the constellation of Telescopium (the Telescope) as well as a list of pre-defined telescope types. Expand the telescope type list and you can, for example, add a field of view indicator for an f/9, 4-inch refractor fitted with a 25mm Plössl eyepiece to the main sky display.

skyatnightmagazine.com 2014

Universal search quickly becomes more intuitive than the drop-down menu system

FIRST LIGHT DECEMBER 99

MULTIPLE DATA SETS It’s possible to augment the star background image with other data sets – for example, to reveal filaments of galactic dust imaged in the far infrared. Some moons and planets also have this option. Examples include viewing the hydrocarbon lakes on Titan and the cometary impacts of Shoemaker-Levy 9 in Jupiter’s atmosphere.

TELESCOPE SUPPORT

INTERFACE The interface is very clean considering the range of functions on offer. The 146-page user guide is useful for learning the basics of how to operate the program, but most of the functions are fairly intuitive. Dates and times can be conveniently adjusted by highlighting them and using up/down cursor keys to change the values.

You can also use this software to control a telescope mount. The popular ASCOM interface is supported. Once connected, right-clicking an object brings up a menu which offers a ‘Slew to’ option. Starry Night Pro Plus 7 can also interface with MaxIm DL (not included). The telescope control panel provides an ‘Acquire image’ button for this purpose.

skyatnightmagazine.com 2014

100 FIRST LIGHT DECEMBER

FIRST light > impressed by the way that display data could be toggled. For example, while viewing the Galilean moon Io up close, it’s possible to swap to a geological feature map to help make sense of its complex surface. Other notable features include a huge 200,000 entry database of galaxies which can be viewed, rotated and zoomed, all in glorious 3D. Many exploratory spacecraft are also included, rendered as intricate 3D models, and it is great fun hitching a ride alongside during a mission highlight.

Flaws in design However, during our tests we found numerous data anomalies and some annoying design flaws. The object information window is too narrow for some of the content and it can’t be widened, while the help for some of the alternative data sets showed truncated text with no way of scrolling the hidden portion into view. The first time we searched for ‘Moon’ in the sky, the program took us to Taurus, which was unfortunate because at the search time the Moon was actually in Sagittarius. A similar hunt for M33 pointed to a mag. +15.0 galaxy in Hercules. To be fair, the real M33, a 7th-magnitude galaxy in Triangulum, was also listed in the search results. We also had several issues with the main display. We managed to make objects disappear from view; closing and re-opening the program restored them. Zooming into small patches of sky wasn’t always snappy; it took from a few seconds to over a minute for the background CCD sky panels to load. This was on a moderately fast PC (i7 core, Windows experience index 5.9) fitted with 16Gb of RAM. We’d sum up Starry Night Pro Plus 7 as being nearly there. Its ability to let you go out and explore space is very impressive and switching between textures and data sets is amazing. However, the current version has faults. Data anomalies coupled with silly design flaws and display bugs undermines its credibility. Serious practical observers have other alternatives, several of which are free. Whether the excellent extras are enough to tempt them to Starry Night Pro Plus 7 is questionable. S

PETE LAWRENCE X 2, THINKSTOCK

VERDICT ACCURACY EASE OF USE FEATURES FUNCTIONALITY REALISM OVERALL

skyatnightmagazine.com 2014

+++++ +++++ +++++ +++++ +++++ +++++

ALL-SKY IMAGES The all-sky background is based on real CCD images going as deep as magnitude +15.0. The images are dropped in as you zoom and pan around, and this can feel a little sluggish at times. It’s possible to turn the CCD images off and return to a fully computer-generated sky.

OBSERVING TOOLS There are various observational tools available, including observing highlights, an events list for the current planetarium date and an excellent ephemeris generator. The program also has superb chart printing capabilities – including the option to print three charts on one page, each covering a specified area of sky to reflect different equipment, such as binoculars, a finderscope and a telescope.

SKY SAYS… Now add these: 1. Suitable spec Windows or OSX laptop 2. Ascom drivers 3. MaxIm DL imaging software

Japan

Space Eye 70M A Great Xmas Gift! Price £129 The Vixen Space Eye 70M is the perfect starter scope package for beginner astronomers. Supplied with two Plössl eyepieces (10mm and 20mm) and 90˚ star diagonal, the scope will deliver excellent views of the planets and moon. A 5x20mm finderscope makes targeting quick and simple. “My overall impression is this telescope provides good value and should keep the beginner happy. It’s well made, easy and quick to set up”. David Powell, OBE - Secretary, Cardiff Astronomical Society

Oregon Observation Binoculars Available as 11x70 or 15x70 for just £99 Oregon Observation binoculars are excellent value for money for the first time or occasional user looking for a pair of large objective lens binoculars for long range terrestrial observation and star gazing.

To buy Vixen or Opticron star gazing equipment, please contact your nearest stockist: Vixen Stockists Bristol Bristol Cameras 0117 9140089 Devon First Light Optics, Exeter 01392 826133 Hertfordshire Tring Astronomy Centre, 01442 822997 London The Widescreen Centre, W1 020 7935 2580 West Sussex Astronomia, Rusper 01306 640714 West Yorkshire Green Witch, Leeds 01924 477719 For more information about Vixen and Opticron astronomy products please call 01582 726522 quoting reference SN12. Distributed in the UK by Opticron, Unit 21, Titan Court, Laporte Way, Luton, LU4 8EF

102

Books New astronomy and space titles reviewed

Galaxy: Mapping the Cosmos

THINKSTOCK

James Geach Reaktion Books £20 z HB

BOOK OF

TH E MO N T H

After recently enjoying a dark sky filled with seemingly countless stars on a clear autumn night, the opening paragraphs of James Geach’s lovely new book provided me with a sobering reminder that almost technological challenges of studying distant every object we can see with the naked galaxies, and what a century or more of eye lies, relatively speaking, on our cosmic observation has taught us about their doorstep in the Milky Way. And while overall properties considered en masse. The our massive spiral star system is hugely third chapter investigates the composition, important to us Earth-dwellers, it’s a mere grain of sand in the grand scheme of things. structure and classification of individual galaxies in more detail, while the fourth Galaxy: Mapping the Cosmos is a explores the complex story of beautifully illustrated exploration how they evolve from one of the Universe beyond type to another. Finally, the Milky Way, and the Geach looks at largemysteries and wonders scale models of early of extragalactic galaxy formation, astronomy. Geach unanswered is ideally placed to questions and be our guide on future challenges this journey – a for extragalactic researcher in the fastastronomy. For changing field of galaxy instance, most of evolution, he displays us have heard of dark both breadth and depth of matter, but how many of us knowledge, happily matched have come across the ‘missing by a talent for engaging, nonSpiral galaxy NGC 5584 resembles our baryons problem’? All in all, the technical prose and an eye for own Milky Way book is an enthralling, detailed a simile. His work with some and beautiful look at one of the most of the biggest and most advanced of challenging and exciting areas of modern modern telescopes also provides the astronomy, and a great addition to any vicarious pleasure of some armchair enthusiast’s library. astronomical tourism. The book is divided into five broad HHHHH chapters, each accompanied by lavish images from a wide range of telescopes GILES SPARROW is a science writer and a both on Earth and in orbit. After a broad Fellow of the Royal Astronomical Society introduction to our own Galaxy and the scope of the extragalactic Universe, Geach Reader price £17.99, subscriber price £16.99 looks in more detail at the scientific and P&P £1.99 Code: S1214/4 (until 26/01/15) skyatnightmagazine.com 2014

RATINGS HHHHH Outstanding HHHHH Good HHHHH Average HHHHH Poor HHHHH Avoid You can order these books from our shop by calling 01803 865913

TWO MINUTES WITH JAMES GEACH What inspired you to write this book? As a research astronomer, it’s easy to become complacent about the remarkable scale of the Universe. But one of the very first things I learned was that the cosmos was far bigger than I imagined, and I wanted to communicate that sense of scale. I also wanted readers to understand that our description of how galaxies work is still incomplete: there remains much we don’t know. Why is it important to study galaxies? Fundamentally, we want to understand the nature of our cosmic home – the Milky Way. We are embedded in a disc of stars and gas and dust, which is like an island in a great sea. When we look out into the sky we see billions of other islands, some of which are like ours. The drive to figure out where galaxies came from and how they work harks back to our most basic human instincts to explore and understand our world. How has galaxy research changed over the last 100 years? Just a century ago, debate was still raging as to whether there were other, ‘external’ galaxies to our own. Today, were are at the ‘final frontier’ where astronomers are gearing up to detect the signature when the stars in the first galaxies turned on. All the time, our model for how galaxies work has been refined. We have a pretty good idea of how galaxies have formed and evolved over time, but there is still a tremendous amount of work to do in this field. JAMES GEACH is a research fellow at the University of Hertfordshire’s Centre for Astrophysics Research

BOOKS DECEMBER 103

Zoom Bob Berman Oneworld Publications £8.99 z PB Zoom is an absolutely fascinating book about how everything moves – from galaxies to planets, insects and molecules. Even a cursory peek at the index at the back will give you a sense of the sheer range of the book’s discussions, which must have necessitated a great deal of thoughtful research on Berman’s part. Berman is an astronomy writer who was a columnist for Discover magazine for many years, and it occurred to him during a violent storm in New York state that he should expand his lifelong interest in the motion of celestial objects. So he decided to raid his savings and travel the world to find out about anything that moves – what are the fastest and slowest things in the Universe and everyday life? His account of what he discovered makes for an excellent read. Berman

Moon: Nature and Culture Edgar Williams Reaktion Books £14.95 z PB Moon: Nature and Culture begins by examining the various theories that seek to explain the origins of the Moon, as well as outlining the Moon’s physical evolution during the intervening four billion years or so. The Moon is the brightest object in the sky, second only in prominence to the Sun. It has been our constant companion, and since mankind first gazed up at it we have been under its spell, worshipping it as a god and even believing it to cause madness. As Williams reveals, the Moon has influenced our culture throughout the ages, figuring heavily in poetry and literature, art and cinema, mythology and folklore, politics and religion. Its regular cycle of phases provided us with a means of

covers everything from the expansion of the Universe to blizzards, bees, digestion, lighting strikes, meteors, gravity and sneezing. While this clearly means this is not strictly an ‘astronomy book’, he does explore many astronomical topics, including the size and shape of the Universe, ancient Greek philosophy about nature, and dark matter – the invisible substance that makes up most of the matter in the Universe, even if we can’t see it. The book is passionate, packed with interesting facts and numbers, and full of colourful details about the personalities responsible for key discoveries. It’s rich in imaginative turns of phrase and its chatty, anecdotal style is reminiscent of Carl Sagan’s Cosmos. The only real niggle is an editorial one: the book has relentless badly hyphenated line breaks, which are distracting for the reader. All in all though, it’s a delightful book, and quite obviously a labour of love.

HHHHH HAZEL MUIR is a freelance science writer Reader price £8.50, subscriber price £7.99 P&P £1.99 Code: S1214/2 (until 26/01/15)

measuring time, and even today determines when religious festivals such as Easter and Ramadan take place each year. In addition to its cultural influences, scientists and astronomers have continually examined the Moon as an astronomical object, and its practical significance to mankind is increasing. The present day upsurge in interest is covered in the book. A large number of probes are currently being sent to examine the Moon at close quarters, in preparation for a manned return for the first time since the last Apollo mission in 1972, and for the use of lunar resources. Moon: Nature and Culture is well illustrated throughout and, although the book does contain the occasional factual inaccuracy, this should not detract from its appeal as an enlightening and interesting account of the Moon and its continuing and expanding influence on mankind.

HHHHH BRIAN JONES is the author of 15 books on astronomy and space topics

Night Sky Watcher Raman Prinja QED £7.99 z PB It’s not often you have to unzip a book, but that’s exactly what you have to do to open the waterproof cover of Night Sky Watcher. This unusual format should prove handy on dew-drenched winter nights. Once inside, the book provides a basic introduction to observing the night sky. It uses clear language suitable for children, very colourful imagery, and does not assume the reader has any prior knowledge or equipment. The author begins by discussing the very basics of astronomy – what the lights in the sky are, why they appear to change over time and how best to set about observing them. Once you’re comfortable with that it moves on to the brighter constellations (including a couple of southern hemisphere examples), the planets and the Moon. It finishes with the author addressing the more unusual yet spectacular sights, such as comets, meteor showers and the aurora. The pictures and layout of the book are colourful, bold and, as promised, easy to read under the light of even a dim, red torch. The short chunks of text mean that it isn’t designed to be read cover-to-cover, but as a reference while observing, with instructions for navigating around the constellations accompanied by a smattering of ‘astrofacts’. Covering only a dozen or so constellations and relatively few binocular or telescopic targets, Night Sky Watcher really is for young beginners. This book will be a very useful guide in helping yours to find out where to start.

+++++ CHRIS NORTH is a presenter of The Sky at Night and a Herschel outreach officer Reader price £7.50, subscriber price £6.99 P&P £1.99 Code: S1214/3 (until 26/01/15)

Reader price £12.50, subscriber price £12 P&P £1.99 Code: S1214/1 (until 26/01/15)

skyatnightmagazine.com 2014

104 GEAR DECEMBER

Gear

Elizabeth Pearson rounds up the latest astronomical accessories

1

4 1 Joby Gorillapod SLR Zoom Tripod and Ball Head Price £64.95 • Supplier Wex Photographic 01603 486413 • www.wexphotographic.com This ultra-portable tripod can support up to 3kg. The innovative leg design lets the tripod adjust to any terrain and can attach to trees and railings, giving you a stable base for your astrophotos in even the most rural locations.

2 Celestron Lens Shade For C6 and C8 Tubes Price From £27 • Supplier Tring Astro 01442 822997 • www.tringastro.co.uk Protect your Schmidt-Cassegrain from dew and stray light with this dew shield. It is sewn rather than glued together for extra robustness.

2

5

3 Explore Scientific HR Coma Corrector Price À299 • Supplier Explore Scientific +49 2872 8074 400 • www.explorescientific.co.uk Eliminate coma, field curvature and astigmatism from your Newtonian telescopes with an HR coma corrector. It works for very fast systems, down to f/3, and delivers high-resolution visual observations.

4 Baader Eudiascopic ED 35mm Price £155 • Supplier Astronomia 01306 640714 • www.astronomia.co.uk With generous eye-relief on all focal lengths, this eyepiece offers superior sharpness and colour correction across the entire field, and has a tough, scratch-resistant multicoating.

3

5 Lagoon Nebula Scarf

Price £30 • Supplier Royal Museums Greenwich 020 8312 6700 • http://shop.rmg.co.uk The beautiful Lagoon Nebula, as captured by the 0.5m Siding Spring Observatory, is shown on this lovely silk-cotton mix scarf.

6 Indicating Silica Gel Packets

Price £18.70 for 10 • Supplier Silica Gel Packets +1 843 564 6135 • www.silicagelpackets.co.uk Protect your optics from water damage by storing them with a silica gel packet. Orange balls within the 28g packet change colour when the silica can absorb no more moisture.

skyatnightmagazine.com 2014

6

106 EXPERT INTERVIEW DECEMBER

WHAT I REALLY WANT TO KNOW IS…

Is it still hot inside the Moon? Sander Goossens is using satellite data to look deep below the lunar surface and investigate its syrupy centre INTERVIEWED BY PAUL SUTHERLAND

T

he Moon used to be thought of as a cold, dead world, but with NASA’s Apollo programme we got tantalising hints that this assumption did not reflect reality. The astronauts on those missions left mirrors on the lunar surface, which scientists on Earth bounced lasers off to precisely measure the distance, plus seismometers to record moonquakes. And although the data from these experiments was not very well distributed, because the spacecraft only landed in a few areas around the lunar equator, it quickly became clear that the Moon had some structure – that it wasn’t simply hard rock all the way through. The suggestion was that there might be a core to the Moon, and then a softer, hot layer between that and the base of the rocky mantle. The Moon wobbles a bit as it rotates on its orbit around the Earth, an effect called libration. The laser measurements that the Apollo mission made possible have gauged this effect precisely, giving scientists a great deal of information about the Moon’s rotation. This showed that there was something within the Moon other than just solid rock. It’s a bit like spinning a hard-boiled egg and a raw egg: a boiled egg spins neatly and uniformly, while a raw egg has a different sort of wobble and motion because of the liquid inside it.

The results show us what it is like deep beneath the lunar surface. They confirmed that the Moon does indeed have a core. We expect that the core itself will be partly liquid, with a part-solid inner core, but we do not yet fully understand its form. Around the core, and very deep beneath the mantle, is a hot layer which is very much softer in terms of its viscosity – like a syrup of partly molten stone – which controls the way the Moon rotates. We simulated this layer for various thicknesses, taking into account what scientists have discovered using seismology, and our results suggest it is about 150km deep. Above that, the results tell us, is solid rock.

Core issues

Once assumed to be just a chunk of rock, the Moon is now thought to have a semi-liquid core

© STOCKTREK IMAGES/INC/ALAMY

Getting under the skin Both the seismology experiments and the laser test showed that the Moon’s behaviour could not be explained by the then current models of its interior. We were able to examine this more closely using data sent back in recent years from Japan’s SELENE mission and China’s Chang’e-1 mission, which both orbited the Moon. We started testing various models of the interior of the Moon to find out which of them best matched the results from those probes and the Apollo experiments. skyatnightmagazine.com 2014

ABOUT SANDER GOOSSENS

Dr Sander Goossens is an assistant research scientist at NASA Goddard Space Flight Center’s Planetary Geodynamics Laboratory, where his work involves trying to get under the skin of Earth’s closest neighbour.

Now, it is all very well to be able to find this explanation for the measurements that were made, but if you invoke this soft layer around the core, then you also have to explain how it can maintain its hot, soft nature over lunar history. You might imagine that the lunar interior would have solidified eventually, because there was not enough heat to keep it partly molten – and that is indeed one of the big issues. But we now think the situation is similar to what occurs with Jupiter’s innermost main moon Io, where it is driven by tidal forces and is kept liquid inside because of the gas giant’s powerful gravitational pull. A similar mechanism seems to be working with our Moon, which would solidify inside were it not for the pull of the Earth. These tidal forces keep this layer in a state of constant friction, so that it remains partly liquid. We are now working to improve our model using data from a pair of NASA probes called GRAIL, which orbited the Moon during 2012 to produce a very detailed map of its gravitational field before being crashed onto the surface. That should help us get a better understanding of what lies beneath the lunar surface. S

The Southern Hemisphere in December With Glenn Dawes

WHEN TO USE THIS CHART The chart accurately matches the sky on the dates and times shown. The sky is different at other times as stars crossing it set four minutes earlier each night. We’ve drawn the chart for latitude –35° south.

RT O N

H E AS T

1 DEC AT 00:00 UT 15 DEC AT 23:00 UT 31 DEC AT 22:00 UT

r

as to

x

llu

Po

`

CAN

INI

CER a

M44

X

10

b

th

ter

N O R

`

_

n

b

cyo

pi

Despite the southern hemisphere’s brilliant views of the Milky Way, there is a short section of our Galaxy too far north to be visible from mid-latitude Australia. The summer northern extreme is marked by Perseus, the rescuer of Andromeda. Sitting on the northern evening horizon, Perseus is shaped like the Greek letter Nu (i). The best marker to finding it is mag. +0.1 star Capella, the alpha star in Auriga. This charioteer is best recognised by its pentagon of stars, of which Capella is by far the brightest.

Ju

STARS AND CONSTELLATIONS

The four Galilean moons shuffle back and forth across Jupiter’s disc, showing transits and occultations. On the morning of the 11th, the eastern states of Australia will see Ganymede pass into Jupiter’s shadow at 01:24 EST; watching this 5th-magnitude body fade and disappear over a few minutes is fascinating. At that time three moons are visible on the western side, Ganymede being the closest to Jupiter. Western Australia sees a similar event on 18th at 03:22 WST, with Ganymede the closer of two on the west side.

LEO

DECEMBER HIGHLIGHTS

M

THE PLANETS

C

Alphard

HY

_

A

DR ost

Gh

closest approach next month. Jupiter arrives around 23:00 EST mid-month, best viewed in the northeast morning sky. Saturn returns to the morning; in the latter half of the month it will be low in the dawn sky not far from mag. +1.1 Antares (Alpha (_) Scorpii).

EAST

The early evening sky belongs to Mars, low in the west as twilight ends. The second half of December sees brilliant Venus return to the evening twilight, to the lower left of the Red Planet. Mercury gradually rises out of the glare below Venus, with

MONO

o er

3 arcminutes away. Another 7° west sits the double of mag. +3.6 Theta (e) Ceti.

ROBERTO MURA

A

VEL

skyatnightmagazine.com 2014

TLIA

`

ASTEROID TRACK

DOUBLE STAR

METEOR RADIANT

VARIABLE STAR

QUASAR

MAG. +3

COMET TRACK

PLANET

MAG. +4 & FAINTER

MAG. 0 & BRIGHTER MAG. +1 MAG. +2

S EA

PLANETARY NEBULA

STAR BRIGHTNESS:

DIFFUSE NEBULOSITY

OPEN CLUSTER GLOBULAR CLUSTER

net Blue Pla b

H UT SO

CHART KEY GALAXY

_

`

Cetus is also home to a multitude of galaxies, most very faint. NGC 720 (RA 01h 53.0m, dec. –13° 44’; pictured) is an exception. This mag. +10.1 elliptical galaxy is located 3.4° south of Zeta (c) Ceti. It is distinctively oval in shape, approximately 1x2 arcminutes, with an impressive star-like nucleus.

AN

_ TER CRA

The faint constellation of Cetus in the northern evening sky has numerous binocular double stars. A fine example is mag. +3.7 Zeta (c) Ceti (RA 01h 51.4m, dec. –10° 20’) and mag. +4.6 Chi (r) Ceti, respectively yellow and white stars that are separated by 0.6°. Although considered naked eye, binoculars will help to show their colour. Chi itself is an easy double with a mag. + 6.8 companion

PY

f Ju pit

DEEP-SKY OBJECTS

T

SOUTHERN HEMISPHERE NORTH California Nebula

`

N

b 3 M3

M3

6 M3

7

U NG A RI

` M35

_

T

_

`

AURIGA

`

R

`

4 M3

NG

M LU a b

O

AN DR

7

C

A

ED

l go

`

l

US

re ua Sq s t a u e Gr egas P of

31s t E

r

ba

lde

A

7th

_ ON

ORI

nka

PI

SC

PE

ES

clip tic

GE

an

r

G

a

AR

des

4t h Hy a a d e TAURU s S Vb

b

IES

AS

Pleia

Hama

Celes tial

tor

Equa

Cir

CETUS

`

a

_ b

`

a

`

1

`

ox

_ `

_

CIRCINUS

`

Rige

US

l Ken

t

a

`

os ait bK ne De

_

0 30 C NG

_

S

`

b

`

_

a

PISCIS AUSTRINUS

a

US b GR

`

a

b INDUS

_

b

`

M TRIANGULU AUSTRALE _

b

`

a

Fomalhaut

R b _

PTO CUL

X a

`

b

A

a

NS

` _

_

S

NA RO RA O C ST

b

b

a

ENI PHO

r na her Ac

62 C3 NG

`

a b APUS

N CA TU

ES T

_

A

`

UT HW

b

SC

RU S

OCTA

b

el B

CENTAUR

South Celestial Pole

`

C

tune

Nep

O

_

Coal Sack Jew

es

MU

b SM

a HY D

PA VO

a

ru x

A

MENS

b

Ple iad

_

` b a X CRU

Pr

a

Ac

a

nae

ern

_ 6

`

Tuca

a

So uth

_

47

`

S

Gem Cluster

`

` 14 6

`

G C

R

c

N

S

IU

bula

b

N CHAMAELEO

VOLAN S _

_

b a

AQ

R UA

Helix Ne

a _

¡ _

`

ebula Tarantula N b LM ` C R

3

_

25

DO

OR

PICT

CAR INA

b

_

ULUM

RA

s

a

IUM

a

RETIC

_

DO

`

RO LO G

NG C

A

HO

_ _

UM

MB

a

b

`

`

a

pu no Ca

IS

YX

`

a EL CA

IS

_

WEST

`

`

a

_ M4

b

PUPP

b CO LU

bula tary Ne

cle

a

M78 M43

b el

s

R

MAJO

7

M4

LEPUS

_

a

b

t

28

Mira

b

` Rig

2

th

_

Uran us

b

b

1s t

W

_

Alr

esc

a

ha

Me

_ a M4

Siriu

a CANIS

_

CEROS

US ERIDAN

a

0

`

M5 le

a

p

Al

b ng

M

52

_

ette Ros ula b Ne

_

M48

rT ria

O

EUS

PERS

Ca

Betelgeuse

a

`

M

te

ES T

pe lla

b

b

CA a N IS in

RT HW

Almach

_

_ W

A

AR

SOUTH

skyatnightmagazine.com 2014

ADVERTISEMENT FEATURE

UK

Retailer Guide Find the right one for you: buy your telescope from a specialist retailer

I

t is quite easy to become daunted by the vast array of equipment that is available to today’s amateur astronomers. Different makes, different models, different sizes and optical arrangements – if you’re new to the hobby, how do you make sense of all these details and find the telescope that will show you the Universe? The answer lies in buying from a specialist retailer – somewhere that really knows what they’re talking about. Like the retailers in this guide, they’ll have the practical knowledge that will guide you towards the scope that won’t end up gathering dust in a cupboard. Today there are over 1,000 models of telescope to choose from – refractors and reflectors, Dobsonians and Newtonians, Schmidt- and Maksutov-Cassegrains. And just as important as the telescope is the mount it sits on; but do you go for equatorial or altazimuth, manual or Go-To? And what about accessories like eyepieces and finderscopes? That’s certainly a lot to consider before making a decision, but a specialist retailer will help you make that decision, taking important considerations like portability, construction and price into account. So if you need friendly, face-to-face advice and excellent aftersales service, free from biased opinions, specialist telescope retailers are the place to go for a helping hand through the technical literature and tables of figures. They’ll help you find a scope that combines quality and convenience at a price that’s right.

ADVERTISEMENT FEATURE

TELESCOPE HOUSE Founded in 1785, Telescope House has been responsible for supplying many well-known Astronomers with telescopes and equipment. The late Sir Patrick Moore bought the majority of his telescopes from the company, including his very first instrument. With a friendly showroom in Surrey, a number one ranked retail website and a service centre with fully qualified staff, the company offers equipment from manufacturers such as Meade, Revelation, Coronado, Bresser, Skywatcher, Orion USA, TeleVue, Vixen and Explore Scientific. Whether it’s advice on your first telescope, to setting up advanced Astrophotography systems, the staff at Telescope House have a wealth of experience and instant access to the right stock to back it up.

01342 837610 www.telescopehouse.com [email protected]

SHERWOODS Established for over 60 years, we at Sherwoods are one of the Midlands leading suppliers of astronomical telescopes, binoculars and accessories. Through our website and showroom we are able to supply optics from some of the world’s leading optical manufacturers including Celestron, Skywatcher and Meade at some of the lowest prices in the UK. We offer a full mail-order service including next day delivery on many items held in stock.

TRING ASTRONOMY CENTRE At Tring Astronomy Centre we know that choosing the right equipment can be a minefield, but we strongly believe that seeing telescopes in the flesh and talking to an expert in a relaxed environment can really help. That’s why we have a coffee machine, a fully stocked bicuit barrel, and 45+ telescopes on display. As well as representing leading brands such as Celestron, Sky-Watcher, Baader Planetarium, Altair Astro, Vixen, Opticron, AstroTrac, iOptron, Lunt, Starlight Instruments, ZW Optical and many more we also offer a hire service so you can even try before you buy! So what are you waiting for? Visit or contact Tring Astronomy Centre and lets talk Astronomy!

01442 822997 www.tringastro.co.uk [email protected]

THE WIDESCREEN CENTRE The Widescreen Centre is London’s Astronomy Showroom, located in Sherlock Holmes territory off Baker Street in the heart of Marylebone - a family owned and run business since starting out in1971. Our experienced and highly knowledgeable staff will offer you quality, choice, expertise and service - see Celestron, Sky-Watcher, Meade, Orion, Tele Vue, APM, Takahashi and much, much more besides says Simon Bennett, Widescreen’s MD and lifelong amateur astronomer, “If the correct equipment is purchased it will give a lifetime’s enjoyment. This is our mission. We will never sell you anything you don’t need” Watch out for Widescreen at Star Parties and exhibitions throughout the UK.

01527 857500 www.binocularhouse.com [email protected]

02079 352580 www.widescreen-centre.co.uk [email protected]

GREEN WITCH

ASTRONOMIA

Green Witch is one of the UK’s leading suppliers of telescopes, binoculars and accessories for astronomy. Founded by former members of the Royal Greenwich Observatory in 1998, Green Witch is dedicated to helping you choose and use the equipment that is right for you. We also carry an extensive range of telescopes and binoculars for nature and leisure, which you are welcome to try before you buy. Whether you visit our showrooms or buy online you can be sure of excellent service.

Atronomia is the award-winning home of the biggest range of telescopes and binoculars on display in the South of England. With over 50 telescopes and even more binoculars, Astronomia brings you the widest choice from respected brands such as Celestron, Sky-Watcher, Meade, Vixen and more. Visit our store in the High Street, Dorking or check out the website. Take advantage of our fullprice trade-ins on all telescopes – if you upgrade within 12 months, you don’t lose a penny!

01924 477719 - Birstall, West Yorks 01767 677025 - Gransden, Beds & Cambs www.green-witch.com

01306 640714 www.astronomia.co.uk [email protected]