BBC Sky at Night 2013-06

THE GREATEST ADVANCES IN ASTROPHOTOGRAPHY

Sky at Night THE BIGGEST NAME IN ASTRONOMY

A DECADE

OF DISCOVERY Mars Express celebrates 10 years at the Red Planet PLUS

Explore the lunar domes

Observe and image the Moon’s extinct volcanoes

Deep-sky databases

The best catalogues for finding faint fuzzies

Dark moon The black rain that fell on Jupiter’s satellites

ALSO IN THIS ISSUE ON TEST: Orion’s 16inch Go-To Dobsonian telescope

See the Sun safely with a solar funnel The woman who found the Horsehead Nebula On location at the unveiling of ALMA JUNE 2013 #97 www.skyatnightmagazine.com

LETTER FROM THE EDITOR JUNE 03

Welcome

This month’s contributors include... EMILY WINTERBURN

The art of astrophotography has come a long, long way

ASTRONOMY HISTORIAN

T

en years ago this month a rocket launched for Mars, carrying a spacecraft that was to dramatically improve our view MARK PARRISH of the Red Planet. AMATEUR SCOPE MAKER Mars Express studied In this month’s the ice caps at the poles, mapped the Martian How to surface to an unprecedented degree and on page much more. Turn to page 38 to learn how 82, Mark the mission defied all expectations and see explains how easy it is to some of its most significant images. make a solar funnel to These digital images are a sharp contrast to project the Sun safely. the way the Horsehead Nebula was discovered KEV LOCHUN – on a photographic plate by a pair of human PRODUCTION EDITOR eyes. To mark the 125th anniversary of the Kev talks to Mars event, on page 74 we look at the story behind Express the woman those eyes belonged to, Mina scientist Fleming, and how she was one of the first to Olivier Witasse to find out what’s gain recognition in the male-dominated world of 19th century astronomy. next for the intrepid orbiter on page 38. There’s much more on the history of astrophotography on page 68, as we chart PAUL MONEY how we’ve advanced from black and white REVIEWS EDITOR Turn to page daguerreotypes of the Moon to smartphone 90 to find astro imaging, ahead of the opening of a major out what exhibition at the National Maritime Museum Paul thought called Visions of the Universe this month. of iOptron’s SkyTracker camera mount, Nowadays, of course, astronomers can study a light bit of kit for taking the cosmos using non-visual areas of the wide-field shots. spectrum; on page 62 Kieron Allen reports

From the first transit of Venus to anti-fraud dashcams, on page 68 Emily reveals the 25 defining moments in astrophotography.

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from the opening of the latest radio observatory, the Atacama Large Millimeter/ Submillimeter Array in Chile. I’m also pleased to tell you that Patrick Moore has been posthumously shortlisted in the Columnist of the Year category at the PPA Awards 2013. The winner will be announced on 19 June – we’ll keep you posted. Enjoy the issue! PAT R I C K M O O R E

Chris Bramley Editor

PS Next issue goes on sale 20 June.

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In the magazine ON THE COVER 38

68

NEW TO ASTRONOMY? See The guide on page 80 and our online glossary at www.skyatnightmagazine.com/dictionary

38

MARS EXPRESS: A DECADE OF DISCOVERY

74

THE HORSEHEAD NEBULA

82

33 80 16 94 74

98

FIRST LIGHT

62

FEATURES

REGULARS

06 Eye on the sky

11 Bulletin

The latest astronomy and space news.

82 How to

33 Explore the lunar domes

19 What’s on

Make a solar funnel.

The latest stunning space images.

How to spot these enigmatic volcanic features.

38 A decade of discovery

The science and success of the Mars Express mission, encapsulated by 10 of its most significant images.

62 To the ends of time with ALMA

How the world’s largest radio telescope could change our understanding of the Universe.

68 Great advances in astrophotography

The 25 developments that shaped astro imaging.

74 Unveiling the dark knight The story behind the discovery of the Horsehead Nebula, first identified 125 years ago this month. skyatnightmagazine.com 2013

80 Skills 80 The guide Deep-sky catalogues.

Astronomy events from around the UK.

85 Sketching

20 Sky at Night diary

86 Scope doctor

Asteroid 6 Hebe.

Your backstage pass to the TV show.

We solve your equipment woes.

22 Interactive

87 Lost in space

26 SUBSCRIBE

First light 90 iOptron SkyTracker camera mount. 94 Orion SkyQuest XX16g

Your letters, emails and tweets.

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28 Hotshots

The finest of your astro images.

47 THE SKY IN JUNE Your 15-page guide to the night sky featuring our pick of the top sights, an all-sky chart, a deep-sky tour and much more…

89 Reviews

Dobsonian telescope.

98 Mesu-Mount 200. 102 Books 104 Gear

106 What I really want to know is…

Can robots build us a base on Mars?

MAN IN SPACE iPAD APP

Celebrate 50 years of mankind’s adventure in space

The Man In Space app is more than a digital book – it’s a complete multimedia experience. Tap the screen to play videos, rotate spacecraft views and bring interactive elements into play. You’ll never feel closer to being in space. This app features:  3D views of legendary spacecraft, allowing you to examine them from different angles  Themed photo galleries featuring amazing images  Historic video footage  Interactive diagrams  360º panoramic views of the Moon  A foreword by Sir Patrick Moore

AVAILABLE NOW ON iTUNES – ONLY £3.99 To download visit www.skyatnightmagazine.com/man-in-space-ipad-app skyatnightmagazine.com 2012

EYE ON THE SKY JUNE 07

Blaze

glory of

Herschel reveals the inner workings of a stellar nursery and its fledgling massive stars

skyatnightmagazine.com 2013

UNIV. TORONTO, HOBYS KEY PROGRAMME (F. MOTTE)

Vast clouds of interstellar dust blaze a fiery hue in this three-colour image of the W3 giant molecular cloud, a colossal stellar nursery almost 200 lightyears across and located on the Milky Way’s distant Perseus Arm. One of the largest star-forming regions in the outer Milky Way, the mammoth cloud is host to stellar nurseries cultivating both low- and high-mass stars. The youngest regions in the scene are the dense, bright blue areas of hot dust at the top left of the image, which contain massive stars around eight times the mass of our Sun. This infrared view helps us understand how these massive stars are formed as well as the effect they have on the areas around them, in particular how the radiation produced during their early formation heats up gas and dust.

ESA/PACS & SPIRE CONSORTIA, A. RIVERA-INGRAHAM & P.G. MARTIN,

HERSCHEL SPACE TELESCOPE 27 MARCH 2013

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▲ Born in a brawl

This composite image, created using optical and X-ray observations, shows Kepler’s Supernova Remnant in exquisite detail. The red, green and blue colours allude to low-, intermediate- and high-energy X-rays captured by Chandra. A new analysis of its data has revealed that the Kepler supernova was triggered by an interaction between a white dwarf and a red giant star.

SCIENCE INSTITUTE, NASA/JPL-CALTECH, NASA/SDO, ESO

X-RAY: NASA/CXC/NCSU/M.BURKEY ET AL; OPTICAL: DSS, NASA/JPL-CALTECH/SPACE

CHANDRA X-RAY OBSERVATORY 18 MARCH 2013

 Resolving Rhea’s ruts CASSINI SPACECRAFT, 10 MARCH 2013 Taken from a distance of approximately 280,300km, this stunning Cassini image captures great detail on Rhea, Saturn’s second largest moon and the ninth largest in our Solar System. Rhea is a heavily cratered satellite made up of around seven per cent ice that bears many similarities to Saturn’s smaller moon Dione.

skyatnightmagazine.com 2013

EYE ON THE SKY JUNE 09

 On the rove again MARS SCIENCE LABORATORY, 25 MARCH 2013 NASA’s Curiosity rover snaps a self-portrait before preparing to resume full science operations after a short break. This followed a technical glitch with one of the rolling lab’s onboard computers. The image captures two of the rover’s six 50cm-diameter aluminum wheels, which have so far traversed more than 1km of Martian terrain.

▲ Earth’s fuzzy fringe SOLAR DYNAMICS OBSERVATORY 11 MARCH 2013 For a short time each day over about three weeks every year, NASA’s Solar Dynamics Observatory witnesses an eclipse as Earth’s shadow obscures the Sun. Unlike the clean lines seen when the Moon casts its shadow on the Earth, our planet’s shadow is fuzzy due to its opaque atmosphere.

 Stunning neighbour EUROPEAN SOUTHERN OBSERVATORY 20 MARCH 2013 ESO’s Very Large Telescope has captured the spiral galaxy NGC 1637 in unprecedented detail in this new image. The galaxy is relatively close to our own, located just 35 million lightyears from Earth in the constellation of Eridanus.

skyatnightmagazine.com 2013

BULLETIN JUNE 11

Bulletin The latest astronomy and space news written by Hazel Muir

PLUS

CUTTING EDGE

Our experts examine the hottest new astronomy research papers CHRIS LINTOTT LEWIS DARTNELL

14 16

Comment

by Chris Lintott

Stars are believed to push gas away, limiting their growth; close neighbours could prevent this

Is this the secret to massive star formation?

MARK GARLICK/SCIENCE PHOTO LIBRARY

The mightiest stars have a little bit of help from their friends it seems NEWBORN STARS MAY be able to grow to a massive size if they are surrounded by a gang of close neighbours, a new study suggests. The research from the University of Toronto in Canada may explain the mystery of why stars more than 10 times as massive as the Sun even exist – theory predicts that they shouldn’t form at all. As stars form from collapsing clouds of gas, they heat to the point that they begin to push the gas around them away. Astronomers expected this process would halt a star’s growth when it becomes about eight times as massive as the Sun. “Radiation during the birth of high-mass stars is so intense that it tends to destroy and push away the material from which they need to feed for further growth,” explains Alana RiveraIngraham, who led the study while she was

a graduate student at the University of Toronto. Her team discovered clues about how very massive stars form in observations of a cloud of gas and dust called Westerhout 3 (W3), which lies 6,500 lightyears away in the Milky Way’s Perseus Arm. The observations, made by ESA’s Herschel Space Observatory, suggest that small stars can grow very massive if they happen to be cocooned within groups of older stars that confine their younger siblings and ‘feed’ them with gas. In other words, when a newborn star starts to push its ‘food’ source away, nearby neighbours can nudge the gas straight back. “This observation may lift the veil on the formation of the most massive stars which remains, so far, poorly understood,” says Rivera-Ingraham. > See Comment, right

The real story here is that the formation of massive stars is complicated and that new observations like these are likely to make things worse before they get better. Let’s start with the good news. W3 is one of the best-studied complexes of massive forming stars, but we’ve never had a view of it like this one from the Herschel Space Observatory. The telescope’s ability to work in the far infrared catches the very early stages of star formation, and reveals filaments twisting their way between and around these protostars. Add this complexity to the fact that the youngest stars appear to live in the centre of the cluster and you have a picture that is compatible with the theory promoted by the authors. In truth things are so complicated that it’s hard to distinguish this model from many others and arguments will continue for years. This is just a first look at Herschel’s valuable data – there will be much more to come. CHRIS LINTOTT presents The Sky at Night on BBC TV

skyatnightmagazine.com 2013

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Spiral arms are great survivors The swirls of stars in many galaxies persist for billions of years

News in brief BLACK HOLE SMASHES ORBIT RECORD

NASA/ESA AND THE HUBBLE HERITAGE (STSCI/AURA)-ESA/HUBBLE COLLABORATION, THINKSTOCK X 2, NASA/JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY/CARNEGIE INSTITUTION OF WASHINGTON, ESO/L. CALÇADA/M.KORNMESSER, ESA/BONSOR ET AL

ESA’s XMM-Newton satellite has shown that a star and black hole discovered in 2010 are orbiting each other at record speed, once every 2.4 hours. That beats the previous record by almost an hour. The pair lie at an uncertain distance, but the black hole, illustrated below, is thought to be at least three times as massive as the Sun, while its companion is a red dwarf star. “The companion star revolves around the common centre of mass at a dizzying rate, almost 20 times faster than Earth orbits the Sun,” says Erik Kuulkers of ESA’s European Space Astronomy Centre in Spain.

The arms of spiral galaxies like M74, above, may not be the transient features astronomers first thought them to be

THE MAGNIFICENT SPIRAL arms of giant galaxies like the Milky Way can persist for surprisingly long periods of time, new computer simulations suggest. Astrophysicists say the simulations should clarify a mysterious aspect of galactic evolution. “We show for the first time that stellar spiral arms are not transient features, as claimed for several decades,” says team member Elena D’Onghia, from the University of Wisconsin, Madison. “They are self-perpetuating, persistent and surprisingly long-lived.” Our own Milky Way has several bright arms of dense stars that spiral out from a bar of stars at the galactic centre. And nearly 70 per cent of the galaxies closest to the Milky Way are also spirals, suggesting such galaxies are an extremely common upshot of galactic formation processes. But the evolution of spiral arms has been a long-standing puzzle. Why do they form and how do they change over time? Two theories have predominated. One is that spiral arms form and then disperse, so they’re quite short-lived. The other maintains that gravity makes material in spiral arms jam up and persist for long periods. skyatnightmagazine.com 2013

Now D’Onghia’s team has investigated this in powerful simulations of how gravity and other forces would sculpt as many as 100 million ‘stellar particles’ into familiar galactic shapes. The results suggest that spiral arms form due to the influence of dense molecular clouds in space and could potentially be sustained indefinitely – even when the forces that created the arms are removed. Once formed, spiral arms in a galaxy like the Milky Way should persist for at least eight galactic years according to this study, equivalent to the amount of time it would take the Sun to make eight orbits of the galaxy. That amounts to at least 1.8 billion years. “Once the arms are generated through these clouds, they can exist on their own through the influence of gravity,” says D’Onghia. “The arms self-perpetuate.” The team’s results also make predictions about how many spiral arms a galaxy should have depending on its structure, something that should be easy to test with telescope observations within the next few years. www.wisc.edu

MINI SUPERNOVAE REVEALED

An all-new kind of curiously faint supernova has been discovered. Supernovae were thought to occur in two main varieties – Type Ia, in which a white dwarf star blows apart, and Type II, in which a very massive star’s core violently collapses. Now Ryan Foley from the Harvard-Smithsonian Center for Astrophysics in Massachusetts has identified another type, dubbed Type Iax, which might be a white dwarf exploding but not destroying itself. “It’s the runt of the supernova litter,” says Foley.

BULLETIN JUNE 13

ODD ROCKS COULD BE FIRST FROM MERCURY News in brief GREENISH ROCKS DISCOVERED in Morocco in 2012 might be fragments of the first meteorite from Mercury ever found on Earth, a scientist has claimed. However, the suggestion is controversial because their ages don’t match Mercury’s surface. Analysis of one fragment by Tony Irving from the University of Washington in Seattle has revealed that the stone has very unusual chemistry. Its composition is curiously similar to that of Mercury’s surface, as measured by NASA’s Messenger probe. “It is high in magnesium and very low in iron,” comments Randy Korotev, a meteorite expert from Washington University in St Louis, Missouri. However, critics argue that the rock is 4.5 billion years old, significantly older than Mercury’s surface. “If it’s not from Mercury, then where is it from?” says Korotev. “That’s really the question.” www.washington.edu

MAGAZINE VISITS US READERS

The rocks match Mercury’s composition, but not its age

Sleeping giant becomes a raging beast

For the second year running, Sky at Night Magazine visited the biggest astronomy show in the US, the North East Astronomy Forum (NEAF), in the village of Suffern, New York, in April. Editor Chris Bramley and advertising manager Steve Grigg, pictured below, met some of the 4,000 visitors at the event, talking with US readers and exhibitors. “It was fantastic to catch up with people I met at the show last year and who subscribed for the first time, renewing their subscriptions again this year,” says Chris. Next year’s show takes place on 26-27 April.

A dormant black hole has been caught munching on an unwary traveller

NEW SUPERNOVA DISTANCE RECORD

The black hole is believed to have flared as it snacked on a passing star or planet

A DISTANT BLACK hole has awoken from a decadeslong nap to snack on a giant planet – or possibly a brown dwarf star – that ventured too close. Using ESA’s Integral satellite, a team led by Marek Nikolajuk from the University of Bialystok in Poland discovered a bright X-ray flare from galaxy NGC 4845, which lies about 47 million lightyears away, in 2011. “The observation was completely unexpected from a galaxy that has been quiet for at least 20 to 30 years,” says Nikolajuk.

Observations suggest the flare occurred because the galaxy’s central black hole ripped off the outer layers of a brown dwarf 14 to 30 times as massive as Jupiter. It’s also possible that the object was a smaller, gas giant planet. A similar event is due with the supermassive black hole at our Galaxy’s centre. It could swallow a smaller meal, a close gas cloud just a few times as massive as Earth; astronomers hope to observe our black hole enjoying this lighter bite within a year. http://sci.esa.int/integral

The Hubble Space Telescope has spotted the most distant supernova explosion ever seen. The blast was so far away that its light took more than 10 billion years to reach Earth, breaking previous records by about 350 million years. The explosion was a Type Ia supernova, linked to unstable white dwarfs. “These supernovae are important tools for studying the dark energy that is speeding up the expansion of space,” says Adam Riess from the Johns Hopkins University in Maryland.

skyatnightmagazine.com 2013

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CUTTING EDGE

Our experts examine the hottest new research

A recipe for a model galaxy Simplicity may be the key to explaining the processes that drive galactic formation WORDS: CHRIS LINTOTT A radically simple approach to explaining galaxy formation based on gas is proving surprisingly effective

the star formation rate. The galaxy maintains a constant star-formation rate, just as the thermostat keeps a house at a steady temperature. So how far does this get us? It turns out that despite its simplicity the model does rather well. It produces a world in which the star-formation rate of a galaxy depends mostly on the mass of stars already in it, just as we observe, and explains how galaxies must have

THINKSTOCK

F

rom our perspective, galaxies seem to be complicated beasts. The interplay between stars, gas, dust and dark matter – not to mention the supermassive black hole lurking in the centre of any respectable galaxy – makes for a complex and confusing environment. A new paper from Simon Lilly at ETH Zurich and friends cuts through this complexity, proposing a simple and attractive model that accounts for many of the observed features in the galaxies around us. The idea is simple; the team suggests that the most important factor in a galaxy’s evolution is the amount of gas available for star formation. This is a radical approach in modern astronomy. The authors admit that they’ve missed out lots of the physics (and chemistry) and hence lots of the processes at play in a real galaxy, but that doesn’t matter. The game here is to create a ‘toy model’ that is well understood, and then think about what it does and doesn’t explain in an attempt to pin down the important omissions. This was common enough more than a decade or so ago, but since then extragalactic astronomers (including myself) have been overwhelmed with data and have spent our time struggling to understand what our observations had to tell us, rather than building models. How do we build a galaxy? The model the team developed starts with a constant flow of gas into the system from its surroundings. The more gas there is, the more stars form. The powerful stellar winds of those stars in turn expel gas from the galaxy, creating a regulated system; if the rate of star formation increases, so does the effect of stellar winds, reducing skyatnightmagazine.com 2013

“The team suggests that the most important factor in a galaxy’s evolution is the amount of gas available”

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

grown over the last 10 billion years. It also accounts for the connection between these properties and the metallicity of the available gas (the proportion made up of elements other than hydrogen and helium). What’s more, as gas is continually entering and exiting the system it’s the present-day conditions that determine what we see today, not a galaxy’s past. That’s particularly profound, as previous models needed a complete record of what’s happened to the galaxy to determine the metallicity. Better still, we get all this information without having to invoke the dark matter halo in which every major system sits. The dark matter is still there, but it’s the movements of normal gas that control what we see. It’s a deeply satisfying result, and I for one will be diving back into messy data to see if this beautiful model can possibly be true.

CHRIS LINTOTT was reading… Gas-regulation of galaxies: the evolution of the cosmic sSFR, the metallicity-mass-SFR relation and the stellar content of haloes by Simon Lilly et al. Read it online at http://arxiv.org/abs/1303.5059

BULLETIN JUNE 15

News in brief

Newborn stars seem to defy gravity ALMA reveals signs of star birth near our Galaxy’s black hole

NASA/JPL-CALTECH/T. PYLE, NASA/MSFC, NASA/CXC/MIT/F.K. BAGANOFF ET AL, THINKSTOCK, NASA/ESA

NASA has selected a new planet-hunting satellite for launch in 2017. The Transiting Exoplanet Survey Satellite (TESS) will look for signs of rocky Earth-like worlds where life could thrive, as well as larger planets such as gas giants. TESS will carry four wide-angle telescopes and will monitor stars to look for the slight dimming that occurs when a planet passes in front. “We will identify many nearby star systems with rocky planets in the habitable zone for further study by telescopes such as the James Webb Space Telescope,” says John Grunsfeld, NASA’s associate administrator for science. The James Webb Space Telescope should launch in 2018.

APOLLO ENGINES FISHED OUT OF ATLANTIC

Two first-stage engines from the powerful Saturn V rockets that sent men to the Moon have been recovered from the Atlantic Ocean by a team led by Amazon founder Jeff Bezos. The engines will be restored for public display.

Sagittarius A*, the supermassive black hole at the centre of our Galaxy, as seen by the Chandra X-ray Observatory

have become so dense that they are able to overcome their inhospitable surroundings,” he says. www.almaobservatory.org

BOOK A PLACE ON AN ASTEROID MISSION

Asteroids are the focus of several planned space missions

Looking back

NASA GREEN LIGHTS NEW PLANET HUNTER

ASTRONOMERS HAVE SPOTTED the signs of star formation unexpectedly close to the supermassive black hole at the centre of our Galaxy. It’s a surprising find, as astronomers suspected that the fearsome gravity of the black hole – which is four million times as massive as the Sun – would tear any clouds of gas apart before they could collapse into newborn stars. Farhad Zadeh from Northwestern University in Evanston, Illinois, and colleagues made the discovery using the ALMA telescope array in Chile. “What we seem to have found are patches of dust and gas that

WOULD YOU LIKE your name immortalised on an asteroid? The Japan Aerospace Exploration Agency is inviting the public to submit their names and messages to be recorded on its Hayabusa 2 spacecraft, due for launch in 2014. Hayabusa 2 will arrive at an asteroid called 1999 JU3 in 2018, investigate the rock and collect a soil sample, then return to Earth in 2020. Your name can be recorded on a marker left on the asteroid and on a memory chip that will make the return trip. The application deadline is 16 July. www.planetary.org/get-involved/messages/ hayabusa-2

The Sky at Night June 1993 On 27 June 1993, The Sky at Night broadcast discussed an upcoming service mission for the Hubble Space Telescope by astronauts on Space Shuttle Endeavour. It aimed to correct an embarrassing problem that had dogged Hubble since its launch from a shuttle in April 1990 – all of its images were fuzzy because engineers had

ground the telescope’s mirror to the wrong shape. The discrepancy was tiny, only about a 1/50th of the thickness of a sheet of paper, but it was catastrophic. NASA planned to dedicate Hubble’s first servicing mission in December 1993 to fixing the observatory’s dodgy vision. During the mission, Endeavour

Hubble has been orbiting 90 Earth since 19 astronauts installed a set of mirrors that successfully corrected the telescope’s focus. NASA released new observations by the revamped Hubble in January 1994 and astronomers were delighted to see the beautiful, sharp images the mission had promised.

skyatnightmagazine.com 2013

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CUTTING EDGE

Our experts examine the hottest new research

When darkness fell on Jupiter’s moons An ancient maelstrom of debris could have created the dark regions on some Galilean moons WORDS: LEWIS DARTNELL Pulverised comets may be the cause of the dark coloured surfaces on Callisto and Ganymede

fragments like a shotgun blast, which smashed into and broke up other objects. Over time, most of the large comet-like bodies were pulverised into grains. And as the grains would have contained a lot of carbon compounds, they were dark in colour, just like comets or carbonaceous chondrite meteorites today. As the authors say, it would have resembled a swirling cloud of coffee grounds.

NASA/JPL X 5

T

he faces of Jupiter’s icy moons hint at a curious story. Io is yellow and smeared with sulphurous deposits from its intense volcanism. Callisto’s icy surface is a dark sooty colour, pockmarked with white impact craters. Ganymede, meanwhile, has dark patches in between paler, newer terrain, and Europa’s dynamic, young surface is the freshest and brightest of them all. The dusky regions represent the most ancient surfaces, which raises the question: what is the dark stuff that smothered the icy moons billions of years ago? William Bottke, at the Southwest Research Institute in Colorado, and his colleagues have published an intriguing possible answer. The established theory is that shortly after the planets formed, gravitational interactions between the outer giants transformed the original architecture of the Sun’s orrery. Jupiter migrated inward while Saturn, Uranus and Neptune were flung outwards, scattering hordes of comet-like objects. This scenario neatly accounts for the current positions of the giant planets and their associated orbital populations (such as the Trojan asteroids leading and trailing Jupiter) as well as the Late Heavy Bombardment that saw the inner planets and our Moon pummelled by asteroids and comets. Many of the scattered comet-like objects were captured, becoming irregular satellites of the giant planets: anomalous, even backwards-orbiting, tiny moons. Bottke argues that these can account for the dark coating of the icy Galilean moons. Around four billion years ago, objects in this cloud around Jupiter ploughed into one another in a destructive ‘collisional cascade’. Each impact sprayed skyatnightmagazine.com 2013

“Each impact sprayed fragments like a shotgun blast, which smashed into and broke up other objects”

Lewis Dartnell is an astrobiologist at University College London and the author of Life in the Universe: A Beginner’s Guide

Such fine grains are subject to another effect, known as Poynting-Robertson drag, a process whereby the absorption of photons of sunlight imparts a minute force against the direction of orbit. It’s a subtle effect, but enough to cause the fine grains to spiral inwards. And as this dusty cloud of grains sweeps through the Jovian system it encounters the Galilean moons, falling like a ‘black rain’ onto their icy surfaces. The outermost moon, Callisto, picks up most of this falling dust – around 25 times more than Europa or Io, Bottke calculates – and so four billion years ago would have been buried under dark drifts over 100m thick. Even for Europa, the authors argue that this mechanism can account for the dark material lying in the moon’s crevices, and may also have provided significant amounts of organic matter for the deep ocean thought to lie beneath its icy crust.

LEWIS DARTNELL was reading… Black rain: the burial of the Galilean satellites in irregular satellite debris by William F Bottke et al. Read it online at http://dx.doi.org/10.1016/j.icarus.2013.01.008

BULLETIN JUNE 17

Carbon may hold key to Martian water

News in brief ENERGY FOR LIFE

Deep carbon compounds could have a huge effect on a planet’s atmosphere ON EUROPA

THINKSTOCK, NASA/JPL/UNIVERSITY OF ARIZONA, NASA/JPL/UNIVERSITY OF ARIZONA, ESO

THE WAY CARBON teams up with other chemicals in a planet’s mantle plays a key role in the evolution of the planet’s atmosphere, a study suggests. The research could help to explain why Mars was once warm enough to have liquid water flowing on its surface. The chemical make-up of a planet’s atmosphere has its roots deep underground. When mantle material melts to form magma, it traps subsurface carbon, releasing it as a gas as it rises to the surface. “We know carbon goes from the solid mantle to the liquid magma, from liquid to gas and then out,” says Alberto Saal from Brown University in Providence, Rhode Island. “We want to understand how different carbon species that are formed in a planet affect the transfer.” On Earth, carbon is trapped in magma as carbonate and emerges into the atmosphere as carbon dioxide gas. How this transfer process happens on other planets is not well understood. However, one key factor involved is the availability of free oxygen. While levels of free oxygen – that is, oxygen that is uncombined with other elements – in Earth’s mantle are relatively high, they are thought to have been low on the young Mars. To find out how this would affect carbon transfer, Saal and colleagues melted volcanic basalts similar to those on Mars using various pressures, temperatures and levels of free oxygen. With low oxygen levels, surprisingly large amounts of carbon

Hydrogen peroxide is plentiful across much of the surface of the Jovian moon Europa, shown below, observations by the Keck Observatory suggest. If it mixes into the liquid ocean that is thought to lie beneath the moon’s crust, it could supply energy for simple lifeforms.

PLANET NAMING SPARKS DISPUTE Mars shows all the signs of flowing water, but none has been found

dissolved and became trapped as iron carbonyl. At low pressures, this iron carbonyl emerged from the rock as carbon monoxide and methane. Both gases are potent greenhouse gases that would have significantly warmed the climate on Mars. That would explain why even a thin atmosphere on the ancient Mars made it warm enough for water to flow, leaving lake beds and river valleys that are visible today. www.brown.edu

IO’S VOLCANOES THROW UP A PUZZLE VOLCANOES ON JUPITER’S moon Io are in the ‘wrong’ place, defying all theoretical predictions. Tidal forces from Jupiter’s gravity flex and distort Io as it orbits, heating its interior and powering extreme volcanism. But now a team led by Christopher Hamilton from the University of Maryland has shown that the volcano distribution doesn’t match that predicted by theoretical models. “Volcanic activity is located 30º to 60º east from where we expect it to be,” says Hamilton, who added that existing models can’t explain the deviation. “Something is missing in our understanding of Io.” www.umd.edu

A heated debate has broken out over the Uwingu project, which is inviting the public to pay to nominate names for exoplanets. The International Astronomical Union (IAU) has issued a statement stressing that it is the sole arbiter of the naming process and “dissociates itself entirely from the commercial practice of selling names of planets”. However, an Uwingu statement replied: “The IAU has no purview – informal or official – to control popular naming of bodies in the sky or features on them, just as geographers have no purview to control people’s naming of features along hiking trails.”

Io doesn’t seem to have any impact craters – it is thought that constant volcanism resurfaces the moon too quickly

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WHAT’S ON JUNE 19

What’s on

Our pick of the best events from around the UK

Visions of the Universe National Maritime Museum, Greenwich, 7 June to 15 September, 10am–4.30pm

PICTHKE

OF MONTH

Dark matters The Bank Hall, Forth, 10 June, 7.30pm Clydesdale Astronomical Society will be delving into some of the Universe’s biggest mysteries this month with the help of Prof Alan Heavens, director of the Imperial Centre for Inference and Cosmology at Imperial College London. Prof Heavens will discuss the unknown forces behind dark energy and the possibility of extra dimensions. Tickets cost £2 per person. www.clydesdaleastro.org.uk

Solar Saturday London Wetland Centre, London, 1 June, 10am Glimpse our star through a solar scope at the London Wetland Centre’s solar observing day, organised and run by telescope dealers Astronomia. They’ll be setting up a selection of solar scopes in the nature reserve’s courtyard so people of all ages can enjoy the Sun in a new way. Throughout the day the company will also be holding improvised planetarium shows in the on-site theatre. www.wwt.org.uk/london

NASA/ESA/AND THE HUBBLE SM4 ERO TEAM, THINKSTOCK X 2, LONDON WETLAND CENTRE

Visit Greenwich to see the history of astro imaging charted using incredible pictures Since we first turned our gaze skyward and began observing the wonders of the cosmos, humans have been inspired by the beautiful yet fleeting sights in the night sky. With the invention of the camera all of this changed: astronomers both amateur and professional have been able to capture and immortalise these amazing spectacles. Opening this month and running until 15 September, the National Maritime Museum’s Visions of the Universe exhibition tells the story of astro imaging

through a collection of over 100 amazing astronomical photographs. Encompassing early daguerreotypes, the latest pictures from the Hubble Space Telescope, NASA’s Curiosity rover and professional observatories worldwide, the exhibition also includes highlights from the Astronomy Photographer of the Year competition. Tickets start at £7.25 per adult and can be booked online through the Royal Museums Greenwich website. www.rmg.co.uk/visions

BEHIND THE SCENES THE SKY AT NIGHT IN JUNE and

One, 2 June, around midnight (repeated Two, 8 June, midday)*

Stars that are massive enough end their lives with a brilliant supernova

Four, 3 June 8pm;

STAR CHRONICLE It can take billions of years for a star to live out its long and tempestuous life. This month, the Sky at Night team visit the Observatory Science Centre in Herstmonceux, East Sussex, to find out more about the stellar life cycle. *Check www.radiotimes.com as times may vary

Cheltenham Science Festival Various locations, Cheltenham, 4-9 June This year’s Cheltenham Science Festival has plenty to offer space enthusiasts, with a range of lectures covering the most current and important topics, from NASA’s Curiosity rover to the elusive Higgs boson. With lectures spread across the city, the festival gives you the chance to learn more about the Universe, from the discovery of recent exoplanets to advances in radio astronomy and more. Ticket prices for each lecture vary, see the website for details. www.cheltenhamfestivals.com

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.

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20

diary Paul Abel gets in a spin as he attempts to demonstrate the motion of the stars around Polaris with a swivel chair, while Pete takes another look at Saturn

BBC, PAUL ABEL X 4

O

ne of the first things I ever saw through my first decent telescope was the planet Saturn. My 4.5-inch reflector transformed an inauspicious point of light into a vision both stunningly beautiful and serenely alien. The yellowish globe looks rather like a muted version of Jupiter, while the planet’s vast ring system has an almost artificial quality to it. Higher magnifications reveal the Cassini Division and the various shadows of the rings and globe. The planet is surrounded by a band of satellites and the whole spectacle looks like you are approaching the planet in a spacecraft. For me, it was the final shove I didn’t know I needed: right then I knew I’d be an astronomer. I have since seen the transforming effects of the sight of Saturn on hundreds of beginners, and many other astronomers no doubt point to it as a source of inspiration. This year, Saturn came to opposition in April, but it will still be visible for a

The society’s good few months after 5-inch Cooke and is the subject of refractor The Sky at Night in May. Saturn is a gas giant, a very different sort of world to Earth. The colourful cloud tops are all we ever see of the Ringed Planet; its mysterious inner depths are always hidden from view. A smog above Saturn’s atmosphere means we perceive it to be a quieter version of Jupiter. As usual, appearances are deceptive, and the planet has thrown us some surprises recently, in particular the powerful and unpredicted Dragon Storm of 2010 which caused so much disruption to the northern hemisphere. For now, Saturn has company in the form of a faithful robotic emissary called Cassini. It is fair to say that this spacecraft has provided us with some truly stunning discoveries.

Demo dilemmas

Hampshire Astronomical Group is based in the small village of Clanfield

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This month’s Sky at Night shoot has been rather spread out and as a result, only part of it – the part with Pete and myself – had been filmed by the magazine deadline. Pete and I were off to meet the Hampshire Astronomical Group in Clanfield, near Petersfield, where we were joined by our regular

newcomers Peta and Steve Bosley, Christina Chester and Paul Williamson, as well as Hampshire Astronomical Group member Becky Collins. This particular shoot required clear skies. We wanted to observe and film Saturn and three fine globular clusters and discuss equatorial mounts using a Sky at Night (ie, inexpensive) demo. As we rumbled out of London Waterloo rail station and I spilled coffee everywhere for the umpteenth time, it occurred to me that we ought to think of an alternative plan; the driving rain had given way to hail and the conditions did not look at all promising! A train ride, two more coffees and a taxi later, and I was at the gates of Hampshire Astronomical Group. I was greeted by chairman Graham Bryant

>

BEHIND THE SCENES JUNE 21

as possible, that I would never be cut out for the space programme. I could barely manage this demo.

Going deeper

she had ever seen such objects. “How would you describe them for the viewers back home?” I asked. “Fuzzy and beautiful,” she replied – brilliant! We closed our section by viewing Saturn through the society’s mighty fine 5-inch Cooke refractor. Pete took some pictures of the planet and I couldn’t resist asking Graham if I could make a drawing of it using their 24-inch reflector. The seeing was poor but I managed to get a sketch. Like the other societies in previous epsiodes, Hampshire Astronomical Group had turned up and enthusiastically supported the program making their telescopes available to us. As we left I realised once more just what a dedicated core group of followers this programme of ours has and how our new format allows them to play an increasingly larger part in The Sky at Night. S

As darkness fell, the bright stars of Orion began to gently shine and e Stev ers Regular newcom in the west. Jupiter Peta Bosely, centre, show off grain and the Moon blazed asse dt-C their new Schim away, and we spotted a couple of sporadic meteors. Eventually Saturn moved up and I was rather surprised at the above the horizon and we were ready to amount of kit they had – five telescope film the next section. Last month we domes and a collection of instruments touched on the basics of observing Saturn, that includes a 24-inch Newtonian and but in this episode we wanted people to a 19th century 5-inch Cooke refractor. look harder at the planet and observe the When everyone had arrived, series finer details. Many of our newcomers producer Jane Fletcher went through were able to make out the North the running order and we decided to Equatorial Belt (which is quite broad film the demo first while there was Society membe at the moment) and see the Cassini plenty of light. Pete had come up with rs turned out in Division. The jet black shadow of the semi-brilliant idea of using a swivel force to support the show the globe on the rings was also chair for this demo (I say semi-brilliant prominent. Christina got her first because it involved muggins here being view of Saturn in a large scope – the spun around in it for several takes!) The Hampshire Astronomical Group’s idea was that if we were at the north pole, 16-inch instrument. Polaris would be practically overhead

VICTOR DE SCHWANBERG/SCIENCE PHOTO LIBRARY

“It occurred to me that I would never be cut out for space. I could barely manage this demo” and the stars (carried by Earth’s rotation) would appear to move horizontally around the pole. The view can be replicated by siting on a swivel chair – overhead there is hardly any motion while everything lower down appears to move around. If we move further south, then the pole is no longer overhead and we have to compensate by tilting the chair so that its axis of rotation points to the pole. This demo works fine provided you’re not the one sitting in the chair, whirling like a dervish! It occurred to me, as Pete whirled the chair as quickly

After Saturn came the globulars. I must admit, I do have a weakness for globular clusters. Very often after I’m done with the planets, I’ll take a look at whichever ones are about. A globular cluster is little more than a massive ball of stars all gravitationally connected, and they form a sort of outer halo around the centre of the Galaxy. Pete had chosen three: M3 in Canes Venatici, M5 in Serpens Caput and, of course, M13 in Hercules. Becky used her new 3-inch telescope, equipped with Go-To technology, to find these hidden gems. This was the first time

THE SKY AT NIGHT IN JUNE One, 2 June, around midnight (repeated Four, 3 June 8pm; and Two, 8 June, midday)*

STAR CHRONICLE It can take billions of years for a star to live out its long and tempestuous life. This month, the Sky at Night team visit the Observatory Science Centre in Herstmonceux to find out more about the stellar life cycle. *Check www.radiotimes.com as times may vary

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22

Interactive EMAILS • LETTERS • TWEETS • CROSSWORD

This month’s Email us at [email protected] 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 2013 is a month-by-month guide to the year and you’ll be able to find all the best sights with Patrick Moore’s Guide to 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.

MESSAGE OF THE MONTH

A smart phone adaptor? Well, if the screw fits... An afocal adaptor for a smartphone can cost in excess of £60 in the shops. I’m very proud to say my dad made me this one in his garage. It’s great for photos and sharing the night sky live amongst a small group while tracking manually. I also wanted to say what a stroke of genius that reader Mark Tissington had about using the iPhone volume control on the headphones to avoid camera shake (April issue, page 22). I look forward to even better images in the future. David Utting, via email

This is fantastic, David. The functional, nutsand-bolts construction of the adaptor contrasts brilliantly with an iPhone’s sleek exterior. – Ed

Drawn to the heavens We amateur astronomers need to be very patient to overcome the frustration of our constantly cloudy and polluted skies. Therefore I look forward to the magazine every month and find the features and observing guides very interesting and helpful. To me personally I am inspired the most by the Sketching section by Carol Lakomiak. This seems to reach out to ordinary amateur astronomers with modest equipment. The articles make me feel as though I am carrying out useful work and I always have a feeling of satisfaction when I have completed my observing and sketching sessions, whether it be a star field, a lunar crater, a galaxy or a nebula. Please pass on my thanks and best wishes to Carol. Your magazine seems to be getting better and better all the time. Thank you for the inspiration. Alan Mark, Middlesborough

Thank you for your support, Alan! Dedicated amateurs such as yourself are an inspiration to us all. Keep up the good work and here’s wishing you clear and steady skies. – Carol Lakomiak

Selsey’s Cave of Wonders With an interest in astronomy fuelled by the later Moon landings I wrote to Sir Patrick Moore in the skyatnightmagazine.com 2013

Þ David’s adaptor is proof that homemade accessories have great value – check out our How to section for more ideas

early 1970s. To my great excitement he invited me to Selsey and my father drove us down. Sir Patrick’s mother supplied drinks and biscuits. After poring over some of the books in his Aladdin’s cave of a study, we went out to look at the heavens. Seeing Saturn and Mars and various nebulae though the telescope I was spellbound, and soon became a young member of the South Downs Astronomical Society (SDAS). Many years later I rejoined the SDAS and was an early supporter of the planetarium now named in his honour. Ross Brand, York

The South Downs Planetarium runs up to 12 public shows a month and has around 12,000 visitors a year. – Ed

Seeing red Since I became interested in astronomy many years ago, I have always been fascinated by the aurora and longed to see it. This year, my wife treated me to a trip to Norway to hopefully see this wonder. On the evening of 3 March, we went on an aurora chase from Tromso, travelling southeast towards Helligskogen – near the Finnish border and well away from any city lights. As soon as we arrived, we could see the light show had already started on the horizon in the northwest. It was a beautiful green curtain

LETTERS JUNE 23

The big

with vertical stripes and my 30-second exposure also shows some red. I also managed to catch M31 in the frame. Half an hour later, the real show started, which was truly amazing. There were explosions of green above us with bands shooting down and spiralling around each other to the western horizon, with Jupiter clearly visible nearby. I was certainly glad my camera didn’t freeze as we recorded temperatures of –16º C on the journey back. It was one birthday I will never forget.

debate

Mike Godsave, Midsomer Norton

Have your say at http://twitter.com/ skyatnightmag

Red auroral displays are a sign of a particularly energetic display, so count yourself lucky Mike! They are caused when charged particles from the solar wind excite oxygen atoms. – Ed

@skyatnightmag asked: How do you prepare for when a gap in the clouds offers an unexpected chance to do astronomy?

> Mike’s shots showcase the beauty of the Northern Lights, including the rarer red rays

@RockersAndrew Be prepared for the George Hole Conundrum. Any object you point at will cloud over when you point your telescope at it!

@scarbastro Normally happens when with a group of cubs, brownies etc.. Just point at something nice so the kids get a look in a scope. @horburyastro Get wife a cuppa to keep her happy, then quickly grab binoculars, camera and tripod and disappear into the Universe!

Here is a pic of me doing some imaging from my home in Exeter. I use my William Optics Z66 and Celestron C6 Schmidt-Cassegrain on a CG5-GT Advanced Go-To mount, with Atik 314L and QHY5 cameras with a filter wheel. I also have a Canon EOS 1000D and a Meade DSI. I have had the setup for about a year and I prefer to image deep-sky objects, especially nebulae. I have both LRGB and narrowband filters and use them frequently. John MacLean, Exeter

We’d love to hear about your scope! Email [email protected]

In the cold seat

@Softspoken_One Have a telescope or binoculars, tripod and star atlas that can be deployed quickly – time is of the essence! @smyth791 With the weather in Ireland, the scope is always on standby. So warm clothes, hot tea and I’m ready to be amazed :)

READERS’ SCOPES

Cast your net wider Forget aperture fever, try wide-field fever! May I say thanks to Stephen Tonkin for his Binocular tour section in April’s Sky at Night Magazine. I started out in astronomy in October last year, when I was bought a Sky-Watcher 130P Newtonian telescope. Since then, I have been guilty of aperture fever. However, with my recent purchase, of a pair of Helios 10x50 binoculars, I have found the beauty of ‘more view’! Armed with the Binocular tour, I went out with my new binoculars and marvelled at the wide-field views of Berenice’s Hair. This inspired me to revisit popular highlights such as Orion’s Belt, the Hyades and Pleiades, and M44, the Beehive Cluster. With a large, 6.5º field of view, I had a new appreciation of the beauty of these objects – not to mention the current ‘star’, Comet C/2011 L4 PANSTARRS. Many congratulations to Stephen on this marvellous new section – long may it continue. Rhys Hardwick, Cardiff

Thank you, Rhys. I am pleased that you have discovered the considerable pleasure of binocular astronomy and I hope to be able to enhance that enjoyment in future issues. – Stephen Tonkin

Firstly can I say, since I have subscribed to this magazine last year, I have thoroughly enjoyed every edition. I saw the blueprints you provided for an observing chair and finally found something I could do, as with my meagre scope most of the observations shown are out of my league. I have finally finished my new observing chair and hopefully this will inspire me to spend more time out in the cold! Alan Beech, Manchester

That solid build looks like it will serve you for many a night to come, Alan. – Ed

Alan’s superb stargazing easy chair

Daytime delight Having been inspired by your article on ‘Spotting Jupiter by day’ (February 2013, page 55) I decided to go a step further and see what sort of daytime image I could get with my 10-inch reflector and > skyatnightmagazine.com 2013

24

The big debate @vickigster My shoes, warm hat and binoculars live by the back door, one sparkle and I’m out there. @AndyWBurns Binoculars kept in the car, small scope and running shoes at home. @andy_ledger I usually grab my birding scope, which is set up with a 30x eyepiece and is enough to see Saturn’s rings and Jupiter’s belts. @KC2VWR_M6UBS Grab the binoculars, tripod, laptop, copy of Touring the Universe though Binoculars and my ham radio portable :) @Tom26Left Have a grab and go, ready to grab and go.

> a DFK21 CCD camera at f/15. This image was taken at 4.20pm on 19 February with a clear blue sky and in full Sun, over an hour before sunset in Oxfordshire. To my great surprise and delight the Great Red Spot is on display! I was unaware that I would be able to image Jupiter, let alone see it through binoculars. Sky at Night Magazine always provides new and interesting things to try. Is there room for a sister publication called ‘Sky by Day’? David Gridley, via email

There’s a nice level of detail in your image, David. While there are currently no plans for a sister publication, we’ll continue to bring you news of noteworthy events visible in daylight. Just remember to be careful when using an unfiltered scope while the Sun is above the horizon! – Ed

Dastardly debris Having witnessed meteor events over the UK in September 2012 and over Russia in February this year (sadly, on the television only!) my attention was drawn once more to the question of orbiting debris. I then noticed that as recently as September last year NASA had considered nudging the orbit of the International Space Station to avoid a potential collision between it and either one of two fragments from an old Cosmos satellite or part of a rocket casing launched by India. In the end this was called off in consultation with all interested parties after the threat assessment was downgraded. What struck me most, however, was that the proposed manoeuvre was solely dependent on using the booster rocket from an attached cargo module. Had that not been docked what other options would there have been?

The Moon and Moore I enjoyed watching The Sky at Night with my brother, whose interest in astronomy led to him becoming a theoretical physicist, and I’ve written a poem about the wonderful Sir Patrick Moore. The Moon and Moore We lost Sir Patrick Moore the other day Larger than life with his mind far away A Betjeman of the Moon and the dark night sky Astronomer Moore and his glass right eye Insistent Moore would suggest that soon ‘We will be landing men on the Moon’ Talking of stars and planets and ploughs It was Moore on the Moon with bushy eyebrows Moore’s clever grey cells pierced glinting eyes His telescope pointing to endless skies Inspiring us from a box in the room To look up and wonder about men in the Moon Peering at the Moon from darkest Selsey Moore played piano to friend Ptolemy Yet ending a grand mortal moonlit trek The clock struck at 89 for Sir Patrick His final exit, the ‘Moon and Mercury’ Was Moore’s longest lasting documentary A lonely Moon dimmed on the 9th of December As Moore went solo we will remember On moonlit nights with a spotlight bright Less is Moore in the sky at night. Sally Ann Hawkes, via email

oxide, the finest particles ever brought back from the Moon. Ed Hengeveld created a superb image. I have been watching The Sky At Night for the last 40 years and met Sir Patrick Moore at Farthings in 2011, which was a great moment for me and my 10-year-old son Yuri. Although English isn’t his mother language, he reads Sky At Night Magazine every month and is already looking forward to the next issue! Philip Corneille, Belgium

Steve Harpin, York

While docked spacecraft are an integral part of providing the thrust for collision avoidance manoeuvres, redundancy is provided by two engines on the Russian Zvezda module. However, luck will continue to play a part until every piece of debris, however small, can be tracked. – Ed

I’m sure that both of these wonderful pictures occupy a prominent position in your home, Philip. – Ed

Remembering Apollo I have been a visual observer of the night sky since 1972, which happened to be the year of the last manned mission to the Moon. In order to celebrate the 40th anniversary of the Apollo 17 mission, I asked Dutch space artist Ed Hengeveld to make a painting of the moment both Moonwalkers discovered orange soil. Astronauts Gene Cernan and Harrison Schmitt sampled the orange volcanic soil, which contained glass spheres rich in iron skyatnightmagazine.com 2013

> Hengeveld’s stunning illustration is shown above; left, 10-year-old Yuri with Sir Patrick

LETTERS JUNE 25

ASTRO CROSSWORD Number 37. Set by PERSEUS

COLUMNIST OF THE YEAR: PAT R I C K M O O R E

Sky at Night Magazine is published by Immediate Media Company Bristol Limited under licence from BBC Worldwide.

EDITORIAL Editor Chris Bramley Features Editor Will Gater Production Editor Kev Lochun Online Editor Kieron Allen Reviews Editor Paul Money ART AND PICTURES Art Editor Steve Marsh Picture Research Sarah Kennett CONTRIBUTORS Paul Abel, Ade Ashford, Rob Banino, Paul F Cockburn Heather Couper, Adam Crute, Lewis Dartnell, Glenn Dawes, Keith Hopcroft, Olivia Johnson, Brian Jones, Carol Lakomiak, Pete Lawrence, Martin Lewis, Chris Lintott, Hazel Muir, Jeff Parker, Mark Parrish, Steve Richards, Paul Sutherland, Stephen Tonkin, Anton Vamplew, Vincent Whiteman, Paul Whitfield, Emily Winterburn, Paul Wootton ADVERTISING SALES Advertising Director Caroline Herbert Advertising Managers Steve Grigg (0117 314 8365), Tony Robinson (0117 314 8811) Inserts Laurence Robertson (00 353 87 690 2208) 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 Head of Licensing and Syndication Joanna Marshall

ACROSS 1 NGC 7000 is more commonly known as the _____ ________ Nebula. (5,7) 7 Site of the comet/asteroid impact which is thought to have wiped out the dinosaurs. (9) 10 Acronym for one of the axes in the equatorial coordinate system. (2) 11 Some observatories consist of a simple roll-off ____ design. (4) 12 Successor to the position of Astronomer Royal after George Airy (surname). (8) 13 ____ Hadley can be seen with an 8-inch telescope under good observing conditions. (4) 14 One of the most volcanic moons in the Solar System. (2) 15 This immense underground experiment is hoping to learn more about the fundamental builiding blocks of the Universe (acronym). (3) 16 Is it a galaxy remnant or a globular cluster? Whichever it is it’s a fine southern hemisphere sight. (5,8) 18 Just beyond the blue end of the spectrum of visible light (acronym). (2) 19 Celestial streak (6) 20 ___ Peake – astronaut from the UK currently training with the European Space Agency. (3) 21 A nebula, galaxy or globular cluster could be one of these (acronym). (3) 22 The _________ Highlands were explored by astronauts during the Apollo 16 mission. (9) 23 _____ Venatici, the constellation that represents a pair of hunting dogs. (5) DOWN 1 It’s not particularly new but it does contain some

fine deep sky sights to observe and image. (3) 2 Boundary within our star. (10) 3 Object from which stars often form. (9,5) 4 Welsh pioneer of astrophotography (surname). (7) 5 Acronym for a vast explosion from the Sun, often responsible for good auroral displays. (3) 6 The large crater Archimedes sits on the edge of this lunar sea. (4,7) 8 A type of telescope mount. (9) 9 Stellar gathering. (4,7) 17 Helping hand inside an electronic mount to guide you around the night sky. (4) 19 Satellite of a planet (4) 21 Not RA but ... (abbreviation). (3)

The solution to this crossword will be published in the July 2013 issue. Astro Crossword number 36 solution

MARKETING Head of Circulation Rob Brock Head of Marketing Marie Davies Marketing Executive Priscilla Midgley Head of Press and PR Carolyn Wray (0117 314 8812) PUBLISHING Publisher Jemima Ransome Managing Director Andy Marshall MANAGEMENT Chairman Stephen Alexander Deputy Chairman Peter Phippen CEO Tom Bureau BBC WORLDWIDE MAGAZINES UNIT Managing Director Nicholas Brett Publishing Director James Hewes Editorial Director Jenny Potter Unit Co-ordinator Eva Abramik EDITORIAL ADVISORY BOARD Nicholas Brett, Tom Bureau, Deborah Cohen, Jane Fletcher, James Hewes, John Lynch, Jenny Potter, Kathy Sykes

SUBSCRIPTION RATES Annual subscription rates (inc P&P): UK cheque/credit card £57; Europe & Eire Airmail £69; rest of world airmail £79. To order, call 0844 844 0260

© Immediate Media Company Bristol Limited 2013 ISSN 1745-9869

All rights reserved. No part of 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 resold, 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.

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.

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28

Hotshots This month’s pick of your very best astrophotos PHOTO OF THE

MONTH

p NGC 891 PETE RICHARDSON SOMERSET, 8 SEPTEMBER 2012 Pete says: “This has to be my favourite edge-on galaxy. I love the dramatic dust lanes, bright central region and overall symmetry this galaxy displays. It’s certainly one I will return to again and again in the future.” Equipment: Orion Starshoot Pro V2 one-shot colour CCD camera, Meade LX200-ACF 12-inch reflector Sky at Night Magazine says: “The details and colours Pete has captured in the dusty disc of this enigmatic galaxy are superb. We particularly like the nicely balanced star colours and the handful of galaxies that are visible in the background.” About Pete: “Astronomy has been an interest since childhood, mainly due to my late father who had a keen interest in the subject. He helped to fire my sense of wonder in all things astronomical. Just over two years ago I built my own observatory, which was the best thing I ever did to support my love of astro imaging. I enjoy both deep-sky and planetary work.”

skyatnightmagazine.com 2013

p Star trails NICK RICHARDSON, VICTORIA, AUSTRALIA, JANUARY 2013 Nick says: “This image was taken with a pretty full Moon, but I like the almost-daylight feel to it. I also like the softness of the ocean giving the image an overall serenity. It was great to go out for the night with just a camera and a tripod instead of the usual gear.” Equipment: Canon EOS 1100D DSLR camera, Tokina 11-16mm lens

HOTSHOTS JUNE 29

The aurora borealis STEVEN MCCONNACH THURSO, 17 JANUARY 2013 Steven says: “This picture shows a nice but short-lived aurora on 17 January. It was a very nice sight in the sky, I just wish it had lasted longer.” Equipment: Canon EOS 500D DSLR camera

The Pleiades  BOB FRANKE, ARIZONA, US, JANUARY 2013 Bob says: “It took eight nights to accumulate the 670 minutes of LRGB data for this winter classic. The Pleiades is probably the most famous cluster in the sky and is easily visible with the naked eye. However, it is best viewed with binoculars or a small telescope.” Equipment: SBIG STF-8300M CCD camera, Takahashi 106ED telescope, Baader LRGB filters, Losmandy G11 mount

▲ The International Space Station MARK WHITE, CHESTERFIELD, 19 FEBRUARY 2013 Mark says: “This image is probably one of my favourite astro photos. I had always wanted to capture the ISS and the Shuttle but unfortunately never managed to get the latter, so this more than makes up for it. I’m impressed by the detail I managed to capture with a small 6-inch mirror, especially the capsules and labs.” Equipment: DMK monochrome CCD camera, Sky-Watcher Explorer-150PDS Newtonian reflector, 2x Barlow lens, Sky-Watcher HEQ5 Pro mount

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 The southern Milky Way DENNIS RADERMACHER RANGITATA VALLEY, NEW ZEALAND, 15 DECEMBER 2012 Dennis says: “The warm starlight in this shot of the Milky Way and the Southern Cross are beautiful reminders of the warm summer night I spent out watching the skies over the New Zealand backcountry.” Equipment: Fuji FinePix X100 digital camera

 Solar filament ANDRÉ VAN DER HOEVEN, THE NETHERLANDS, 17 FEBRUARY 2013 André says: “The filament shown in this image covers more than a quarter of the Sun’s disc, giving it a length of over 300,000km – longer than 20 planet Earths placed side-by-side. Knowing this image is a once in a lifetime opportunity makes it very special for me.” Equipment: DMK 21AU618.AS CCD camera, Lunt LS60T solar telescope, LS75 double stack etalon

The Rosette Nebula  MATT FOYLE, DERBYSHIRE, 20 FEBRUARY 2013 Matt says: “Due to the blanket of cloud covering the UK in early 2013, I’d only been out twice when I captured this image. This target has been a labour of love since I started imaging a year ago and it has turned out much better than I had ever hoped, given the conditions.” Equipment: QHY9M CCD camera, 80mm doublet refractor, HEQ5 Pro mount

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HOTSHOTS JUNE 31

The Carina Nebula  DAVID TROTTER, AUSTRALIA, FEBRUARY 2013 David says: “The Carina Nebula and its surroundings cover an enormous area with so much going on, so it was a perfect subject for the wide-field view my Takahashi FS-60CB presents.” Equipment: Modified Canon EOS 30D DSLR camera, Takahashi FS60CB refractor

▲ The Horsehead Nebula region LUIS ARGERICH, ARGENTINA, NOVEMBER 2012 Luis says: “I like the beautiful red nebulae that can be found all around Orion. It’s an area of the sky that really has the ‘wow’ factor when you take a long-exposure with a digital camera.” Equipment: Canon EOS 60Da DSLR camera, 400mm lens, AstroTrac mount

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Explore

the lunar

domes

Pete Lawrence shows you how to track down these enigmatic volcanic features on the Moon’s surface

N

NASA/GSFC/ARIZONA STATE UNIVERSITY

ext time you train your scope on the Moon, see if you can spot a lunar dome. These shield volcanoes, about 2-25km in diameter, are just a few hundred metres high. Seeing them can be a bit of a challenge: the lighting needs to be just right and from the side to pick out their subtle bulges. The lunar domes are believed to have formed during the later stages of the Moon’s

volcanism. Lava welling up from fissures in the lunar seas smoothed over many of these cracks. As the lava cooled, decreased flow rates and lava crystallisation caused material to build up around flowing vents. The result is the domes we see today, with pits at the top that represent the now inert vents. Read on to see some of the finest lunar domes and discover top tips on how to image them.

ABOUT THE WRITER Pete Lawrence is a reporter on The Sky at Night. He writes The Sky Guide each month, including the regular Moonwatch column.

Craters may be easier to spot but lunar domes are just as interesting to observe

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1

Hortensius dome field 

Size: 6-10km Best time to see: Three days after first quarter or two days after last quarter Minimum aperture: 4 inches The Hortensius dome field contains six great targets. It is located just south of the midpoint of a line joining the 95km-wide Crater Copernicus and 32km-wide Crater Kepler. Copernicus forms a right-angled triangle with 15km-wide Crater Hortensius and 49kmwide Crater Reinhold, which is southwest of Copernicus. Reinhold marks the right angle. Crater Hortensius isn’t too difficult to identify and is the key to locating the domes that lie immediately to its north. The Hortensius domes are subtle and require oblique lighting to be seen properly. They are arranged in three pairs with Hortensius Omega, located immediately north of Crater Hortensius, being the easiest to spot. Four of the domes have a single central vent pit, one has two and the last has none. These pits are small, measuring around 1-1.5km across. You will need a 10-inch scope, good conditions and a magnification of 200x or more to see them.

COPERNICUS

MILICHIUS

Milichius Pi

Hortensius dome field HORTENSIUS

KEPLER REINHOLD



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Milichius Pi

PETE LAWRENCE X 6, NASA/GSFC/ARIZONA STATE UNIVERSITY

Size: 10km Best time to see: Three days after first quarter or two days after last quarter Minimum aperture: 4 inches From Crater Hortensius, head north through the Hortensius dome field and you will arrive at a mountain complex. Slowly move up the western edge of the complex to locate 14km-wide Crater Milichius. Immediately to the west of the crater is an impressive 10km-wide dome known as Milichius Pi. At around 230m in height this feature is, like most domes, quite subtle in appearance but thanks to the relatively barren surrounding region it does stand out well under oblique illumination. You may be able to spot the dome’s 1km-diameter central pit through a 10-inch or larger scope under good conditions. There is no official naming convention for lunar domes. The Greek letter designation that is used for many, including Milichius Pi, was dropped by the International Astronomical Union with no alternative system being offered in its place. skyatnightmagazine.com 2013

LUNAR DOMES JUNE 35

RIMA MARIUS

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3 2

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5

DOME LOCATOR

MARIUS



3

The Marius Hills

Size: Region approximately 170km by 170km, typical dome size 5-15km Best time to see: Five days after first quarter or four days after last quarter Minimum aperture: 4 inches Marius Hills

REINER

 4 Cauchy domes Size: 12km Best time to see: Five days after new Moon or four after full Moon Minimum aperture: 4 inches The 14km-wide Crater CAUCHY Cauchy is located in the eastern region of Mare Tranquillitatis (Sea of Tranquility) and is surrounded by fascinating lunar geology. Tau There’s a rille, or crack, Omega to the north of the crater and an impressive 120km-long fault line, known as Rupes Cauchy, to the south. The region also contains a number of subtle domes that become much easier to see at lunar sunrise or sunset. The two most prominent of these domes are Tau and Omega, which lie to the south and southwest. Omega has a well-defined 1km central pit, which may be visible in larger instruments.

The Marius Hills are an extensive set of lunar ‘bumps’ close to the 43km-diameter Crater Marius in the Oceanus Procellarum (Ocean of Storms). It has the highest density of volcanic features of any single region on the Moon. Like all domes, these 200-500m features are best seen at low illumination and show up well in contrast to the smooth surrounding surface of the Ocenaus Procellarum. The northern end of the bright albedo feature known as Reiner Gamma passes through the Marius Hills.

Arago domes 5

Size: 20-24km Best time to see: Five days after new Moon or four days after full Moon Minimum aperture: 2 inches

Arago Beta

Arago Alpha

The 27km-wide Crater Arago is located in the western part of Mare Tranquillitatis. Despite its diminutive size the crater is full of detail, including a terraced rim and a ridge-like central mountain reaching out to the rim. There are two large domes close by. Arago Alpha is 24km across and reaches a height of around 300m. It is easy to see if the lighting is oblique, which will also emphasise the fact that the dome is lumpy rather than being typically smooth. Arago Beta lies to the west of Arago and, at 20km across, has a similar lumpy appearance to Alpha.

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MAIRAN SINUS IRIDUM

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Gamma

Delta

Zeta

GRUITHUISEN

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Mons Gruithuisen Gamma

Size: 20km Best time to see: Three days after first quarter or two days after last quarter Minimum aperture: 2 inches The easily identified Sinus Iridum (Bay of Rainbows) is the key to locating these domes. The bright highland region south of the bay terminates in two distinctive mounds called Mons Gruithuisen Gamma and Delta. A third mound, known as Zeta, can also be seen south of the other two. Gamma, the western and most prominent mound, is 20km across and rises to a height of 900m. Its appearance has earned it the rather unflattering but apt nickname of the 'upturned bathtub'. It appears foreshortened and somewhat rectilinear with rounded corners. On its top, there’s a 2km craterlet. The 17km-wide Crater Gruithuisen lies 110km to the south of Mons Gruithuisen Gamma.

Capuanus domes

PETE LAWRENCE X 5, NASA/GSFC/ARIZONA STATE UNIVERSITY, PAUL WHITFIELD

Size: 6-10km Best time to see: Three days after first quarter or two days after last quarter Minimum aperture: 4 inches Capuanus is a 61km-wide crater on the southern shore of the Palus Epidemiarum (Marsh of Epidemics). For dome hunters the crater is a godsend because the three main domes associated with Capuanus are all located within its rim. This should make them easy to locate, but there’s a trade off because the best time to spot them is at low illumination, when the shadow cast by the crater walls can obscure the domes. If you try to see them when the crater rim shadows are at their shortest, the high angle of incoming light means the domes all but disappear from view. There are six domes here in total; the other three are less easy to spot. They range in size from 6-10km.

KIES

Kies Pi



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Kies Pi

Size: 10km Best time to see: Two days after first quarter or one day after last quarter Minimum aperture: 4 inches The 46km-wide Crater Kies lies in the western portion of the Mare Nubium (Sea of Clouds). The crater itself is relatively easy to identify, as it looks like a vanity mirror complete with handle. To the west of Kies lie two distinctive 49km-diameter craters: Campanus and Mercator. An impressive dome known as Kies Pi lies about a third of the way along a line joining the centres of Kies and Campanus. This is a classic lunar dome, approximately 10km in diameter and rising to an estimated height of around 150m. This isn’t very high compared to its diameter so, like many of these features, you’re looking for a subtle swelling of the lunar surface. The dome is virtually invisible under high illumination, but stands out well when close to the terminator. A small 2km crater pit sits centrally in the dome.

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LUNAR DOMES JUNE 37

9

Lansberg D domes

Size: 15km Best time to see: Two days after first quarter or one day after last quarter Minimum aperture: 4 inches Draw a line from Copernicus, through Reinhold to the southwest, and you’ll eventually arrive at 41km-wide Crater LANSBERG D Lansberg. Keep the line going and you’ll arrive at the flooded, 20km Crater Lansberg C. A short hop of 65km southwest then brings you to a bright, 10km crater known as Lansberg D. Under low illumination it is possible to see two large broad overlapping domes approximately 25km to the southeast of Lansberg D. Numerous wrinkle ridges, formed from raised buckled lava, can also be seen nearby under oblique illumination and these really add drama to the scene.

 10 Mons Rümker Size: 70km Best time to see: Five days after first quarter or four days after last quarter Minimum aperture: 4 inches Mons Rümker resembles a giant raspberry poking through the northwestern part of the Oceanus Procellarum. It is a circular mound, 70km in diameter. but it looks elliptical due to foreshortening. The 900m-high mound is covered in approximately 30 lunar domes, extending the formation’s overall height to 1,100m. This mega-dome complex is unique on the Moon and, taken as a whole, represents the largest dome-related feature on the lunar surface. High-resolution images of the region reveal a number of tiny vent pits visible on the tops of some of the domes. S

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DOME LOCATOR IMAGING LUNAR DOMES

Domes make great imaging targets, best captured when lighting is oblique. A large-aperture scope and high frame rate camera will deliver the best results, but a DSLR and small scope may still record them against the adjacent lunar surface. Adding an infrared pass filter to a monochrome high frame rate camera may help to stabilise the view. Don’t use an infrared pass filter if your camera is already infrared-blocked, however, as between them these two filters will cut out all wavelengths and the camera won’t see anything. Focus carefully then capture several hundred frames at least. Process the images you capture using registration and stacking software such as RegiStax, AutoStakkert! or AviStack. If you capture an image of a lunar dome or any other lunar feature, be sure to submit it to the Astronomy Photographer of the Year competition at www.rmg.co.uk/astrophoto.

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38

A DECADE OF

DISCOVERY

Kev Lochun looks back at the science and success of Mars Express after 10 years in orbit around the Red Planet

skyatnightmagazine.com 2013

I

t was put together using blueprints from past missions and was only supposed to last for two years, but this month marks a decade of Mars Express, ESA’s first mission to another planet. Five operational extensions and more than 10,000 orbits later, it continues to beam data back to Earth. In engineering terms, Mars Express represented a tested approach, its basic design borrowed from ESA’s comet-bound Rosetta probe and some of its instruments reused from the failed Russian Mars 96 mission. With the conceptual work largely done, ESA was able to complete the orbiter for €150 million and in record time, with the mission moving from approval to launch in only five years. The spacecraft began its journey on 2 June 2003, shattering the tranquillity of the Kazakh steppe as it roared into the sky with the ill-fated Beagle 2 lander in its clutches. Also on board were instruments to examine the Red Planet’s surface, study its atmosphere and search for subsurface ice. Mars was a much greater enigma then than it is today; Giovanni Schiaparelli’s 19th century sketches of ‘canals’ may well have been relegated to fantasy artwork, but astronomers were still on the hunt for water, wherever it might have been. The probe arrived at Mars six months later, entering orbit on Christmas Day. In late January 2004, ESA called a conference: barely a month into its mission, the craft had already returned proof of water-ice on Mars’s south polar cap. Such an early triumph was a sign of things to come, with the little orbiter going on to confirm the presence of methane in the atmosphere, detect the Martian aurora and produce a near complete map of the planet. Here we celebrate those successes by looking back at some of the finest images it has returned.

Kev Lochun is Sky at Night Magazine’s production editor. Before becoming a journalist, he gained a degree in biology from Cardiff University.  OCTOBER 2010 Earth’s deeper recesses lie under roiling oceans, but on Mars they are much easier to explore. The rifts and pit-chains seen here are the Coprates Chasma and Coprates Catena, which feed into the extensive Vallis Marineris canyon system.

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ESA/DLR/FU BERLIN (G. NEUKUM)

ABOUT THE WRITER

40

MARS EXPRESS MISSION TIMELINE 2 June 2003 – Launched from Baikonur Cosmodome in Kazakhstan atop a Soyuz-FG/Fregat rocket

ESA/DLR/FU BERLIN (G. NEUKUM) X 3, LLUSTRATION BY MEDIALAB/ESA 2001

JANUARY 2004 With an average elevation of 22km, Olympus Mons is the largest volcano in the Solar System. At its summit sits this nested caldera complex, a collection of six collapsed craters that formed in the aftermath of eruptions on the Martian surface. The plain on the left side of the complex, riddled with tectonic faults, is thought to be the oldest, with each subsequent caldera destroying its outline little by little.

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19 December 2003 – Jettisons Beagle 2 towards the Martian surface; the little lander is never heard from again

25 December 2003 – Completes its 400-million-km journey and enters orbit around the Red Planet

10 YEARS OF MARS EXPRESS JUNE 41

23 January 2004 – Finds evidence of water at Mars’s south pole using its visible and infrared spectrometer

28 January 2004 – Enters science orbit, with an orbital period of 7.5 hours. Orbit was adjusted after 440 days, reducing the period to 6.7 hours

30 March 2004 – Discovers methane in the Martian atmosphere, sparkling speculation that it may be from organic or volcanic sources

JULY 2012  Red marks the highest points and purple the lowest in this colourised terrain image of 154kmwide Gale Crater, the landing site of NASA’s Curiosity rover. Curiosity was targeting a landing ellipse of 25km by 20km, the smallest of any previous Mars mission, but using data from Mars Express and other orbiters NASA scientists were able to reduce the landing zone to a tiny 20km by 7km.

 SEPTEMBER 2011 Water once flowed in Eberswalde Crater, the scant remains of which can be seen on the right of this image. Only a small portion of the 65km-wide impact crater’s rim is visible, but the presence of an alluvial fan – a cone-shaped deposit of sediment – on its floor indicates that there was once a river delta here. Dominating the left of the frame is the much larger, younger and easier to see Holden Crater.

THE BEAGLE HAS FLOUNDERED Not every dog has its day. There were high hopes for the UK-developed Beagle 2, so high in fact that it was named for the same ship that took Charles Darwin on the round the world voyage that ultimately led to his theory on natural selection. In this instance, Beagle 2, a late addition to the Mars Express mission to maximise its scientific returns, would be the ‘ship’ that carried a brace of sensors and tools to the surface to analyse Mars’s soil and look for life within it. Alas, nominative determinism failed to have any influence on the lander’s

fortunes. Beagle 2 separated from Mars Express on 19 December 2003 and was expected to signal NASA’s Mars Odyssey orbiter to confirm its arrival six days later. The signal never came. All attempts to re-establish contact were met with silence and it was eventually declared lost in February 2004. To date, neither lander nor crash site has been found. Had it successfully parachuted to the surface, as illustrated right, the saucer-shaped lander would have opened up like a flower, revealing the solar panels that would have powered its experiments.

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42

MARS EXPRESS MISSION TIMELINE

ESA/DLR/FU BERLIN (G. NEUKUM), NASA/JPL/ASI/ESA/UNIV. OF ROME/MOLA SCIENCE TEAM/USGS, ESA/DLR/FU BERLIN (G. NEUKUM); IMAGES PROCESSED BY F. JANSEN (ESA), HTTP://SPACEINIMAGES.ESA.INT/IMAGES/2012/01/ANCIENT_NORTHERN_OCEAN_ON_MARS

9 June 2005 – ESA reports that ‘light emissions’ recorded by Mars Express in August 2004 are the first Martian aurorae

August 2006 – Detects rare cloud layer at an altitude of 80-100km – the clouds appear to be carbon dioxide ice

▲ MARCH 2007 This radar map, combined with topographical data from NASA’s Mars Global Surveyor, reveals the thickness of ice-rich layered deposits at the Martian south pole, with purple areas being the thinnest and red the thickest – deepening from tens of metres at the edges to more than 3.7km. This is nearly pure water-ice, with little Martian dust mixed in. The black circle represents a latitude of 87ºS, beyond which the orbiter’s radar is unable to collect data.

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16 November 2007 – Delivers the first global map of the Martian ionosphere, revealing unexpected activity

10 YEARS OF MARS EXPRESS JUNE 43

25 May 2008 – Relays data to help NASA land the Phoenix lander – it only survived for few months, but is still considered a success

3 March 2010 – Makes its closest flyby of Martian moon Phobos, passing just 67km above the odd satellite’s surface

19 December 2010 – ESA extends the mission for a fifth time, confirming that operations will continue until the end of 2014

 AUGUST 2011 This bright cap, glistening at Mars’s north pole, is waterice – we know this because the shot was taken during Martian summer, a time when it is sufficiently warm that any carbon dioxide ice would sublimate away. The dark streak threatening to split the cap is Chasma Boreale, a canyon with 2km-high walls; the dark material within it may be volcanic ash.  JULY 2003 Eight million kilometres into its journey, Mars Express was pointed back towards Earth to take this farewell shot of our planet and the Moon. Even from this distance, the clouds hanging over Earth’s northern hemisphere are as clear as day.  FEBRUARY 2013 Mars Express is tantalisingly close to mapping the entire Martian surface. This mosaic, made up of 2,702 swaths, or strips, represents 87.8 per cent of the Red Planet. Although the map has been equatorially aligned, causing distortion near the poles, many of Mars’s most recognisable features are visible – look out for Olympus Mons, top left, and the trio of volcanoes that form the Tharsis Montes, just right of centre.

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44 10 YEARS OF MARS EXPRESS JUNE

MARS EXPRESS MISSION TIMELINE June 2012 – After nearly 11,000 orbits, Mars Express has mapped nearly 90 per cent of the planet

6/7 August 2012 – Relays data to help NASA land the Curiosity rover in Gale Crater

The future – Mars Express will continue to map the Red Planet and make its closest ever pass of Phobos

▲ MAY 2012 Coloured topographical images can reveal the history of Martian features. While some craters in this shot of the Tempe Terra and Acidalia Planitia appear to have steep walls, others appear no deeper than the surrounding landscape – suggesting they are older and have been filled in over time.

THE EXPERT Olivier Witasse is the current project scientist for the Mars Express mission

ESA/DLR/FU BERLIN (G. NEUKUM) X 2

Has the Mars Express orbiter met the hopes that ESA had back in 2003? Mars Express exceeded its expectations. I don’t think anybody thought that it could work for so long. These 10 years have allowed us to map Mars in almost all seasons, illuminations and locations. What Mars Express discovery has surprised you the most so far? One of the most interesting and unexpected was the detection of carbon dioxide ice clouds. These clouds are a key component of the atmosphere and may have had an impact on the early Martian climate. Their formation mechanism has not yet been identified – it’s still a mystery that we need to decipher. Is Mars still the most exciting place to look for life in the Solar System? I think that Mars is one of the most

skyatnightmagazine.com 2013

exciting places. Other planetary missions or observations have revealed other worlds worth a visit, like Titan or Enceladus, but clearly Mars is the closest one! The mission has been extended to the end of 2014; what can we expect from it up until then? The next exciting milestone will be the closest ever Phobos flyby on 29 December 2013, at 58km from the centre of the moon. From September 2014, it will work with NASA’s MAVEN spacecraft to find out how Mars’s atmosphere is lost into space and how to relate this to the evolution of its climate. How has the probe influenced subsequent ESA missions? It will be useful for the ExoMars orbiter: a logical follow-up mission with the goal of detecting very fine amounts of gases in Mars’s atmosphere. Mars Express findings will certainly be used to select the landing site of the ExoMars rover.

▲ JULY 2008 Phobos, the larger of Mars’s two irregular moons, hangs above the Martian limb in this eerie shot. It was once thought to be a captured asteroid, but data about its composition collected by Mars Express suggests it may may have formed in Mars’s orbit, perhaps as a result of an impact on Mars itself. S

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THE SKY GUIDE JUNE 47

June The Sky Guide

Night-shining beauty

OUR STARGAZING EXPERTS

As we head towards the middle of the year, now is a great time to keep a lookout for rare noctilucent or ‘night-shining’ clouds. These are the highest clouds in our atmosphere, which glow because they reflect sunlight from our star when it is below the horizon.

PETE LAWRENCE As well as writing The Sky Guide, Pete can be seen on BBC TV’s The Sky at Night. On page 60, he explains how to photograph a noctilucent cloud panorama.

PETE LAWRENCE

STEPHEN TONKIN When he’s not doing astronomical outreach of one form or another, Stephen heads to the New Forest to observe the night sky. Take his Binocular tour on page 58. STEVE RICHARDS Steve is passionate about observing deep space and likes nothing more than taking images of distant galaxies – follow his Deep-sky tour on page 56 to find a host of fascinating objects. skyatnightmagazine.com 2013

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

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SATURDAY Mercury, Venus and Jupiter can be seen low in the northwest after sunset. The three planets form a straight line, with mag. –0.2 Mercury on the upper left and mag. –1.8 Jupiter on the lower right. Venus, in the middle, is the brightest, shining at mag. –3.8.

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SUNDAY  The Keystone asterism in Hercules is due south, about 70º up at 01:00 BST (00:00 UT). This is the location of fabulous globular cluster M13. From tonight until the 16th is a good time to take this month’s Deep-sky tour – see page 56.

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THURSDAY  This is a good time to keep watch for the Milky Way. At around 01:00 BST (00:00 UT) from a dark sky site, our Galaxy can be seen cascading down the sky from overhead to the southern point on the horizon.

SUNDAY The weak Ophiuchid meteor shower reaches the first of two peaks this evening, and with the Moon out of the way at the moment this a good time to try and spot a meteor. The shower has a peak zenithal hourly rate of five meteors per hour.

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 TUESDAY At 20:40 BST (19:40 UT), the waxing gibbous Moon (72% lit) will be 45 arcminutes from mag. +1.0 star Spica (Alpha (a) Virginis). The Moon is in the lower half of the southern sky; Spica is just above it. The pair are easier to see later on when the sky is darker.

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PETE LAWRENCE X 8

SATURDAY With the Moon now almost full, look out for the Moon illusion over the next few nights. The Moon can look huge when it is full and low down, as occurs at this time of year. In reality, its size remains more or less the same, the effect being an optical illusion. See page 51. WEDNESDAY The rather unpredictable June Boötids meteor shower peaks tonight. The normal zenithal hourly rate is one or two meteors per hour, but in 1998 the shower showed an unexpected peak of 100.

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SUNDAY  Today’s full Moon is the largest of the year with an apparent diameter of 33 arcminutes and 28 arcseconds.

FRIDAY The Teapot asterism in Sagittarius is low down, very close to the southern horizon at 01:00 BST (00:00 UT).

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WEDNESDAY Mag. +1.3 Mercury and mag. –3.8 Venus are 2º apart this evening. Visible low in the northwest, wait for an hour after sunset to allow the sky to darken sufficiently to see Mercury. You’ll need a flat northwest horizon for this.

20

THURSDAY The weak Ophiuchid meteor shower reaches its second peak of the month tonight. The waxing gibbous Moon (89% lit) will interfere. Expect a peak zenithal hourly rate of about five meteors per hour.

THE SKY GUIDE JUNE 49

What the team will be observing in June Pete Lawrence “I’m going to be on the lookout for noctilucent clouds. Hunting them down can become something of an obsession. Thankfully, the short nights do mean I’ll get some sleep!”

5 10

WEDNESDAY With the Moon now slipping out of the way, keep vigil after sunset for noctilucent cloud displays. These appear as shimmering electric-blue clouds glowing in the twilight to the northwest after sunset or northeast prior to sunrise. See page 51.

Stephen Tonkin “Ophiuchus is now well placed and, among its many fine binocular objects, I will be renewing my acquaintance with planetary nebula NGC 6572, the greenest visual object in the night sky.” Will Gater “I’m going to be seeking out a dark-sky site with a very clear southern horizon this month to image reflection nebula IC 4592 in Scorpius.”

MONDAY  Mag. –3.8 Venus sits low in the west-northwest just after sunset with mag. +0.5 Mercury 0.5º to the left. If you can see it, look out for the delicate waxing crescent Moon (4% lit) about 7.5º to the lower-left of Venus.

Terms you need to know BRITISH SUMMER TIME(BST)/UNIVERSAL TIME (UT) Events are given in British Summer Time (BST), with Universal Time (UT) in brackets. BST is one hour ahead of GMT; UT is the same as GMT.

21

FRIDAY At precisely 06:04 BST (05:04 UT), the Sun will reach its highest point in the sky for the year. Known as the summer solstice, this represents a point in time when the northward apparent movement of the Sun in the sky comes to a halt, followed immediately by a change in direction to the south. The almost full Moon lies just less than 6º to the north of mag. +1.1 orange star Antares (Alpha (a) Scorpii) this evening.

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

Icons explained

How to tell what equipment you’ll need NAKED EYE Allow 20 minutes to become dark-adapted BINOCULARS 10x50 recommended PHOTO OPPORTUNITY Use a CCD, webcam or standard DSLR SMALL SCOPE Reflector/SCT under 150mm, refractor under 100mm

29

SATURDAY Dwarf planet Pluto is due south at 01:00 BST (00:00 UT), roughly midway between open cluster M25 and mag. +3.5 Xi2 (x2) Sagitarii. Pluto itself is mag. +14.0, so you’ll need a large scope (around 12 inches) to see it, given its altitude and the lack of truly dark skies. See page 50.

30

SUNDAY Saturn ends the month less than 0.5º from mag. +4.2 star Kappa (k) Virginis.

LARGE SCOPE Reflector/SCT over 150mm, refractor over 100mm

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.

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50

SCUTUM

M16

γ

DON’T MISS... 3 TOP SIGHTS

Path of Pluto during June

M18

HIP 91903

υ

M25

ρ1

μ

ξ1

Teaspoon

M17

HIP 92079

π ο

29

Dwarf planet Pluto

M22 M8

λ φ

σ

δ

τ

WHEN: 1-19 June

SAGITTARIUS

PLUTO LOST ITS major planet status in 2006, when it was demoted to the new class of dwarf planet. Despite this it has remained in the limelight, with new moon discoveries – the count has reached five so far – and it being the target for the New Horizons probe, scheduled to arrive there in July 2015. For amateur astronomers, Pluto represents something of a challenge. Being so distant it appears pretty faint. As it reaches opposition on 2 July, Pluto will only be mag. +14.0. There are many seasoned observers who would dispute the common claim that you

need a large telescope to see Pluto. Conventional wisdom states that a 12-inch or larger scope is needed, but some hold that it’s been seen in instruments with apertures as small as 4.5 inches. The smaller you go, the more important good optics, excellent dark adaptation and a clear, dark sky become. Unfortunately for us in the UK, it is difficult to find those clear, dark skies given Pluto’s location, low down in the constellation of Sagittarius. Imagers fare better and even modest scopes coupled to a DSLR camera

M21 M20

ξ2

γ

M54

ζ

Teapot

M69 M70

ε

M7

S

Viewedfrom: Localtime: Fieldof view: Magnitudes: 14.0 12.0 10.0 8.0 6.0 4.0 Star Central British 00:00:00 Isles 01∞ 24' 22.5" star 02∞ 30' 00.0" 2013/06/18 W Azimuth (∞):Multiple 163.1182∞ 54∞ 00' 00.0" JD 2456461.50 N Altitude (∞): Variable +14.8513∞ star

Use the Teaspoon asterism to work your way towards the dwarf planet

can normally get down to the magnitude required to catch it. Identifying the planet is simply a matter of drawing or imaging the field of view over several nights. If you see something move between recordings that may well be Pluto. It is relatively easy to locate the region of sky Pluto occupies during June and early July thanks to the distinctive Teapot asterism that lies at

TYC 6288-843-1 (mag +9.9)

TYC 6288-925-1 (mag +9.0)

21 Jun

11 Jun

1 Jun

Pluto

6 Jul

GSC 6288 1616

PETE LAWRENCE X 4

(mag +13.9)

SAGITTARIUS

N E

HIP 92079

TYC 6288-557-1 HIP 91903

Pluto moves through Sagittarius through the month; the positions above are correct for 01:00 BST (00:00 UT)

skyatnightmagazine.com 2013

NEED TO KNOW

The International Astronomical Union recognises five dwarf planets in the Solar System; the others are Ceres, Eris, Makemake and Haumea.

the heart of Sagittarius. Northeast of the Teapot is another small asterism, appropriately known as the Teaspoon. Two of the Teaspoon’s stars, mag. +3.8 Omicron (o) Sagittarii and mag. +3.5 Xi2 (x2) Sagittarii, point to a 5th-magnitude star called 29 Sagittarii. Keep following this line to arrive at mag. +6.3 HIP 92079 (also TYC 6288-1145-1) and mag +6.7 HIP 91903 (TYC 6288538-1), both easily visible in a finderscope. Once located, refer to the chart on the left to identify the highlighted triangular pattern connecting these stars with the pair TYC 6288-843-1 and TYC 6288-925-1, which are mag. +9.9 and mag. +9.0 respectively). Pluto will pass through this region over the course of the month. The rest, as they say, is up to you. Don’t forget to give your eyes at least 20 minutes in complete darkness before you attempt to look for the dwarf planet. It is always interesting to hear just how small an aperture it is possible to spot Pluto with, so do write in and let us know!

Viewedfrom: Localtime: Fieldof view: Magnitudes: 6.5 5.6 4.6 3.7 2.7 1.8 Star Central British 00:00:00 Isles 45∞ 00' 00.0" star 02∞ 30' 00.0" 2013/06/18 W Azimuth (∞):Multiple 163.4227∞ 54∞ 00' 00.0" JD 2456461.50 N Altitude (∞): Variable +09.8020∞ star 30-arcminutes

1 Jul

!

THE SKY GUIDE JUNE 51

A bigger full Moon than usual WHEN: 20-27 June for the Moon illusion, 22 and 23 June for the perigee full Moon

THE MOON IS full on 23 June at 12:32 BST (11:32 UT). As events go, this isn’t particularly special as the Moon is typically full at least once during the course of a month. However, this Moon is slightly different as it is a perigee full Moon – one that occurs as the Moon is at the closest point in its monthly orbit around Earth. The June full Moon coincides with the closest perigee of the year. Our natural satellite will have an apparent size larger than average at 33 arcminutes and 28 arcseconds across. Compare that with the December 2013 full Moon, which will occur three days from apogee – the time when the Moon is at its farthest point from Earth in its orbit. On 20 December, the full

Moon will be 29 arcminutes and 25 arcseconds across. To put it another way, the December full Moon will be 12 per cent smaller than the one on 23 June. The summer full Moon never gets particularly high in the sky as seen from the UK. This introduces another point of interest, as a low full Moon is in the best location to show off the so-called Moon illusion, the effect where the Moon looks artificially bigger than it actually is. Catch the full Moon rising and it’ll typically look much larger than normal. However, hold your little finger up at arm’s length and, amazingly, you can hide the Moon’s disc with ease. If you’re wondering whether the perigee full Moon on

June’s full Moon is low on the horizon, a great position for the Moon illusion

23 June will have any adverse effects, there is no need to panic. Although it’ll look marginally brighter and larger than the other full Moons of the year, you probably wouldn’t even

notice the difference if you didn’t know about it in advance. As for whether we’ll survive its passage across the sky, consider that the perigee full Moon in March 2011 was slightly larger.

The bright blue hue typical of noctilucent clouds gives them an ethereal appearance

Noctilucent cloud watching WHEN: 22:00-00:00 BST (21:00-23:00 UT) looking northwest, 02:00-04:00 BST (01:00-03:00 UT) looking northeast

FROM THE END of May through to the start of August the temperature in the atmospheric layer known as the mesosphere falls to its lowest for the entire year. If it drops below –120ºC, rarefied water vapour can form micron-sized ice crystals around tiny dust particles most probably left over from meteor events. Collectively, these ice crystals form a thin reflective layer 76-85km up, capable of reflecting the light cast by the Sun when it is between 6º and 16º below the horizon. These are noctilucent clouds. They hang on the edge of the twilight arc during summer and their reflected light often appears an electric-blue colour. Normal clouds, on the other hand, exist up to heights of 20km and appear dark under similar conditions.

There is no guarantee that noctilucent clouds will appear at all, but the best times to look for them are from 22:00-00:00 BST (21:00-23:00 UT), when they may appear low in the northwest and north, and from 02:00-04:00 BST (01:00-03:00 UT) where they may be visible low in the northeast and north. A bright display is a sight not easily forgotten and can start in the

northwest, slowly pass through the northern sky and end up in the northeast sky as dawn starts to break.

!

NEED TO KNOW

Noctilucent clouds form in the mesophere at an altitude of around 80km – the edge of space – making them the highest type of cloud to exist over Earth.

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52

THE PLANETS Pick of the month 10th

VENUS

15th

BEST TIME IN JUNE:

1 June, 22:00 BST (21:00 UT) ALTITUDE: 6º (low) LOCATION: Taurus DIRECTION: Northwest RECOMMENDED EQUIPMENT:

20th 25th

30th

Mercury 1st

15th

10th

Venus

1st 10th

FEATURES OF INTEREST:

Jupiter

Moon

Phase, subtle shadings VENUS IS RETURNING to the evening sky but its appearance is being hampered by poor timing. The bright summer nights are not much of a problem – at mag. –3.8, Venus is able to blaze through even the brightest of twilights and can even be seen in broad daylight if you have keen eyes and know where to look. The difficulty that threatens to keep this most brilliant of planets under wraps is the plane of the Solar System, which is marked out by a great circle in the Venus is so bright it remains visible in June’s bright twilight

5th

5°

Naked eye, 3-inch or larger telescope

5th

1st

NW

Mercury, Venus and Jupiter form a straight line on the 1st; positions correct for 22:15 BST (21:15 UT)

sky known as the ecliptic. The major planets all occupy orbits that lie close to the ecliptic, so their visibility greatly depends on its angle and height relative to the horizon. In the spring months, the ecliptic makes a steep angle with the western horizon after sunset, but this decreases markedly as we head into summer. Consequently, the height of Venus above the horizon after sunset isn’t the best at the moment. As we head into autumn, the angle gets even shallower and Venus will tend to hug the horizon. At the start of the month we find the planet sandwiched between mag. –1.8

Jupiter below and to the right, and mag. –0.2 Mercury above and to the left. If you are able to train a telescope on Venus, you’ll see that its 10-arcsecond disc currently appears almost full with a 96% phase. Over the following months, as we head into autumn, Venus will lurk close to the horizon after sunset. This is the result of the shifting position of the ecliptic. Do not be deterred by this, as such a brilliant beacon in the sky does create some interesting opportunities. For example, look out for the waxing crescent Moon (4% lit), which will be 7.5º below and to the left of Venus on 10 June.

How the planets will appear this month The phase, tilt and relative sizes of the planets in June. Each planet is shown with south at the top, to show what it looks like through a telescope

MERCURY 1 JUNE

SATURN 15 JUNE

VENUS 31 JUNE

URANUS 15 JUNE

PETE LAWRENCE X 2

MERCURY 15 JUNE

MERCURY 30 JUNE

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NEPTUNE 15 JUNE

MARS 15 JUNE JUPITER 15 JUNE

0”

10”

20” 30” 40” ARCSECONDS

50”

1’

THE SKY GUIDE JUNE 53

SATURN BEST TIME IN JUNE:

1 June, 23:30 BST (22:30 UT) ALTITUDE: 25º LOCATION: Virgo DIRECTION: Just west of south Saturn is just past its highest point in the sky as darkness falls. It is in Virgo, close to mag. +4.2 star Kappa (k) Virginis. If you follow Saturn throughout June, you’ll see it closing on the star until, by 30 June, the separation is less than 0.5º. The planet is around mag. +0.5, slightly brighter than nearby mag. +1.0 star Spica (Alpha (a) Virginis). They are separated by 12º but, by virtue of their similar brightness they look like a pair. Observe Saturn through a scope and you’ll see a fine display, as its rings are tilted open by around 17º. JUPITER

The planet reaches greatest eastern elongation on 12 June, when it will be separated from the Sun by 24º. Telescopically it shows a small, 8-arcsecond disc, slightly gibbous in shape. Mercury’s position doesn’t improve during June but it does get closer to Venus. URANUS

NEPTUNE BEST TIME IN JUNE:

30 June, 01:00 BST (00:00 UT) ALTITUDE: 7º LOCATION: Aquarius DIRECTION: East-southeast Distant Neptune is slowly drifting back into our skies, but is hampered by the lack of true darkness at this time of year. Its mag. +7.8 dot should be visible in binoculars, not too far from the mag. +4.8 star Sigma (s) Aquarii. MARS

MERCURY BEST TIME IN JUNE:

12 June, 30 minutes after sunset ALTITUDE: 9º LOCATION: Gemini DIRECTION: Northwest Mercury forms a line with Venus and Jupiter after sunset at the start of June. At mag. –0.2 it is the faintest of the three, but as it tops the line it has the virtue of being higher in the sky.

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

BEST TIME IN JUNE:

30 June, 02:30 BST (01:30 UT) ALTITUDE: 12º LOCATION: Pisces DIRECTION: East Uranus is slowly crawling back into the morning sky. Currently in Pisces, it forms the lower point of a right-angle triangle with mag. +4.3 star Epsilon (e) Piscium and mag. +4.4 star Delta (d) Piscium. Uranus is a dimmer mag. +5.8 – you’ll need binoculars to spot it in the bright June skies.

BEST TIME IN JUNE:

1 June, 30 minutes after sunset ALTITUDE: 3º LOCATION: Taurus DIRECTION: Northwest We lose Jupiter to the Sun this conjunction with our star on 19 June. You can grab a final view of the gas giant at the start of June when it is in conjunction with Venus and Mercury, but its low altitude will make it difficult to see, despite being mag. –1.8. After conjunction, Jupiter re-emerges into the morning sky.

Saturn’s moons

BEST TIME IN JUNE:

30 June, one hour before sunrise ALTITUDE: 3º (very low) LOCATION: Taurus DIRECTION: Northeast Mars isn’t well placed at the moment, being close to the Sun. Early risers at the end of June may just be able to catch its mag. +1.5 pinkish disc very low above the northeast horizon just before sunrise.

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

SATURN IN JUNE DATE

WEST

EAST

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 01 3

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On other dates, use the interactive planetarium on our website at www.skyatnightmagazine.com/interactive-planetarium

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CHART CONVERSION BY PAUL WOOTTON

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skyatnightmagazine.com 2013

OPHI

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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.

M

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When to use this chart How to use this chart

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THE SKY GUIDE JUNE 55 β

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Key to star charts

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CONSTELLATION NAME

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DEEP-SKY TOUR With Steve Richards

an 8- to 10-inch telescope at 200x magnification its irregular disc will become apparent as an angular core with four lobes surrounded by a matching shaped halo. Images of this fascinating object show a likeness to the shape of a swimming turtle.  SEEN IT

Colourful doubles, globular cousins and a celestial smoke ring adorn the June sky ✓ 

Tick the box when you’ve seen each one

3 The Double Double, top left, forms a triangle with Vega and Zeta Lyrae

4

CHART: PETE LAWRENCE, PICTURE: STEVE RICHARDS

1

2

STRUVE 2264

We start this month’s tour in Hercules with the beautiful colour-contrasting double star Struve 2264. It comprises mag. +4.9 95 Herculis A and mag. +5.2 95 Herculis B, and as they are separated by 6.4 arcseconds they can be split with an 8-inch telescope at about 200x magnification. The primary is silver-blue, which contrasts subtly with the yellow-white of its companion, although the seasoned English astronomer and admiral William Smyth described the colours as light applegreen and cherry-red in his own Bedford Catalogue. Imagine a line drawn from mag. +2.8 star Zeta (ζ) Herculis through mag. +4.4 star Maasym (Lambda (λ) Herculis) and extended just under the same distance again to locate the pair.  SEEN IT

NGC 6210

From Struve 2264 draw an imaginary line to another binary star, mag. +3.1 Sarin (Delta (δ) Herculis). Now draw a second line between Sarin and mag. +2.8 star Kornephoros (Beta (β) Herculis). Five-eighths of the way along and 1.5º above the line lies our second object, tiny planetary nebula NGC 6210. Just 16 arcseconds across, the nebula appears as a blue-green dot in a small telescope. Through

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5

6

M13

Our next object is the magnificent globular cluster M13, the ‘jewel’ in this constellation and the most famous globular cluster in the northern hemisphere. From NGC 6210, return to Zeta Herculis, the star at the bottom right corner of the Keystone asterism, then draw an imaginary line to the star at the top right of the asterism, mag. +3.5 Eta (η) Herculis. You’ll find M13 about two-thirds of the way along. A 3-inch telescope at low magnification will show a bright, circular smudge of light, but an 8- to 10-inch telescope will reveal numerous stars in strings radiating outwards from a bright core.  SEEN IT

M92

M92 is often overlooked because of the relative closeness of M13 – its brighter cousin – but it is just as beautiful. This globular cluster appears to be very slightly oval with a north-south orientation. Even through a small telescope, its non-stellar appearance will be quite obvious even though its core is somewhat more compact than that of M13. It is a fine sight in an 8-inch telescope, through which myriad stars will become visible. To locate the cluster, continue from M13 to Eta Herculis, then imagine a line from there to mag. +3.8 star Iota (i) Herculis. The globular can be found just under two-thirds of the way along.  SEEN IT

THE DOUBLE DOUBLE

Leaving Hercules, hop eastwards to brilliant, mag. +0.0 blue-white star Vega, the alpha star in the constellation of Lyra. Vega lies 1.75º to the southwest of our next target, Epsilon (ε) Lyrae, also known as the Double Double. It is the most northerly member of an equilateral triangle of stars, with the other positions filled by Vega and mag. +4.3 Zeta (ζ) Lyrae. It is readily apparent that Epsilon Lyrae is a double star through binoculars. However, it hides a secret that is revealed as you start to increase the magnification to around 100x. Through a 4-inch or larger telescope, you’ll be able to see that each star is a double in its own right.  SEEN IT

THE RING NEBULA

Our final object is the delightful Ring Nebula, M57, which has the appearance of a celestial smoke ring suspended in space. From the Double Double, slide 6.5º south to find mag. +3.5 star Sheliak (Beta (β) Lyrae), which marks the foot of the parallelogram of stars below Vega. Now imagine a line east-southeast towards mag. +3.3 star Sulafat (Gamma (γ) Lyrae). The Ring Nebula is located about a third of the way along and just below this line. Visible in a 3-inch telescope as a slightly elongated disc, a 10-inch telescope will reveal some darker regions near the disc’s edge and traces of faint nebulosity within.  SEEN IT

+30º

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(δ) Ophiuchi) and mag. +2.5 Zeta (ζ) Ophiuchi as its other points. At 75 lightyears wide, M12 is one of the larger southern globulars and an easy spot in moderately good skies through 10x50 binoculars. Like all globular clusters, it benefits from averted vision, with which they appear to both brighten – especially towards the core – and get bigger.  SEEN IT

BINOCULAR TOUR With Stephen Tonkin Ophiuchus offers up some fine star clusters – including a Hyades lookalike ✓ 

10 x Open cluster Melotte 186 (also designated 50 Collinder 359) is centred on mag. +3.9 67 Ophiuchi. It is a large, relatively sparse cluster, spanning 4°, so is nicely framed in the field of a pair of 10x50 binoculars. Look for the V-shape of five 4th- and 5th-magnitude stars: its resemblance to the Hyades in Taurus was the reason that 18th century Lithuanian astronomer Marcin Odlanicki Poczobutt proposed this region of the sky as the constellation of Taurus Poniatovii – Poniatowski’s Bull, named for a king of the now-defunct Polish-Lithuanian Commonwealth.  SEEN IT

2 NGC 6633

15 x If you extend the left leg of Melotte 186’s 70 V a further 7° to the northeast, you will reach NGC 6633. This marvellous cluster is often overlooked in lists of binocular objects because it can be tricky to find, but it is easily visible in a pair of 10x50s. However, a pair of 15x70s will resolve more stars – depending on your skies,

you should see between 15 and 20 of them against the background glow of the rest of the cluster. Larger binoculars should also bring out the yellowish colour of some of them.  SEEN IT

3 THE SUMMER BEEHIVE

10 x The Summer Beehive (IC 4665) is in the 50 same field of view as Cebalrai (Beta (b) Ophiuchi). This large cluster is delightful in binoculars of any size and you should be able to resolve a dozen or so stars with a pair of 10x50s. It is the object that welcomes you to the summer skies: look for a particularly attractive curved chain of bright white stars which forms part of the letter H of the inverted word ‘HI!’. This is a relatively young cluster, being less than 40 million years old  SEEN IT

15 x Mag. +7.6 globular cluster M14 lies 70 approximately 6° (one and a half 15x70 binocular fields) west of mag. +4.6 star Zeta (ζ) Serpentis. This is a moderately easy object in 15x70 binoculars. With averted vision it will not only appear to grow in size and show the brightening of the core, but may also reveal a slightly triangular appearance. This latter effect, which is much easier to see if you mount the binoculars, is an optical illusion that is caused by the faint strings of stars that seem to run from the cluster’s southeast and southwest peripheries.  SEEN IT

10 x Mag. +6.6 globular cluster M12 is close to 50 the northeast apex of an equilateral triangle that has orange mag. +2.7 star Yed Prior (Delta

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skyatnightmagazine.com 2013

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CHARTS AND PICTURES: PETE LAWRENCE

6 M14

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HERCULES

E

10 x The easiest way to find M10 is to 50 navigate from M12. If you place M12 in the northwest of your field of view, M10 should appear near to the opposite side, approximately the same size but half a magnitude fainter. Averted vision shows a very distinct brightening of the core compared with M12. The bright star to the east of the same field of view is mag. +4.8 30 Ophiuchi; if your sky is dark enough, you can use this star as a guide to the location of the cluster.  SEEN IT

Tick the box when you’ve seen each one

1 MELOTTE 186

5°

5 M10

M80

THE SKY GUIDE JUNE 59 N

E

MARE FRIGORIS

ARISTOTELES

MITCHELL

EGEDE EUDOXUS MONTES CAUCASUS

MARE SERENITATIS

Aristoteles TYPE: Crater SIZE: 87km wide AGE: Between 1.1 and 3.2 billion years old LOCATION: Latitude 50.2°N, longitude 174°E BEST TIME TO OBSERVE: Six days after new Moon (evening of 14 June) or five days after full Moon (from 00:00 BST on 29 June or 23:00 UT on 28 June) MINIMUM EQUIPMENT: 2-inch refractor

Crater Aristoteles sits between two lunar seas, forming a conspicuous duo with Crater Eudoxus

MOONWATCH With Pete Lawrence “To the casual lunar observer it is easy to dismiss one crater as looking like another, but with patience it is possible to see all manner of detail” CRATER ARISTOTELES CAN be found in the northeast quadrant of the Moon’s Earth-facing side. It sits on the southern shore of the Mare Frigoris, not too far from the Vallis Alpes, the northern end of which is just 200km to the west. To the casual lunar observer it is easy to dismiss one crater as looking like another, but with patience it is possible to see all manner of detail, which gives each its own unique character. Aristoteles is similar in size to the impressive Crater Tycho in the Moon’s southern highlands. Despite evidence of radial features surrounding Aristoteles’s rim, these lack the dynamic brilliance of those found around Tycho, leading to the

conclusion that Aristoteles must be older because its rays have faded due to being exposed to space-weathering for longer. It is worth noting that darker rays aren’t always an accurate indicator of age as geological make up has an effect too. The inner wall of this 87km-wide crater is very detailed and shows interesting variations. The walls to the north, east and south have many terraces leading down from the crater’s rim top to the floor 3.5km below. The western rim is different, showing a steep scarp slope leading down to a collection of hills at floor level. The crater floor itself is relatively flat but there are several mountain peaks scattered

across the crater. Aristoteles is shallower than Tycho, presumably having been partly filled in with material. Interestingly, this isn’t the dark mare lava you would expect, so the true nature of the floor in-fill isn’t totally understood. If you manage to catch the crater just before the Sun has had time to illuminate its floor properly, it is possible to pick out at least one of these mountain tops glinting against the dark floor. The 31km-wide Crater Mitchell adjoins Aristoteles, its western rim overlaid by the larger crater. However, under oblique lighting conditions, look carefully at the eastern rim of Aristoteles – the remains of Mitchell’s rim can still be seen making a faint impression. The Montes Caucasus extend up towards Aristoteles, passing to the west of the prominent 67km-wide Crater Eudoxus, which lies some 166km south of Aristoteles. Eudoxus and Aristoteles form a pair on this part of the Moon’s surface, although this is really by proximity rather than similarity. Also of interest is the 37km-wide Crater Egede. This represents what’s left of a crater when its inner floor has been flooded with dark lava – all that remains is its outer rim and a flat floor littered with a few craterlets. skyatnightmagazine.com 2013

60

ASTRO PHOTOGRAPHY With Pete Lawrence

Night-shining clouds Recommended equipment DSLR with a wide- or mid-angle lens, tripod, remote shutter release cable

DURING JUNE WE’RE in the heart of the noctilucent cloud hunting season. They present an interesting challenge to catch with your camera and add a bit of excitement to the shortest nights of the year. They are also timed perfectly to book-end a night of observing. Noctilucent clouds, commonly referered to as NLCs, are the highest clouds in Earth’s atmosphere, forming in a narrow layer within the mesosphere 76-85km up. Photographing them is actually quite straightforward, requiring little more than a tripod-mounted camera with a wideangle lens. If your camera has manual control options, the lens should initially be fully opened (low f/number), set to manual focus and pre-focused at infinity. The camera should be set to a reasonably high ISO, around 400-800, and be capable of exposures of up to 10 seconds.

The most difficult aspect of imaging NLCs is getting into the habit of actually looking for them in the first place. This may sound obvious, but their typically low altitude often means that they can be easily hidden behind buildings or trees. Finding a location with a flat northwest to north horizon for a pre-midnight hunt and a flat north to northeast horizon for the dawn watch is imperative. Noctilucent clouds appear in the summer months, between late May and early August, when the temperature at the NLCs’ altitude falls below –120 º C. If this sounds cold, it is – in fact, it is the coldest place on Earth. The clouds form from water vapour condensing on tiny fragments possibly left behind from meteor trails. As a meteoroid – the name given to the typically sand-grain

sized pieces of rock that eventually become meteors – passes through the atmosphere, it vaporises at a height typically 75-100km up. The tiny fragments left in the atmosphere are now believed to be a contributing factor in seeding the formation of NLCs. So if you were worried that we’d stepped over the threshold into weather forecasting, don’t worry – there is a solid link with astronomy! How the water vapour gets up there is more complex and is now thought to be the result of some complicated chemistry, possibly connected with climate change. So when you see a beautiful display of NLCs, it may be something of a doubleedged sword in that it may also be an indication that something unusual is happening to our climate. This also adds a layer of scientific importance to observing and imaging them – so make sure you mark the date and time on any photos you capture, as well as recording the location from which you took them.

A glimmer on the horizon NLCs shine because they are high enough that they reflect the sunlight even when our star is between 6º and 16º below the horizon. In this state, normal ‘tropospheric’ clouds remain in darkness. If any of these clouds pass through the scene when a bright NLC display is in full swing, they can produce interesting effects of their own, appearing silhouetted against the bright and much higher NLCs. NLC displays vary in intensity from very weak, hardly discernible wisps to

ALL PICTURES: PETE LAWRENCE

Creating an NLC panorama

STEP 1 Identify your NLC spotting sites. For evening NLCs you need somewhere with a relatively flat and dark view of the north and northwest horizons; it’s the same for morning NLCs but facing north and northeast. Aim to check the evening site between 22:00-00:00 BST (21:00-23:00 UT) and the morning site between 02:00-04:00 BST (01:00-03:00 UT).

skyatnightmagazine.com 2013

STEP 2 Imaging NLCs requires nothing more complicated than a camera on a tripod, though we’d recommend a remote shutter release cable so you can take shots without wobbling the camera. The camera needs some manual settings for you to get the best shots, but a big NLC display may be bright enough for basic point and shoot or camera phones to record.

STEP 3 The tripod should be on level ground and the camera aligned so that the bottom edge of the image frame is parallel to the horizon. Once you’ve done this use the tripod to pan the camera left and right to make sure it doesn’t wander up or down from the horizon. If you’ve got it right, the bottom of the image frame and the horizon should remain parallel.

THE SKY GUIDE JUNE 61

The Moon makes NLCs harder to see, but it is still possible to capture strong displays like this one in its presence

full-on glowing networks of electric-blue clouds bright enough to spark erroneous reports that the aurora is visible. If you get a full-on display then you may be able to rely on some of your camera’s automatic functions, for example auto-focus. To start, take a 5-second test exposure with the ISO set at 800 and examine the result on your camera’s review screen. If it is too bright and contains white, then the image is overexposed. Use your camera’s histogram display (if it has one) to confirm this. The histogram will show a sharp ‘cliff’ at the white end of the graph if the image is overexposed. If the cliff is shown towards the black end of the histogram – in other words, if the image contains black – then it is underexposed. To correct overexposure, drop the ISO or the exposure time. You could also try stopping your lens down by a stop or two. Dropping the ISO has the advantage that the delicate tones of the scene should render better. To correct for

underexposure increase the ISO or the exposure time. Increasing exposure is preferable to increasing ISO in this case, as the latter will reduce tonal quality and increase image noise. In order to catch a good display, you’ll need to be vigilant and look out each evening and preferably in the morning too. Fortunately, the short nights of June and July don’t make this too much of a chore and there’s still time for a

STEP 4 Aim your camera at one extremity of the display and include a bit of silhouetted horizon for scale. Take a shot. Using something on the horizon as a guide, move the camera sideways into the display, keeping an overlap of 25 per cent between frames. Take the next shot and repeat until you capture the entire display. If the display is high, consider taking portrait shots.

STEP 5 You can join the images together manually in your favourite editor, but a simpler method is to download a freeware panorama creator such as Microsoft’s Image Composition Editor, which is available from http://bit.ly/ICE_mosaic. Once installed, the display files can be dragged into the program’s main window and it will then do all the hard work for you.

good amount of sleep even after the morning watch. Although the presence of a bright Moon will make NLCs harder to see, the waning crescent phases may be positioned so that the Moon’s disc is behind an extensive display. If this occurs, the thin-film nature of the NLC layer amazingly doesn’t do much to the moonlight that passes through it – there is no real scattering of light around the Moon’s disc.

Key technique USE THE RIGHT TOOL FOR THE JOB

If you do get to see a noctilucent cloud display this summer there is a good chance that the scene will be too wide for your camera. With your camera levelled, it is a relatively easy job to take the shots necessary to create a panorama of the display. Although this can be done manually (by carefully making sure you keep a bit of silhouetted horizon in the shot) there’s an automated method using the free-to-download Microsoft Image Composite Editor that can really take the hard work out of the process.

 Send your image to: [email protected]

STEP 6 If the NLC display is bright enough, you may be able to record an image with the panoramic imaging function on a smartphone. In any case, camera phones continue to improve in quality, so if you don’t have a regular camera it is worth trying your phone to see if you can record the display. Don’t forget to send your results in for our Hotshots gallery – see page 28.

skyatnightmagazine.com 2013

ESO/B. TAFRESHI, KIERON ALLEN

TO THE ENDS OF TIME WITH

The constellations of Vela and Carina sparkle in the pristine skies above the Atacama Desert

The author with the Atacama Compact Array

Kieron Allen travels to Chile’s remote and inhospitable Atacama Desert to report on the official inauguration of ALMA, the most ambitious ground-based array in history

C

hile’s Atacama Desert is a hostile place. Until 1971, some areas of this parched, barren landscape hadn’t seen rain in over 400 years. As somewhere to live the Atacama Desert leaves a lot to be desired but, for astronomers, its arid, high-altitude Chajnantor Plateau has proven to be the ideal location upon which to build one of the world’s most advanced telescopes.

On 13 March, amid the desert’s sweeping plains, the Chilean president, Sebastián Piñera, made an impassioned speech to an international crowd of astronomers and delegates. Under piercing blue skies in this remote corner of South America, the president welcomed the latest addition to Chile’s growing armada of super scopes. “This is the best expression of the will of human kind to learn more about the

Universe,” announced Piñera as he officially opened the Atacama Large Millimeter/submillimeter Array, otherwise known as ALMA, the world’s largest astronomical project. But why the presidential seal of approval? Well, if ALMA – the highest and most-complex telescope array on the planet – achieves even a small percentage of what it’s expected to, it will allow us to peer deeper into the early Universe >

The combined observing power of ALMA’s antennas can produce higher resolution images than Hubble

HOW ALMA WORKS 1

< Each of the 66 antennas in the ALMA array collects faint millimetre and submillimetre waves using their large dishes.

þ The analogue signal

is detected by sensitive receivers and digitised before being sent through up to 16km of fibre-optic cable.

þ Signals from all the antennas

are combined in ALMA’s correlator, generating astronomical data.

3

> than ever before. And in so doing, it may help answer some of the fundamental questions about the formation of the cosmos. Built at an altitude of 5,000m, high in the Chilean Andes, the ALMA site offers outstanding atmospheric transparency, a vital quality when searching for faint millimetre and submillimetre wavelengths of light. Visiting such great heights on our ascent to ALMA the crippling effects of altitude sickness were a constant threat, so we were provided with a personal supply of oxygen – a supply that was quickly exhausted on the slow, winding bus journey up to see the telescope array. When ALMA eventually becomes fully operational (at the moment there are around 50 working dishes), the data from 66 antennas – 54 with a diameter of 12m and 12 with a diameter of 7m – spread over 16km will be combined, turning the individual telescopes into an interferometer,

2

> This data is sent a few kilometres

down to the Operations Support Facility, then on to the ALMA office in Santiago and ALMA regional centres around the world for analysis.

4

Þ Although most of ALMA’s 12m antennas have

been installed, a few are still under construction

skyatnightmagazine.com 2013

ALMA JUNE 65

FINDING ALMA Located at 5,000m, ALMA is the world’s highest astronomical observatory. But as well as its staggering altitude the site is also incredibly isolated, thousands of kilometres from the Chilean capital Santiago. It is nestled on the southern fringes of the Altiplano – the Andean Plateau – the place where the Andes are at their widest. Town Observatory

Venezuela Colombia Ecuador Peru Brazil

Th e An

es

d

a single, virtual antenna far bigger than anything it would be possible to build. The entire array is pointed at the same patch of sky and each antenna moves in unison with the next in a surreal, astronomical ballet. With so many sensitive antennas, the resolution of ALMA’s images will be much higher than from any other existing radio telescope. But in achieving this high level of resolution, astronomers have sacrificed the main array’s ability to make more complete wide-field observations. With ALMA’s dishes spread so far apart (from the centre of the site it’s impossible to see all of the array’s widely spaced antennas) there are distinctive gaps in the telescope’s images. To compensate for this, the smaller 7m telescopes and four of the 12m telescopes programmed to work independently from the interferometer are positioned closer together in a separate arrangement called the Atacama Compact Array (ACA). The four 12m scopes also work independently from their smaller counterparts in the ACA. The results from this array are much lower in resolution but capture a far wider view of the sky. All of the data from the ACA and the rest of the 12m antennas in the main array is eventually combined to create a complete ALMA image.

Bolivia The Altiplano Paraguay

A lot more to see Argentina Santiago

Chile

Uruguay ATACAMA DESERT

Bolivia Calama ALMA

Antofagasta

Chile

þ ALMA’s isolated

location offers perfect observing conditions

Argentina

why exploring this tiny band of light is so important. “The millimetre-wavelength band offers us a lot of information,” he says. “As astronomy is an observing science and we can do nothing more than look. Whatever information we can get is important and this frequency range contains a lot. It’s like opening a new window on to the Universe. “We’re all used to optical waves; our eyes are used to the stars. But if our eyes were able to see millimetre waves we would, for example, see a really bright, giant molecular gas cloud in the constellation of Orion. What we can’t see with our eyes, we can see with ALMA.”

Out in the cold ALMA will concentrate on observations of the ‘cold’ Universe. These are areas not yet heated by the immense energy from the formation of stars and galaxies. By examining these locations ALMA scientists are hoping to find answers to some very > skyatnightmagazine.com 2013

KIERON ALLEN X 7

ALMA is scouring the Universe for millimetre and submillimetre waves. These elusive wavelengths of light are found in a narrow band on the electromagnetic spectrum just a few millimetres wide, between far infrared and radio waves. In the past, scientists have had to rely on space telescopes to make these observations, as it is difficult for such light to penetrate Earth’s thick, moisture-laden atmosphere. But the Atacama Desert’s aridity makes the atmosphere more stable and transparent above ALMA, so it’s possible to image these wavelengths at 10 times the resolution offered by the Hubble Space Telescope. It is an incredible feat when you consider the calibre of images Hubble has beamed back over the years. At the array’s inauguration, we spoke to ALMA European project manager Wolfgang Wild to learn

66

> big questions. “We’d like to find out how stars

form and why they form the way they do,” says Wild. “We want to learn how planetary systems form, which would tell us whether our system is special or just average. Then, of course, there’s the chemistry; all the building blocks for life are there in the cold Universe. Does that mean life has to emerge once all the right elements are in place?” ALMA’s applications are impressive – eventually the mammoth array will even be used to create high-resolution images of exoplanets – and so too is the technology that will make any future discoveries possible. Each dish in the ALMA array is a highly accurate instrument, so exact in its

Þ The back end of one of ALMA’s antennas is put through its paces in the OSF’s on-site laboratory

movements that it can align with an object the size of a golf ball from 15km away. They are the most precise antennas ever produced and can maintain their shape to within a fraction of the thickness of a human hair despite the often extreme Andean weather (on our visit the temperature at the high site was over 20°C cooler than at ALMA’s base camp). It is this precision that allows them to see the faint light of millimetre and submillimetre waves. When this light hits the surface of a dish it is channelled into the centre of the antenna and detected by a receiver. Each antenna has 10 separate receivers, all geared up to detect radio waves of different lengths, from 0.3mm to 10mm. Once a signal has been picked up it is channelled, under most circumstances, into superconductor-isolatorsuperconductor (SIS) mixers. The SIS mixers convert the signal from a frequency of up to 900GHz to a range of between 4GHz and 10GHz, so that it can be easily managed by the electronic circuits in the antenna’s amplifiers. It is at this stage that the waves are amplified for the first time since being detected. The antennas’ receivers are cryogenically cooled to a few degrees above absolute zero (–273°C) in order to make the signals clearer and provide the optimum working environment for their superconductive elements. After passing through the receiver, the signal is converted from an analogue format into a digital one before being encoded and transmitted down fibre-optic cables to join the signals from the other antennas in ALMA’s correlator. The correlator, housed in the Array Operations Site Technical Building – the second-highest

THE EXPERT

KIERON ALLEN X 3, ALMA (ESO/NAOJ/NRAO)/M. KORNMESSER (ESO), S. CASASSUS ET AL.

Thijs de Graauw was ALMA Director from 2008 until just after the observatory’s inauguration. He told us some of the challenges faced in getting ALMA off the ground Why was ALMA built? It was the detection of molecules in space at the end of the 1970s that started it. By 1982 the US had the Millimeter Array. This was shortly followed by projects in Japan and Europe. Eventually, there were three millimetre interferometer projects in development. Particularly in Europe, submillimetre astronomy became more important. It turned out once they had made their calculations, what they really wanted to do they couldn’t with the technology available. There’s always competition, but it was clear we had to work together and the idea for ALMA was born. We now have a multilayered organistation funded by the European Southern Observatory (ESO), the National

skyatnightmagazine.com 2013

Institutes of Natural Sciences (NINS) in Japan and the National Science Foundation (NSF) in North America. How will the project be managed? There is a board composed of the funding partners from around the world, the executives who manage the observatory and legal representatives from the funding bodies. It isn’t perfect, because although they all work together at ALMA, they’re working on the different goals of their respective organisations. They have good intentions but an observatory shouldn’t be run like that. Why is this a problem? It is down to how these different organistations are run. You can have a board composed of people who are really good at supervising an observatory, but it is not only the observatory you need to worry about, it is supervising the collaboration. We deal with most of the management responsibilities here in Chile,

but there are also off-site activities run by ESO, the National Radio Astronomy Observatory and the National Astronomical Observatory of Japan. How does ALMA fit in with the other big astronomy projects under construction? When the James Webb Space Telescope is up and running in 2018 it will almost certainly feed ALMA with scientific data and vice versa. When people ask me, “What new project would you like to start now?” I say, “Wait. Right now, we need to get ALMA going to see what it is capable of.” What are your expectations from ALMA? In the next couple of months we’ll have all of ALMA’s 66 antennas up and running but we don’t yet have them operating in the most effective way possible. This will take quite a few years to get right. After that it will be down to the astronomy community to realise ALMA’s true potential.

ALMA JUNE 67

ALMA IMAGE

permanent manmade structure on Earth – is one of the fastest supercomputers in the world, capable of operating at 16 petaflops (16 quadrillion calculations per second). To create an image from the light collected by the individual antennas, the correlator must measure the tiny differences in the time a signal was received by each pair of antennas – and there are over 1,000 combinations of pairs in the main, outlying array alone. By measuring the time differences to an accuracy of one trillionth of a second every millisecond, the correlator is able to gauge the point in the sky the light came from. To produce a complete image, the correlator combines all the data from the main array and the ACA.

ARTIST’S ILLUSTRATION

Þ Gas flows from the disc

of young star HD 142527, indicating that gas giants may be forming around it

All of this information is then sent a few kilometres downhill to astronomers in the control room at ALMA’s base camp, the Operations Support Facility (OSF). From here, the astronomical data is distributed across the world, first to the Chilean capital, Santiago, and then on to North America, Europe and East Asia.

Bright horizons þ The data gathered is sent around the world from the Operations Support Facility at ALMA’s base camp

Although still in the early stages of operations, ALMA is already producing some exciting results. Back in August 2012 astronomers discovered primitive sugar molecules around a distant star with a similar mass to our Sun, showing off the array’s astrobiological applications. The new array has sent back its first observations of forming stars, and in April it was able to locate more than 100 star-forming galaxies in the early Universe in the space of just a few hours. For thousands of years ALMA’s home, the Chajnantor Plateau, has been a site for native Atacameño people to contemplate their place in the heavens – Chajnantor meaning ‘place of flight’ in Kunza, the local language. Now, with the telescope’s initial observations already revealing so much, it looks as though ALMA astronomers will be continuing this tradition for many years to come. S ABOUT THE WRITER Kieron Allen is Sky at Night Magazine’s online editor. He has been working as a science writer since 2011, after completing a postgraduate diploma in journalism.

skyatnightmagazine.com 2013

GREAT ADVANCES IN

astrophotography Emily Winterburn explores 25 defining moments in the history of astrophotography

S

ince the dawn of photography, humankind has tried to capture images of the Universe. Early astrophotography was a huge technical challenge yet today, with just a smartphone, it is relatively easy to get a detailed, crisp picture of the Moon’s surface. Here we look at some of the defining moments in the history of astrophotography, each instigating a revolution in the ways that both amateur and professional astronomers record the wonders of the cosmos. ABOUT THE WRITER

THINKSTOCK X 2, ROYAL ASTRONOMICAL SOCIETY/SCIENCE PHOTO LIBRARY X 2, EDWIN HUBBLES VAR PLATE: COURTESY OF THE OBSERVATORIES OF THE CARNEGIE INSTITUTION FOR SCIENCE, SCIENCE PHOTO LIBRARY, NASA X 2, NASA/JPL, ESO/Y. BELETSKY

Dr Emily Winterburn is curator at the Museum of the History of Science, Technology and Philosophy at Leeds University, and a former curator at the Royal Observatory Greenwich.

 Early deep-sky images

The first photograph of the Moon 

In the early years, not everyone was convinced of the merits of astrophotography and many astronomers still preferred to draw what they saw. Early photography was difficult and its results were unreliable. As these problems were overcome, the next generation of astronomers came of age. Isaac Roberts was among the first astronomers to embrace photography. Roberts was an engineer and businessman, but also an amateur astronomer with his own observatory. He began dabbling in astrophotography in 1883. His technique was to mount his camera onto an equatorially mounted telescope that had a guidescope so the camera could follow the stars during the exposure, which lasted around an hour. The result was a picture containing far more detail than was possible to see with the naked eye.

On 2 January 1839, Louis Daguerre, right, made history by applying photography to astronomy. He took a photograph of the Moon, though the print never survived. Photography was in its infancy and Daguerre was one of its pioneers. His method, called the daguerreotype, was the first to be commercially available.

 Early images of the planets Photography and astronomy joined forces on a large scale in 1874 when stargazers were sent around the world to photograph the transit of Venus. Soon after, observatories began taking their own planetary photographs. Harvard College Observatory was among the first to introduce photographic refractors.

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HISTORY OF ASTROPHOTOGRAPHY JUNE 69

 The blink comparator and Pluto’s discovery

Edwin Hubble’s VAR! plate of M31 

In 1929, Clyde Tombaugh, newly arrived at Lowell Observatory and only 23 years old, was given the task of comparing photographic plates with the aim of finding ‘Planet X’. Planet X was the mathematically predicted planet calculated to be responsible for perturbations in the orbits of Neptune and Uranus. Tombaugh’s job was to systematically go through pairs of photographic plates – two plates of the same area of the sky taken a few days apart – and look for objects that had moved. To help him he had a ‘blink comparator’. This device, a frame with a scale and moveable microscope allows you to switch or ‘blink’ between pictures comparing them section by section. On 18 February 1930, almost a year after he began, Tombaugh found Pluto.

By 1923 photography was part of every observatory’s arsenal and studying photographic plates was usual work for astronomers. On 6 October at Mount Wilson Observatory, Edwin Hubble studied his plates from the night before, and spotted a Cepheid variable star in the Andromeda Galaxy, M31, which showed that it was another galaxy.

 First image of the far side of the Moon Luna 3 was a radio-controlled Soviet spacecraft sent to photograph the far side of the Moon. This was 1959, at the height of the Cold War and resulting Space Race. The photograph was taken on 7 October 1959 and amazed the world with an unprecendented view of our natural satellite.

First images taken by a person on another world  The US Apollo 11 mission famously landed the first men on the Moon on 20 July 1969. Those men, Neil Armstrong and Buzz Aldrin, took a specially designed Hasselblad camera that could be used with a spacesuit. This type of camera was used on several Apollo missions.

 First images from Mars’s surface Viking 1 landed on the surface of Mars in the Chryse Planitia on 20 July 1976, 11 months after leaving Earth. Within seconds of its arrival the lander sent back its first photograph, via its orbiter, a process that took four minutes. The photograph showed a dry, rocky surface. Colour pictures, including the one above, followed the next day.

The ‘Blue Marble’  This iconic image of the Earth from space was taken on 7 December 1972 by astronauts on the Apollo 17 mission. It was the first widely distributed photograph of our planet from space. Some say it changed the way people thought about Earth, inspiring renewed interest in the environmental movement.

Adaptive optics emerge Adaptive optics is a means of overcoming the distortions that appear when viewing stars through Earth’s atmosphere. It uses computercontrolled, deformable mirrors and a bright reference star (or laser beam) to continually correct these aberrations. Scientists at the European Southern Observatory were among the first to perfect adaptive optics in the 1980s.

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The Pillars of Creation  This picture of a portion of the Eagle Nebula was assembled by astronomers Jeff Hester and Paul Scowen at Arizona State University in 1995. It was taken by the Wide Field and Planetary Camera 2 mounted on the Hubble Space Telescope. The image has become one of the most iconic astrophotos of all time.

 Early consumer DSLR cameras Digital single-lens reflex (DSLR) cameras, once the preserve of professional photographers, became affordable to regular consumers about a decade ago. They were quickly adopted by astrophotographers and today are used by countless amateurs around the world due to their versatility and the ease of processing digital astro images.

The rise of RegiStax and the webcam 

NASA/ESA/STSCI/J. HESTER AND P. SCOWEN (ARIZONA STATE UNIVERSITY), CANON, NASA/JPL/SPACE SCIENCE INSTITUTE, PAUL WHITFIELD X 3, DAMIAN PEACH, ITELESCOPES.NET, NASA/JPL-CALTECH/HARVARD-SMITHSONIAN CFA

In 2001 Cor Berrevoets produced RegiStax – a free program that lets you produce images of the Sun, Moon or planets from videos filmed on a webcam or high frame rate camera. This, and similar software, lets amateurs produce remarkable pictures of the Solar System with simple equipment.

Cassini at Saturn The Cassini-Huygens mission launched in 1997. In 2004 it arrived at Saturn and its two parts – the Cassini orbiter and the Huygens probe, bound for Saturnian moon Titan – went their separate ways. The images Cassini has sent back were full of unprecedented detail and gave new information about Saturn and its many moons.

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 Amateur equipment becomes more affordable As professional astronomy became increasingly about big international telescopes and space missions, amateur astronomers saw great changes occurring too. Amateur equipment such as telescope mounts and high-quality CCD cameras became much more affordable, a process helped by the rise in cheap electronics at the start of the 21st century.

HISTORY OF ASTROPHOTOGRAPHY JUNE 71

 The age of the amateur dawns Damian Peach from the UK and Christopher Go from the Philippines are just two amateur astronomers who have made use of the recent developments in amateur astronomy technology. Using everyday equipment they produce planetary images – like this one of Jupiter by Peach – that rival those of professionals a few decades ago.

 Modern multiwavelength astronomy Today’s professional astronomers use a huge range of telescopes, enabling them to observe across the entire electromagnetic spectrum. From infrared space telescopes capable of peering through gas and dust to study hidden star formation, to missions surveying the sky in X-rays, the technology lets us study the cosmos in detail.

 Robotic telescopes come online The idea of remote-access robotic telescopes, available to all, began to emerge in the mid-1990s. One of the first to come into operation was the Faulkes Telescope Project, in 2004, which allows schoolchildren to operate telescopes in Hawaii and Australia. More commercial enterprises followed: the Sierra Stars Observatory Network (SSON), iTelescope.Net (formerly Global Rent-a-Scope, facilities pictured below) in 2007 and LightBuckets in 2008 – where amateurs and professionals can buy remote, internet access to large telescopes under clear skies. These powerful telescopes are operated from a home computer and allow users to produce beautiful images without the need to invest in or set up the imaging apparatus. Since there are telescopes now in various timezones, there isn’t even any need to stay up late.

Modern amateur optics  Amateur astrophotography has improved immensely since its early days, to the extent that today even a modest amateur setup can capture stunning deep-sky images that would surpass professional images of 30-40 years ago. Much of these improvements are due to the highquality, off-the-shelf scopes available nowadays.

 Accessible autoguiders Autoguiders help a mount track the sky over the course of a long exposure. For a long time, most autoguiders had to be connected to a computer to work. Now, however, standalone models like Sky-Watcher’s SynGuider and the LVI SmartGuider allow you to autoguide without one, making the system much more portable.

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72 HISTORY OF ASTROPHOTOGRAPHY JUNE

Tweeting astronauts  In recent years astronauts on the International Space Station have been using Twitter to tweet pictures from their home in orbit. The pictures from astronauts such as Chris Hadfield (@Cmdr_Hadfield), Paolo Nespoli (@astro_paolo) and Don Pettit (@astro_Pettit) have shown Earth and several astronomical phenomena – like comets and aurorae – from a whole new perspective.

Portable tracking mounts appear

IMAGE COURTESY OF THE IMAGE SCIENCE & ANALYSIS LABORATORY, NASA JOHNSON SPACE CENTER, PAUL WHITFIELD, VINCENT WHITEMAN, NASA/JPL-CALTECH/MSSS, RIA NOVOSTI/SCIENCE PHOTO LIBRARY, NASA/ESA/AND THE HUBBLE SM4 ERO TEAM

Electrically driven tracking mounts have been around since the early 20th century. Today, however, they have become much lighter, more compact and easier to use. Highly portable tracking mounts like the AstroTrac, below, and the Vixen Polarie Star Tracker now allow amateurs to pack up, ship out and photograph astronomical phenomena around the world.

Eyes on Mars  Since the early images from the Viking landers, we’ve been treated to countless pictures from Mars’s barren surface. Modern robotic rovers, like the Mars Exploration Rovers Spirit and Opportunity, and the Mars Science Laboratory Curiosity, right, are covered in cameras. While they’re mostly used for navigation and science, the pictures these cameras return are stunning nonetheless.

Smartphone astronomy  While access to dedicated astronomical CCDs has never been greater, there’s also now a trend toward simplicity. As smartphone camera technology has improved it has become possible to use them to snap pictures of the Moon and planets through telescopes, continuing the tradition of afocal astrophotography.

Russian ‘dashcam’ footage of a fireball While the world waited for the much-anticipated near-miss of asteroid 2012 DA14 in February 2013, another asteroid burnt up in the skies above Russia. Luckily, most Russian cars have ‘dashcams’ to protect against insurance fraud. Their footage of the fireball, shared worldwide via social media, made history. S

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Visions of the Universe, the latest exhibition at the National Maritime Museum, shows how humankind has captured images of the heavens over the centuries, from the earliest hand-drawings to photographs taken by the Hubble Space Telescope. The exhibition runs from 7 June to 15 September. Tickets cost £8 for adults and £2.50 for children (15 years old or under). www.rmg.co.uk/visions

ADD A NEW DIMENSION TO YOUR IMAGING With the STAR ANALYSER A high quality spectroscopic grating designed specifically for ease of use with webcams, video and CCD imagers. This simple device makes a perfect introduction to the fascinating world of spectroscopy, revealing the hidden information contained in the light from stars and other objects.

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Free Parking Friendly personal service for ALL your astronomy needs. Celestron, Sky-Watcher, Meade main stockist for Sussex Beginners most welcome! A large range of telescopes and accessories from the world’s leading suppliers. Tel: 01903 247317 • 16 Mulberry Lane, Goring-by-Sea, Worthing, West Sussex

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The Horsehead Nebula is a ‘dark’ nebula – we see it because it blocks light from objects behind it

Unveiling

THE DARK KNIGHT

T

he wonders of space aren’t always discovered by freezing astronomers staring up at the night sky through their telescopes in the early hours of the morning. Take, for example, the Horsehead Nebula; 125 years ago this month, one of the most recognisable and admired objects in space was first identified in the incongruous setting of a bright, sunlit room – and by a woman who, officially at least, wasn’t even a trained astronomer. During the latter half of the 19th century the science of astronomy was progressing in leaps and bounds

thanks to a couple of significant advances: on the one hand, more precise manufacturing techniques were leading to the creation of ever more powerful and reliable telescopes, while on the other photography was becoming an invaluable means of recording astronomical observations. One location where improved optics and photography came together was at Harvard College Observatory in Cambridge, Massachusetts. Early recognition for the observatory’s astrophotography came in 1851 when a photograph of the Moon, taken using its great refractor (at the time, the largest

in North America), won a prize for technical excellence in photography at the Great Exhibition at Crystal Palace in London. However, it was under the leadership of the astronomer and physicist Edward C Pickering (director of the observatory from 1877 until his death in 1919) that Harvard truly gained its worldwide reputation. According to Pamela E Mack, an associate professor in the Department of History at Clemson University in South Carolina, this reputation was founded on Pickering’s “Baconian concept of science”. He had a belief that the best contribution Harvard >

ROBERT GENDLER/SCIENCE PHOTO LIBRARY

Paul F Cockburn tells the story of how one of the most recognisable nebulae in the cosmos was found by accident

Þ The 8-inch Bache astrograph was one of the finest photographic reflectors of the time

Þ The plate that revealed the Horsehead Nebula; Fleming made the discovery in June 1888

Þ Edward Pickering helped open the door for women astronomers, in a limited fashion

HARVARD COLLEGE OBSERVATORY X 3, GETTY,

Þ Fleming, standing, oversees a group of women ‘computers’ as they review astronomical plates > College Observatory could make to

astronomy in general was “to collect as much data as possible”. Arguably, Pickering also had an eye for the ladies, though not in a prurient way. Collecting a lot of astronomical data is one thing, but he recognised the challenge of then processing it. There was a necessity to hire people as ‘computers’ – a term used skyatnightmagazine.com 2013

in the 19th century to describe anyone who carried out repetitive calculations and measurements. Pickering was of the opinion that women were best suited to this task; an unusual stance in the 19th century. Admittedly, the significantly lower salaries given to women must have been an attraction to a financially minded

entrepreneur such as Pickering – whose time at Harvard proved he was adept at persuading wealthy philanthropists to part with their money – but it appears that he genuinely did believe women were better suited in temperament to the painstaking “examining, measuring, and discussing” of astronomical data. And so, in a significant way, Edward opened the door of professional astronomy to women, albeit initially in an interpretive role; in the 19th century, women only collected, catalogued and reviewed data taken by their male peers.

Gender divide Certainly, women were allowed nowhere near the observatory’s precious telescopes, especially its first photographic refractor, the Bache astrograph. Named after the Bache Fund of the American National Academy of Sciences, which had funded its

THE HORSEHEAD NEBULA JUNE 77

purchase in 1885, this significant telescope had an 8-inch aperture and a 44.8-inch focal length, which was refigured before installation to 48.8-inches to ensure that the scale of its photographic plates would be the same as existing star charts. These somewhat delicate plates would continue to be used during the astrograph’s subsequent long working life in Peru and South Africa. For many years the advantage of using plates, compared with film, was the extremely low risk of image distortion, especially when taking wide-field images. However, the principal downside remained the considerable amount of preparation the plates required in the laboratory prior to being used on the telescope, along with the near-impossibility of creating even two plates that would react identically during a long exposure. The only alternative, film, was never seriously adopted by professional astronomers; it would be almost a century before the development of specialist astronomical CCD cameras would lead

to the replacement of photographic plates in professional observatories from the mid-1990s.

Pickering’s harem Pickering’s belief in women’s abilities was particularly important in 1886, when significant new funding from the widow of a keen amateur astronomer, a Dr Henry Draper of New York, allowed him to set up the Draper Memorial, a large-scale project to classify the spectra of thousands of stars.

new empirical classification system to classify stars. When the first edition of the Draper Catalogue was published in 1918, Mina – who had died seven years earlier – had herself classified 10,498 stars. Contemporary accounts make clear that the women involved in this process of detailed examination also noted down any other objects of interest found on the photographic plates. As a result, Fleming discovered numerous novae, variable stars and nebulae during her many years at Harvard College Observatory – including, of course, the Horsehead Nebula. The photographic plate on which the Horsehead Nebula was first noted is listed as number B2312, taken using the Bache astrograph by Edward’s brother William Henry Pickering on 6 February 1888. However, it would be the best part of five months before that plate was actually examined in the ‘computers’ workroom, placed on a wooden frame set an angle of 45º and illuminated by natural sunlight reflected up from a horizontal mirror underneath. >

“Fleming discovered numerous novae, variable stars and nebulae during her years at Harvard” As work on the Draper Memorial progressed, the number of women working at Harvard College Observatory – nicknamed ‘Pickering’s Harem’ by his peers – increased significantly, numbering 19 by 1900. Edward soon assigned his chief assistant, Dundee-born Mina Fleming, the task of studying the spectra on the plates and developing a

MINA FLEMING COMPUTER TO CURATOR

Williamina Paton Stevens Fleming, born 15 May 1857, was the eldest daughter of prosperous Dundee craftsman Robert Stevens. ‘Mina’ (as she was generally known) was a schoolteacher until she married James Orr Fleming in 1877. The couple emigrated to Boston the following year, but the marriage did not last; a pregnant Mina was left abandoned and forced to find work as a housekeeper in

the home of Edward C Pickering, the director of Harvard College Observatory. Pickering was apparently impressed by Mina’s education, personality and attention to detail, but his claim of how “his Scotch maid” could do better than his incompetent male assistants is almost certainly a myth. Nevertheless, Mina was hired by Harvard in 1881, Pickering describing her duties as “at first of the simplest character, copying and ordinary computing”. A few years later, however, he was convinced she would “satisfactorily” assist him in a major project to categorise the prism spectra of hundreds of thousands of stars. In time, Mina not only supervised the other women ‘computers’ at the observatory but, as its curator of astronomical photographs, would help Pickering develop a system to classify the stars based on the spectrum of their light. She also discovered 222 new variable stars, 94 ‘superluminous’ heliumdominated Wolf-Rayet stars and several other astronomical objects – including the Horsehead Nebula. When she died in 1911, her reputation ensured she was an honorary member of the Royal Astronomical Society and a member of both the Astronomical and Astrophysical Society of America and the Société Astronomique de France.

Through published essays and a lecture given at the 1893 Congress of Astronomy and Astrophysics in Chicago, Mina also helped open up astronomy to women, although she was nevertheless frustrated by the significant disparity in pay between the sexes. “Does (Pickering) ever think that I have a home to keep and a family to take care of as well as the men?” she wrote in her journal in March 1900. “But I suppose a woman has no claim to such comforts. And this is considered an enlightened age!”

Þ A plaque dedicated to Mina Fleming was mounted at the University of Dundee in 2008 skyatnightmagazine.com 2013

This stunning infrared Hubble image reveals delicate gas structures in the Horsehead Nebula usually masked by dust

NASA/ESA AND THE HUBBLE HERITAGE TEAM (AURA/STSCI), RON BRASHEAR/CURATOR OF HISTORICAL PHOTOGRAPHSOBSERVATORIES OF THE CARNEGIE INSTITUTION, HALE OBSERVATORIES/SCIENCE PHOTO LIBRARY, MARTIN PUGH X 2

INSIDE THE HORSEHEAD NEBULA “Despite being such a familiar object, the Horsehead Nebula has always retained an air of mystery,” says Marek Kukula, public astronomer at the Royal Observatory Greenwich. “As an object that was only discovered with the advent of astronomical photography it is fitting that, even today, the nebula is only giving up its secrets to specialised imaging technology.” While massive clouds of dust and gas help make the nebula the beautiful object we see, they are also extremely effective at blocking light. Since the early 20th century, however, astronomers have increasingly got round this problem by moving beyond the visible

spectrum, focusing on wavelengths of electromagnetic radiation that are not blocked by the nebula’s dust, such as infrared. All celestial objects emit some infrared radiation and the wavelength at which they radiate most intensely will depend on their temperatures. This means that some infrared wavelengths are better suited for studying certain objects than others. Astronomers usually divide infrared into three spectral regions: near-, mid- and far-infrared, although the specific boundaries between these bands can and do vary. Nearinfrared observations can be made from ground-based observatories such as the

VISTA telescope at Paranal in Chile, however, mid- and far-infrared observations have only really become possible with the launch of space telescopes such as Spitzer and Hubble, which can take images well above our moist, infrared-absorbing atmosphere. It is fair to say that the results have generally been astounding; viewed in infrared, the obscuring dust and gas can be been ‘stripped away’ to reveal numerous bright, newborn stars. “Infrared cameras at last allow us to see what’s going on behind the Horsehead’s veils of dust,” explains Marek. “As a result, astronomers are gaining new insights into the formation of low-mass stars.”

> Photographic plate B2312 was one of seven Fleming examined on 27 June 1888. In her records she noted: “A large nebulosity extending nearly south from Zeta Orionis for about 60 minutes. More intense and well marked on the following side, with a semicircular indentation five minutes in diameter 30 minutes south of Zeta. Good plates of this region show this object, and it has been used here as a test for some time.” That “semicircular indentation five minutes in diameter” is, of course, the feature that we now think of as the Horsehead Nebula.

moon, Phoebe, in 1899, while, at the time of her death from pneumonia in 1911, Fleming was internationally recognised for her work classifying stellar spectra. For decades neither were linked to the discovery. This is almost certainly down to a listing published in John Dreyer’s Index Catalogue of 1895, which credited the discovery of IC 434 (and other nebulae) to simply “Pickering”. Assumed to be Edward given his role as director of Harvard College Observatory, this ‘fact’ was repeated for many years, even though Harvard’s own archives clearly showed otherwise. Edward’s own Nebulae discovered at the Harvard College Observatory, published in the Annals of Harvard College Observatory, clearly credits the discovery to Fleming. In the decades that followed, other pioneering astrophotographers, such as America’s Edward Emerson Barnard (18571923), Germany’s Max Wolf (1863-1932) and Wales’s Isaac Roberts (1829-1904) turned their attentions to the same region of space. Arguably though, it was the American John Duncan (1882-1967), using the powerful, 100-inch Hooker

telescope at Mount Wilson Observatory in California in 1920, who produced the first detailed image of the nebula – even turning the image sideways to make the resemblance to the ‘knight’ chesspiece more obvious. John’s subsequent reference to it as the Horsehead Nebula in his 1926 book of space photography may even be the first published use of its colloquial name. For professional astronomers, the development of infrared observation since the 1980s has enabled the Horsehead Nebula to be examined in greater detail, revealing previously unseen stellar nurseries and providing evidence of the constituent elements of this most beautiful of celestial objects. Yet improved photographic observations in even the visual spectrum have contributed to something else: a public popularity no doubt based on the aptness of its colloquial name. When, back in 2001, some 5,000 people were asked to choose a subject for observation to mark the 11th birthday of the Hubble Space Telescope, it was no real surprise that the clear winner of the online vote was the Horsehead Nebula.

A true dark horse Surprising as it may sound now, Fleming’s discovery hardly rocked the astronomical community. In part, this was down to her describing it as merely a detail of a larger object, nebula number 434 – it would not be listed separately for several years. For the most part, though, faint nebulae were simply not of particular interest to most astronomers at the time. William Pickering, who actually exposed the photographic plate, remains best known now for detecting Saturn’s ninth skyatnightmagazine.com 2013

THE HORSEHEAD NEBULA JUNE 79

In 1920, John Duncan used the 100-inch Hooker telescope, left, to take the first detailed picture of the Horsehead Nebula, shown above

cameras ensuring that, with some perseverance, skill and luck, it is perfectly possible for anyone to capture an image that would doubtless have impressed both Edward Pickering and Mina Fleming. S While amateur – and even many professional – astronomers can’t hope to replicate the quality and detail of images now possible courtesy of the Hubble Space Telescope, the past 40 years have arguably seen an even more significant revolution in astrophotography. As early as the 1980s, new kinds of film

were reducing exposure times, allowing members of the public to produce astro images surpassing in detail those from the biggest telescopes of less than a century before. The past decade, of course, has seen the rapid rise of digital photography, with the general availability of CCD imagers and sensitive DSLR

ABOUT THE WRITER Paul F Cockburn is a journalist who specialises in popular science; his favourite course while at university was – naturally – history of science.

THE EXPERT Martin Pugh won the Astronomy Photographer of the Year competition in 2009 with an image of the Horsehead Nebula. He shares his tips for capturing this enigmatic object SBIG STL11000M CCD camera, with Astrodon colour filters.

What is it about the Horsehead Nebula that appeals to you? From an aesthetic point of view, there is so much going on in the field; the Horsehead itself, the ‘curtain’ behind the Horsehead and NGC 2023, the nearby blue reflection nebula. The range of colours is quite amazing. What I find most interesting is how the Horsehead and Flame Nebulae both appear to cling to the bright star Alnitak. I would love to know why! What equipment did you use to take your winning photograph? I used a 12.5-inch RCOS Ritchey-Chretien telescope mounted on a Software Bisque Paramount ME mount. The camera was an

What would you say is the minimum equipment you need in order to photograph the Horsehead Nebula? The Horsehead is a dim object, so you could not expect to get any decent results from exposures that are just a few seconds long. Also, to get high resolution data, you need a telescope with a long focal length, which places demands on all aspects of your equipment. Overcoming these demands usually means high cost. However, I would suggest that the minimum equipment would be a short focal length refractor, a reasonably good quality equatorial mount and you could probably get decent data with the Canon EOS 60Da DSLR camera, which has been modified for astrophotography. As an alternative to a DSLR, a cooled, one shot colour CCD camera would be an excellent choice. If you want to go a little more upmarket from that, try a fast astrograph such as the AG10 by Orion Optics. These very fast telescopes, coupled with a CCD camera or DSLR, will produce some great data. It is all down to budget at the end of the day.

What are the main photographic challenges posed by this object? The Horsehead is a dark nebula, so achieving a nicely defined outline of it should be the goal. Many images suffer from reflections and stray light caused by the very bright star Alnitak. With exposure time, it all depends on equipment: if you have a ‘fast’ telescope and you ‘bin’ your CCD camera 2x2 or 3x3 (allowing adjacent pixels on the sensor to be combined) – which increases sensitivity fouror nine-fold respectively – then you are going to get good results quickly. However, binning the camera, while increasing sensitivity, reduces the resolution.

Martin’s winning image of the Horsehead Nebula from 2009

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Skills

Brush up your practical astronomy prowess with our team of experts

Contents The guide

How to

Sketching

Scope doctor Lost in space

80

82

85

86

Introducing the deepsky catalogues

SKILLS

Project the Sun safely with a homemade solar funnel

Learn how to draw asteroid 6 Hebe

Steve Richards answers your astro equipment queries

87

Keith looks back with shame at his observing logbook

The guide

Deep-sky catalogues

Beyond Messier and NGC, dozens more catalogues await But it wasn’t until the invention of the telescope that the previously invisible deep-sky objects appeared – and with them the first deep-sky catalogues. This is not to say that no deep-sky objects were known before this time; it’s just the ones that had been found were considered to be fuzzy stars or small ‘clouds’, such as the Andromeda Galaxy. However, it was not the telescope that uncovered the true nature of deep-sky objects, but the scientific progress that followed. The Andromeda Galaxy, designated M31 in the the Messier Catalogue, was still thought to be a nebula after nearly 200 years of telescope observations. It wasn’t until the 1920s that Edwin Hubble proved that it is an independent spiral galaxy that exists outside the Milky Way.

Enduring popularity THINKSTOCK, GERARD LODRIGUSS/SCIENCE PHOTO LIBRARY

BILL SCHOENING/VANESSA HARVEY/REU PROGRAM/NOAO/AURA/NSF, WILL GATER X 2,

With Anton Vamplew

M31 was labelled as a nebula in the NGC catalogue; it wasn’t until the 1920s that we knew better

T

he Messier and NGC catalogues are undoubtedly the most famous references for deep-sky objects. But despite their brilliance as sources of what you can see in the night sky, they are just the tip of the iceberg – there are dozens of other catalogues and many skyatnightmagazine.com 2013

more fascinating sights that aren’t mentioned within them. The idea of listing what can be seen in the night sky didn’t begin with Messier; it started well over 3,000 years ago, when Sumerian and Babylonian astronomers started recording stars and constellations.

The Messier Catalogue remains popular among amateur observers because the objects in it are fairly bright and easily visible through small telescopes. The catalogue contains 110 entries – all 103 from the original 1781 catalogue and an additional seven added between 1921 and 1967. The list was extended based on notes found in the original 18th century observations of Messier’s assistant, Pierre François Méchain. In fact, around a quarter of the Messier objects were discovered by Méchain – although if they

SKILLS JUNE 81

EXPLORING THE CATALOGUES There are so many deep-sky catalogues that it is impossible to list them all, but these four all contain objects that can be seen by amateur astronomers

Melotte

245 ENTRIES

Catalogues Open and globular clusters Created by Philibert Jacques Melotte in 1915, based on photographs taken by British astronomer John Franklin-Adams and published posthumously a year earlier. Most famous object Melotte 111 in Coma Berenices. See it in early June at 23:00 BST, high in the southwest, using binoculars.

Abell

4,073 ENTRIES

Catalogues Galaxy clusters Created by Created by George Abell in 1958. The original version was based on the Palomar Observatory Sky Survey and listed 2,712 objects. A further 1,361 were added in 1989, after Abell’s death. Most famous object A1656 in Coma Berenices. See it in early June at 23:00 BST, high in the southwest, using a large telescope.

knew what the catalogue was being used for today they might be a little surprised. The two Frenchmen were comet hunters, and both comets and these deep-sky objects appeared as fuzzy blobs in the telescopes of the time. They hatched a plan; they would make a list of the annoying, ever-present nebulae and other objects, a catalogue of things to avoid while comet hunting. The irony is that their magnum opus is now considered to be the definitive collection of deep-sky objects not to be missed. The Messier objects are dotted randomly over the night sky, but the other well-known list is much more systematic in its approach. The New General Catalogue of Nebulae and Clusters of Stars (NGC),

Collinder

471 ENTRIES

Barnard

370 ENTRIES

Catalogues Open star clusters Created by Swedish astronomy graduate Per Collinder in 1931 as an appendix to his dissertation. Most famous object Collinder 399 in Vulpecula, also known as Brocchi’s Cluster or the Coathanger. See it at the end of July at 23:00 BST, high in the south, using binoculars.

Catalogues Dark nebulae Created by The work of Edward Emerson Barnard, published after his death in 1923. The catalogue was extracted from his Photographic Atlas of Selected Regions of the Milky Way. Most famous object B142 and B143, ‘Barnard’s E’ Nebula in Aquila. See it at the end of July at 23:00 BST, in the south, using binoculars.

compiled in 1888 by John Dreyer, works around the sky in order of each object’s right ascension. It is also much larger than the Messier Catalogue, with 7,850 entries. This was also extended by the two-part Index Catalogue of Nebulae and Clusters of Stars (IC), which added a further 5,386 objects. Together, they form the most comprehensive list of visible deep-sky objects. How could Messier and Méchain miss so much? By the time Dreyer created his catalogues the standard of telescopes had improved and their size had increased substantially. That, in turn means that today’s amateur astronomers need much larger scopes to explore many of the NGC and IC objects.

Improved technology and scientific methods has led to new catalogues, many of which focus on one specific class on night-sky object – star clusters, X-ray and radio sources and emission nebulae among them. Some are the result of surveys made by professional observatories – several are derived from the Palomar Observatory Sky Survey – others are the efforts of impassioned individuals who, like Messier, were single-minded in their observations. There are even a few created specifically for amateur use, including the Herschel 400 and Patrick Moore’s own Caldwell Catalogue; both useful bridges to jump from the 110 objects of the Messier Catalogue to the near 8,000 of the NGC. S skyatnightmagazine.com 2013

82

SKILLS WARNING

How to

Do not look directly at the Sun with the naked eye or any unfiltered optical instruments

build a solar funnel With Mark Parrish

This easy-to-make device lets you view the Sun in safety

TOOLS AND MATERIALS

CARDBOARD AND TRACING PAPER

Three pieces of thin, A4 packaging card for the funnel. Tracing paper works really well for the screen although any translucent, thin material is worth trying. Long summer evenings and a solar funnel make an ideal combination for viewing the Sun

ALL PICTURES:MARK PARRISH

W

ith the days at their longest, now is a great time to indulge in a bit of solar observing. But you can’t simply point your telescope at the Sun – without an appropriate filter or a projecting device attached, you’ll almost certainly lose your eyesight. Last month we explained how to build a white light filter to cut out the Sun’s harmful rays. This month we’re showing you how to make an alternative but equally effective accessory for use with a refractor, called a solar funnel. Our solar funnel is simply a hollow cone with an eyepiece fitted in the narrow end and a translucent screen at the other. It uses a projection technique to disperse sunlight over a wide area and onto the screen. Because the eyepiece is internal, there is no way for you to accidentally look into the light path. Although this is a safe technique, it is important that equipment is never left unattended, especially when children are around. skyatnightmagazine.com 2013

The length of the cone is calculated to suit small refracting telescopes with a focal length between 300mm and 1,000mm. Because the aperture of such telescopes will be relatively small and they lack internal structures, heat build-up is not a problem. However, if your scope’s main lens is larger than 3 inches we recommend reducing the effective aperture by using a cardboard mask with a smaller hole (2 inches) cut in the centre and taped over the dew shield. Solar funnels are less suitable for use with Newtonian reflectors as these telescopes have large apertures and the secondary mirror can be damaged by heat.

Funnelling the Sun Like last month’s filter, the solar funnel displays the Sun in white light – in other words, all the visible wavelengths of light are seen. The eyepiece determines the size of the image; we found that any eyepiece with a focal length between 12mm and 25mm produces acceptable results, so you

EYEPIECE

Any low-cost eyepiece with a focal length in the 15-25mm range will suffice. FINISH

For a non-reflecting internal finish matt black spray paint works well. For the outside, you could use gloss paint or sticky-backed plastic. TOOLS AND SUNDRIES

Craft knife, steel ruler, hot-melt glue gun or strong craft glue, spray adhesive or glue stick, black duct tape or electrical tape, strong elastic bands.

may be lucky enough to have a suitable candidate in your accessory box already. Using a solar funnel is straightforward. After capping your main lens and any accessories – such as finderscopes – and with your eyepiece fitted, position it in the focuser. Ensure the eyepiece is firmly fixed in the funnel and gripped in the focuser. Next, align the telescope with the Sun – the easiest way is to watch the shadow the telescope tube casts on the ground. Line up the scope so the shadow becomes

SKILLS JUNE 83

STEP-BY-STEP GUIDE

A solar funnel can reveal sunspot groups – one is visible at the top right of the solar disc here

small and round. When it is, you should be pointing towards the Sun. Remove the lens cap (or uncover the opening of your aperture reducer, if you fitted one) and you should see a bright image of our star somewhere on your screen. Finally, make small adjustments to the mount and focuser to centralise the image and bring out any fine details on the Sun’s surface. All being well, you should be treated to a display of sunspots, which appear dark against the bright surface. You could sketch these and keep a record or (as we did) photograph the screen using a camera or smartphone. If you’re feeling ambitious you could draw a circle on your tracing paper screen in advance and then mark sunspot positions in-situ with a felt-tipped pen. Replace this screen after each viewing session and keep them as a record of your observations. You should also be able to see variations in tone across the solar surface. A nice paint finish or sticky-backed plastic covering would increase the solar funnel’s longevity; the logo is, of course, optional. Whatever you choose to do, we know you’ll get a lot of pleasure from making and using this simple device. S

Once the solar funnel is securely attached to your telescope, you are ready to start observing

STEP 1

STEP 2

STEP 3

STEP 4

STEP 5

STEP 6

Print out two copies of the funnel template and one copy of the back screen panel. (Templates for both parts can be found on this month’s coverdisc.) Stick the templates to the A4 card using spray adhesive or a glue stick.

Use a hot-melt glue gun (or strong glue) to bond the four sides of the funnel together and make up the back screen frame. Use tape to temporarily hold the parts together if you’re using traditional glue. Don’t glue the four ‘jaws’ at the bottom of the funnel together.

Cut a square of tracing paper and tape or glue it across the inside of the opening of the back screen frame. Glue the back panel into the end of the funnel to attach it permanently or tape it if you think you’ll want to change the screen occasionally.

Using a steel ruler to keep the lines straight, carefully cut out the four sides of the funnel and the back screen panel. Score or partly cut the dotted lines where the card will be folded. The templates can be gently peeled off or left in place.

Before fixing the tracing paper, give the inside of the funnel and the whole back screen frame a generous coat of matt black spray paint. You could also cover the joints using black tape to keep out stray light and neaten things up.

Remove your eyepiece’s rubber eye-shield and push it between the four ‘jaws’ at the bottom of the funnel. Wrap strong elastic bands around the ‘jaws’ to hold the eyepiece in place. Apply additional tape to hold it securely.

skyatnightmagazine.com 2013

SKILLS JUNE 85

SKILLS

Sketching 6 Hebe

With Carol Lakomiak

NEED TO KNOW STEP 1 Place Hebe on the eastern edge of your eyepiece’s field of view. Using a B pencil, draw the asteroid and the brightest stars in the field. Look for any geometric shapes formed by the stars and use them to help you draw the positions of the stars as accurately as you can.

NAME: 6 Hebe TYPE OF OBJECT: Asteroid CONSTELLATION: Serpens Caput RA: 16h 10m 43s to 16h 06m 53s

June 1st 11pm UT

DEC.: 01° 36’ 56” to 01° 35’ 48” TIME TO SKETCH: 1-5 June, 11pm UT till 1am UT

Same night Two hours later

June 2nd 11pm UT

June 3rd 11pm UT

June 4th 11pm UT

June 5th 11pm UT

EQUIPMENT: 3-inch refractor or larger; B pencil FIELD OF VIEW: 60 arcminutes; 80x magnification

ALL PICTURES: CAROL LAKOMIAK

T

he first four asteroids – Ceres, Pallas, Juno and Vesta – were discovered between 1801 and 1807. Since astronomers of the time believed there were only four of these objects, they abandoned their search after the discovery of Vesta. However, the search was resumed in 1830 by a German amateur named Karl Ludwig Hencke. His efforts were rewarded by the discovery of a fifth asteroid, Astraea, on 8 December 1845. A sixth, Hebe, followed on 1 July 1847 and it is this object – and its path across the sky – that we’ll be sketching this month. Since asteroids are constantly moving, you’ll need to locate Hebe in order to sketch and track it. To find it on the first suggested sketching night, centre mag. +3.9 Marfik (Lambda (l) Ophiuchi) in an eyepiece that shows 1° of sky – then star hop five eyepiece-widths westward. Mag. +9.6 Hebe will be in the bottom fifth of the field of view, just east of the mag. +6.6 star known as SAO 121403 (or HD 145316). Adjust your telescope to bring Hebe into the centre of the field and then readjust it so Hebe is just inside the

eastern edge. You’ll only need to sketch the star field once, because during the suggested sketching nights Hebe will be travelling westward through it. Hebe’s movement will be noticeable during the suggested two-hour window every night. If you are able to observe for the entire period, mark its position at the beginning and the end of your observing session. To relocate Hebe’s star field during the subsequent nights, begin at Marfik again and follow the same star-hopping directions. The star field you sketched on the first night will be the same as what’s in your eyepiece – the only differences will be Hebe’s new location and an empty spot where the asteroid was the night before. Determine its new location and draw it in the star field – then add the time and date. It’s quite rewarding when you begin to see how far the asteroid actually moves in 24 hours. At the end of the suggested sketching period, finish off your sketch by transferring it to a computer and using a photo editing program to invert it to a negative image.

STEP 2 When populating the star field, remember to draw the fainter stars smaller than the brighter ones you drew in Step 1. You’ll be able to detect Hebe’s movement during the two-hour viewing period – mark its position at the beginning and end of the session.

STEP 3 The recommended 1° field of view is wide enough to track Hebe throughout the suggested sketching nights. Bring your sketch on each night and centre your eyepiece on the starfield. Hebe will move westward: draw it, and add the date and time.

skyatnightmagazine.com 2013

86

SKILLS

SCOPE

doctor

Our resident equipment specialist Steve Richards cures your optical ailments

I can’t bend down to look through my mount’s polarscope. Can I still use it to polar align with a mirror or CCD camera? RON PASHLEY

Using a polarscope can be extremely uncomfortable as it usually involves kneeling down to look through it at a rather awkward angle. From there, you have to look upwards at the same angle as your latitude. The combination of these two contortions certainly limits the time most of us can spend making this important mount calibration. Because of the eye relief of the polarscope, a mirror wouldn’t work well as other parts of the mount would intrude, making it difficult to align your eye. A compact digital camera with a ‘live view’ function could be pressed into service to make viewing a little easier, but this would still be in the same plane as your eye so wouldn’t

STEVE RICHARDS X 2

An adapted webcam reduces the amount of contortions needed to use a polarscope

achieve the desired result. However, using a webcam and a small laptop would be a great way of resolving the issue. Plus having a PC outside would also provide other advantages, such as giving you access to planetarium software and even computer control for your mount. You can adapt a webcam by attaching a 32mm push-fit waste access plug, available from DIY stores, to the lens barrel of the webcam via a hole filed out of the plug’s base. This adaptor can then be pushed onto the polarscope’s eyepiece. Alternatively you could do what we’ve done and modify an old eyepiece holder as shown in the picture below.

With Steve Richards Our Scope Doctor and all-round gear guru is a keen amateur astronomer and astrophotographer. He loves nothing more than tinkering with telescopes and accessories.

STEVE’S TOP TIP cope base

How can I make my Dobsonian teles move more smoothly? n pads and Dobsonian mounts usually employ Teflo of the tion Formica bearing surfaces to allow rota enough just with de, telescope in azimuth and altitu too often All tion. posi in cope friction to hold the teles h stiction muc too from r suffe can ing the azimuth bear ements. mov jerky (static friction), leading to unwanted m syste ing bear ballInstalling a ‘Lazy Susan’ steel e Thes . rade upg ular pop a in the azimuth axis is discs separated bearings comprise two pressed steel in sizes by steel ball bearings and are available Bearings ly Simp up to 12-inches in diameter from and Bearing King.

Where can I get hold of material to make a solar filter? PATRICK GREEN

Observing and imaging the Sun must be done very carefully to ensure that no damaging radiation can reach your eye or camera, causing immediate and permanent damage. A filter that fits to the front of your telescope, pictured right, is the safest way of achieving this. Baader Planetarium produces a film for making solar filters called AstroSolar Safety Film. It’s available in A4 sheets that can be cut to size to produce a safe filter by following the comprehensive instructions included in the pack. The film has an optical density of five, which reduces the intensity of sunlight by 99.999 per cent without imparting any colour cast to the view. It can be bought from retailers including The Widescreen Centre, Telescope House and Astronomia. Thousand Oaks Optical in the US also produce solar filter material, which can be ordered through its website.

Email your queries to [email protected] skyatnightmagazine.com 2013

SKILLS JUNE 87

SKILLS

LOST IN

With Keith Hopcroft

The trials and tribulations of a novice astronomer

I

near hysterical sense of excitement. “Saturn and its rings are stunning!” I wrote, followed, a month later, by “Fantastic first ever view of Jupiter!!

’m poised over my tattered and battered astronomy logbook with some restorative sticky tape, when I’m struck by an obvious question. Not, ‘Why is my logbook in such a shocking state?’, because that I can explain: it is the combined effects of being dropped, exposed to wind and dew, stood upon and, on one memorable occasion, chucked at next door’s dog in a counterproductive attempt to stop it barking. No. The question is, why do I keep a logbook at all? What’s it for? A quick flick through reveals that the early entries have a kind of naive charm. Here’s the very first: “Binoculars gave a good view of Orion and Pleiades. Next time find Cancer – Saturn is in there somewhere.” A few entries later, I’ve got my first telescope and my notes develop a

Soon afterwards, though, there are signs of cynicism creeping in, with gripes about dew, moonshine, slew limits and my neighbour’s security lights. Ominously, the exclamation marks have disappeared, too. Subsequent entries would perplex nonastronomers. Thus, “Unimpressed by M1” and “Unsuccessful hunt for Coathanger.” The logbook increasingly becomes an official record of disaster, too, including, “Severely hampered by power cable snapping” and “Nightmare: no battery in finderscope” But among those troughs are many peaks. Such as, “Comet P Homes, amazing!” [that’ll be Comet 17/P Holmes – Ed], “Stupendous view of Saturn with rings edge-on, like a small cherry pierced by a cocktail stick” and, of course, “Eclipse of Moon. Amazing copper colour with previously washed out stars around it, incredible!!!” Note the return of the exclamation marks. So, did I repair my logbook? Of course I did. Quite apart from reminding me that I don’t need to worry about finding seasonal ‘must see’ lists – the log has a ready supply – it reminded me why I do astronomy. Because I love it, and, being a conscientious objector to astrophotography, this is the only record I have. Never again will I chuck my beloved logbook at the neighbour’s dog. A brick, maybe.

And its moons!!!” Clearly, by this stage, exclamation marks have become an indicator of astronomical ecstasy. After a year or so, there’s the first note of debauchery, with “Utterly glorious night post barbecue...” (that’ll be the alcohol talking), “...couldn’t be bothered with scope...” (told you) “...but saw Jupiter and Summer Triangle with binoculars. Wow!!” Frankly, I’m impressed I managed to hold the binoculars the right way round.

Keith Hopcroft is a GP and a national newspaper columnist

skyatnightmagazine.com 2013

WILL HOPCROFT, ILLUSTRATION BY JEFF PARKER

“Being a conscientious objector to astrophotography, this is the only record I have”

Astronomy

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REVIEWS JUNE 89

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

94

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

We find out how Orion has made this man-sized Dobsonian portable

This month’s reviews First light

90

iOptron SkyTracker camera mount with polarscope

94

Orion SkyQuest XX16g Dobsonian telescope

98

Mesumount 200 with Go-To hand controller

Books

102

We rate four of the latest astronomy titles

Gear PAUL WHITFIELD X 4

104

Including this 1.25inch Hyperflex-7E2 zoom eyepiece

Find out more about how we review equipment at www.skyatnightmagazine.com/scoring-categories skyatnightmagazine.com 2013

90

FIRST light

CAMERA, BALL HEAD AND TRIPOD NOT INCLUDED

iOptron SkyTracker

camera mount A lightweight tracking camera mount that has been designed with travel in mind WORDS: PAUL MONEY

PAUL WHITFIELD X 3, PAUL MONEY X 2

VITAL STATS • Price £349.99 • Load capacity 3kg • Latitude adjustment 0º to 70º • Tracking rates Sidereal, half sidereal • Polarscope Illuminated polarscope with 6º field of view • Power requirements Four AA batteries or external DC 9V-12V, 500mA power supply • Extras Padded case • Weight 1.1kg • Supplier Altair Astro • www.altairastro.com • Tel 01263 731505

C

apturing tracked, wide-field images of the night sky with a DSLR camera is very rewarding, especially if you manage to record the grandeur of the Milky Way. The latest tracking mount from iOptron, the SkyTracker, will help you to do this. It is fitted with an illuminated polarscope for accurate polar alignment, a latitude adjustment knob with a graduated latitude scale and an integrated compass and spirit level. It also comes with a padded carry case. The mount can be powered by four AA batteries (not included), which can give up to 24 hours of use depending upon operating circumstances. Alternatively, there is also a power connector for a separate power source, so a portable power tank can be used in the field. Near to the connector is the on-off switch and two further switches, one for selecting northern or southern hemisphere and the other for 1x or 0.5x sidereal rate, sidereal rate being the speed at which the stars appear to move across the sky. We were also supplied an optional iOptron SkyTracker DSLR ball head for the purposes of this review. The SkyTracker is attached to a tripod via a standard 3/8-16 threaded socket; if your tripod has a 1/4-20 screw you will need to purchase an adaptor. We then attached the DSLR ball head and to that

we attached our camera. The mounting block has a reversible 3/8-16 and 1/4-20 screw so you can attach your chosen ball head regardless of its screw thread. The SkyTracker can hold up to 3kg in photographic equipment; it was easily able to hold our Canon EOS 50D and a heavy 70-300mm lens, as well as our lighter 18-55mm lens for wide-field imaging.

Alignment adventures We found the integrated compass useful to roughly find north. Although there is a basic sight hole for rough polar alignment, the illuminated polarscope improved tracking by allowing us to more accurately line up with Polaris. You can improve alignment further with another optional extra, iOptron’s iPhone and iPad polar alignment app, which tells you where to position Polaris in the polarscope for your latitude, time and date; note that the app isn’t compatible with other smartphones or tablets. The in-built compass also has an integrated spirit level, which we found did a poor job – the bubble >

LIGHTWEIGHT PORTABILITY The SkyTracker has an incredibly small footprint and is a lightweight package for getting tracked DSLR images of the night sky. Its dimensions are only 153x104x58mm, which includes the camera mounting block but not the polarscope. It all fits neatly into the supplied padded case, which has a compartment for the polarscope, keeping everything together. At just 1.1kg, the SkyTracker can easily go in hand luggage so is perfect for taking away on holiday and you don’t have to miss out on doing

skyatnightmagazine.com 2013

astronomy if you can’t take a telescope. It may be lightweight, but its robust construction makes for a solid tracking platform and its latitude range of 0º to 70º means its is suitable for astro getaways across a large portion of the world. Since it can be battery powered there is little reason why you can’t capture the beauty of the night sky from anywhere. Just remember to have a set of spares if you are likely to get carried away while imaging.

FIRST LIGHT JUNE 91

< Two 60-second exposures of the Beehive Cluster in Cancer; the left image is untracked, while the one on the right was taken with the SkyTracker on

SKY SAYS… We targeted the bright star Regulus in Leo and took a 30-second exposure with no tracking errors

POLARSCOPE/SIGHT CAMERA MOUNTING BLOCK The camera mounting block can be easily detached from the main unit. It has a reversible screw, meaning that you can use either 3/8-16 or 1/4-20 screw thread ball-and-socket heads.

Polar alignment is important and the SkyTracker takes care of this firstly with a basic sight hole for rough alignment, then with an illuminated polarscope. The reticule of the polarscope can be used for both northern and southern hemispheres.

LATITUDE ADJUSTMENT The latitude adjustment is of sturdy construction and has a worm wheel segment, allowing for fine control. Once the latitude is set it can be locked in place to prevent slippage and misalignment.

skyatnightmagazine.com 2013

92 FIRST LIGHT JUNE

FIRST light > could not reach the central part of the dome

due to the spindle of the in-built compass. Instead we used a small spirit level on the top to ensure the system was level before adjusting the latitude knob for our location. Once set up with our camera and wide-angle lens attached, we were able to take five minute exposures without tracking errors using the 18mm lens. We were also able to get good results with pinpoint stars when we switched to our 70-300mm lens and set it to 300mm. With our Canon EOS 50D and its APS-C sensor, this actually equates to a 480mm lens. We targeted the bright star Regulus in Leo and took a 30-second exposure with no tracking errors. Bear in mind an untracked image normally shows star trails at exposures just longer than 1 second, so this is a vast improvement and allows you to image the brighter deep-sky targets – especially if you stack multiple exposures. There were a couple of considerations to take into account. When the camera was on the eastern side

of the mount it tracked better than when it was on the western side, where the weight was pulling the setup down. We also noted that if you change lens or move the camera so that it points at a different area of the sky, it is well worth checking the polar alignment in case it had been moved in the process. There is no doubt in our minds that iOptron is onto a winner with the SkyTracker, especially as there may be a possible bright comet – C/2012 S1 ISON – later this year. S

SKY SAYS… Now add these: 1. iOptron SkyTracker DSLR ball head 2. Sturdy tripod 3. iOptron iPhone/iPad polarscope app

VERDICT ASSEMBLY BUILD AND DESIGN EASE OF USE FEATURES TRACKING ACCURACY OVERALL

★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★

COMPASS AND SPIRIT LEVEL The compass at the top of the unit allows you to roughly align your setup northwards in circumstances when the pole star may not be visible – such as twilight. The spirit level allows you to level the mount before adjusting the latitude, but the compass spindle prevents it from reaching the centre of its dome.

CAMERA, BALL HEAD AND TRIPOD

ALL PHOTOS: PAUL WHITFIELD

NOT INCLUDED

SWITCHES The left switch at the top of this picture allows for northern or southern hemisphere tracking; the right switch allows you to select either 1x or 0.5x sidereal rate. The 1x sidereal rate is the normal motion of the stars but 0.5x sidereal rate gives good results for short exposures containing sky and foreground subjects together, keeping them both sharp.

Mysteries of Modern Physics: Time Taught by Professor Sean Carroll california institute of technology

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94

FIRST light Orion

SkyQuestXX16g

Dobsonian

SKY SAYS… The XX16g has a big aperture for great views but also offers the travelling convenience of a smaller telescope

A exceptionally solid man-sized telescope with great Go-To capabilities

WORDS: MARTIN LEWIS

VITAL STATS • Price £3,299 • Optics 406mm (16 inches), f/4.4 • Mount Dobsonian, computerised altaz Go-To • Focuser 2-inch dual-speed Crayford • Hand controller SynScan controller • Extras 28mm eyepiece, 12.5mm illuminatedreticule eyepiece, zero-power EZ finder, 2-inch to 1.25-inch adaptor, focus extender tube • Weight 79kg • Power 12V DC 2.1A (not supplied) • Supplier The Wideccreen Centre • www.widescreencentre.co.uk • Tel 020 7935 2580

L

arge aperture Dobsonian telescopes are ideal if you want spectacular deep-sky views. But what if you also want Go-To ability and a scope that fits easily in your car so you can travel with it to darker skies? If you want all of those things, then Orion’s new SkyQuest XX16g could be for you. The telescope has a 16-inch primary mirror with enhanced reflectivity coatings, as well as full Go-To capability and motorised tracking. But it can also be broken down into separate parts that will fit in an average car, allowing you to take it away from the city lights and make the most of that big aperture. The owner’s manual is nicely detailed. Photos showed exactly what is packed in each box and give comprehensive step-by-step assembly and operating instructions. Putting it together is a straightforward process, although the manual shows the differently designed cell for the smaller XX12g. Disassembling it into manageable parts to take outside or load into a car takes 5-10 minutes, while reassembly takes 20-25 minutes. The ground board is quite bulky, and slightly larger and heavier than perhaps it could have been. A fair amount of the assembly time was spent

ALL PHOTOS: PAUL WHITFIELD

THE SUM OF ITS PARTS Due to their sheer size, large-aperture commercial Dobsonians often present practical difficulties when it comes to moving them between observing sites. Orion’s XX16g overcomes many of these difficulties with an innovative design that enables it to be broken down into smaller and lighter parts. Like most big Dobsonians, the truss tubes separating the top and the bottom of the main tube can be easily removed, which saves considerable space. Where the XX16g is different is with its large and heavy rocker box, which houses

skyatnightmagazine.com 2013

the azimuth and altitude bearings. This rocker box can be separated into the baseboard and three side panels by undoing a set of hand bolts that screw into mating threaded bosses. This great idea means that the rocker box packs down flat and the whole telescope can be readily fitted inside a standard car. What’s more, it also means you can load and unload the telescope yourself without needing a second person to help, or resorting to the use of ramps and wheelbarrow handles like some owners of other big Dobsonians.

attaching the nine 1kg counterweights, which help balance the head unit that houses the secondary mirror. A lighter, less overly robust head would have eliminated this task and saved further weight. Minor collimation adjustment of the main mirror is always needed before observing – it’s a relatively painless procedure and fully explained in the manual. Setting up the Go-To requires a two-star alignment process. This involves manually centring a bright star in the supplied illuminated crosswire eyepiece, automatically slewing to the second and then using the motor control buttons to centre this second star.

Smooth operator We found the whole Go-To system to be wellbehaved and relatively simple to use. You can use the motors to automatically move to new objects or you can release the friction clutches and push it most of the way before finishing off with the motorised Go-To. If you do decide to push it, the closed-loop control means you won’t lose alignment when you unlock the bearing clutches. Whichever method you use, the accuracy seems to be the same and when >

FIRST LIGHT JUNE 95

FOCUSER The 2-inch Crayford focuser is a well-made, smooth-running unit, and includes a 10:1 speed reduction knob. A 2- to 1.25-inch adaptor is supplied. The focus position is quite a distance from the body of the telescope, which means having to use the supplied extender tube to achieve focus for some eyepieces.

HAND CONTROLLER The SynScan hand controller is the heart of the scope’s control system. It has a clear LCD display and tactile illuminated buttons – the four directional cursor keys offer manual control of the two drive motors. It has a database of 42,000 objects, including the Messier, IC and NGC catalogues, and supports custom lists.

OPTICS The enhanced reflectivity 16-inch primary mirror has a strongly convex back and is significantly thinned down at the edges, reducing weight and allowing it to reach ambient temperature more quickly. The mirror is mounted on its thick centre, which simplifies the support mechanics. The secondary obstructs 22 per cent of the view.

GO-TO MOUNT One of the great features of this scope is the Go-To system, which allows the scope to automatically seek out any object you select from the handset’s database. The motors continue to smoothly track the object once centred.

skyatnightmagazine.com 2013

96 FIRST LIGHT JUNE

FIRST light SKY SAYS… Now add these: 1. Case and shroud package 2. Orion heavy-duty trolley for large dobsonians 3. SkiFi wireless telescope controller

> you have found the target, wherever you’re pointing in the sky, the motors automatically continue to follow it. There’s no need for constant nudging and you can use the handset buttons to move the scope smoothly in any direction if you wander off target. Automatic tracking also enables you to have a go at planetary imaging using a video camera attached to the focuser. Astrophotography of brighter deep-sky objects may even be possible by stacking short exposures.

Enhanced appeal

MOTOR CLUTCHES You can loosen the XX16g’s motor drive clutches without losing alignment and push the scope around just like a conventional Dobsonian. Retighten the clutches to engage the motors and have the scope automatically track the object in the eyepiece.

On a night of good seeing, we found the optics of the scope gave us well-contrasted views of Jupiter and the Moon. And, of course, the sizeable aperture gave great views of deep-sky objects, including the Orion Nebula with its bat-like wings and the sweeping chains of stars of open cluster M35. The Go-To made viewing the centre of the Virgo Cluster a pleasure rather than a chore and then drove us on a short distance to view the faint but wonderful razor of edge-on galaxy NGC 4762. Star testing showed some minor differences either side of focus – possibly arising from uneven cooling of the mirror, which is substantially thicker at the centre than at the edges. The optional elasticated shroud helps keep thermal currents from an observer’s body out of the light path and noticeably improved images, but didn’t stop the secondary from dewing up after about two and a half hours. A lightweight extendable dew shield would help here. Overall, the XX16g’s innovative design features enhance the appeal of owning a large Dobsonian and we expect to see several at this year’s UK star parties. S

ASSEMBLY BUILD AND DESIGN EASE OF USE GO-TO ACCURACY STABILITY OVERALL skyatnightmagazine.com 2013

★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★

ALL PHOTOS: PAUL WHITFIELD

VERDICT

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Lamb Observatories Personal Viewing Environments for Astronomers Wooden Roll Off Roof Skyshed Observatory Manufacturers and Installers UK wide. Standard Skyshed models range from: 6’ x 6’ Remote Imaging set up and leave version through to 16’ x 10’ Observing+Control/Warm Room Skyshed. A bespoke service is also available. Visit our website for full specifications and prices. Observatory Relocation Service - please contact us for details. Customer focused guidance and assistance provided throughout to ensure your Skyshed layout and design fully meets your Observing needs.

[email protected] www.lamb.uk.com 07734 423300

98

FIRST light

Mesu-Mount 200

SKY SAYS… The Go-To was very accurate, with test stars appearing near the centre of our CCD sensor each time

Don’t let its industrial appearance and exposed bolts fool you; this mount is a triumph of design and engineering WORDS: STEVE RICHARDS

VITAL STATS • Price £4,899 • Load capacity 100kg visual, 75kg imaging • Hand controller SiTech wired eight-button handset • Database 45,516 objects • Flash upgradeable Yes • Autoguider port ST4 • Tripod None supplied • Weight Mount 25.7kg, Ccounterbalance bar 4.8kg • Supplier Modern Astronomy • www. modernastronomy.com • Tel 020 8763 9953

T

he Mesu-Mount 200 is unlike any other mount you will have seen before. Finished in stainless steel, black silk powdercoat and anodised alloy, it is a triumph of function over form. If you insist on sweeping curves and soft edges, you won’t find them here, but what you will find is solid, high-quality engineering. This mount is a pure engineering solution to a well-established problem – how to accurately locate and track celestial objects. When the Mesu-Mount 200 was originally released it shipped with a ServoCat mount controller for basic operation and an Argo Navis Digital Telescope Computer hand controller to add full Go-To functionality. Although this system worked very well, there were calls for full robotic control from imagers who required greater computer integration. Mesu listened to this feedback – the latest version reviewed here comes with the wellrespected and versatile SiTech Servo II controller from Sidereal Technology. The SiTech controller is a customisable system comprising an electronic interface and processor, ASCOM-compatible but slightly quirky mount control software and a simple hand controller. Various additional software tools are included to implement ‘plate solving’ (a very accurate method of determining exactly where your telescope is

ALL PHOTOS: STEVE RICHARDS

THE ART OF FRICTION Most mounts use worm gears to drive the axes, but no matter how well engineered the gear system may be, there is never a perfect mesh between the teeth of the various gears. Coupled with the machining tolerances, the presence of a thin layer of lubricating grease means there will always be some backlash in the system. Imperfections in the manufacturing process result in periodic error and although this can largely be corrected by autoguiding, backlash can never be completely eliminated which makes guiding more difficult. Rather than worm gears, the Mesu-Mount 200

skyatnightmagazine.com 2013

pointing) software-assisted polar alignment and automatic multi-point sky modelling. Each of these helps to improve the mount’s Go-To accuracy. Lifting the mount onto a pier or tripod is really a two-person task, as it weighs 25.7kg. However, assembly was straightforward, requiring approximate adjustment for your latitude, the attachment of the optional Losmandy- or Vixencompatible saddle clamp using four socket head bolts and the positioning of a 40mm-diameter counterweight bar into the base of the declination axis. The counterbalance bar has a neat ‘detent’, a device that stops it from sliding out of the mount head, and an undercut and toe protector to ensure that the counterbalance weights cannot inadvertently slip off. The mount is attached to the optional mounting plate with a single central 12mm bolt. Counterweights are not included as standard, but are available in various weights from third-party suppliers. Chrome-plated 5kg and 10kg Geoptik weights were supplied for the purposes of this review.

Technical prowess A bracket-mounted polarscope is available as an optional extra, but as this wasn’t supplied with the review unit we used the SiTech’s built-in polar alignment routine and achieved a satisfactory Dec. drive inspection plate

uses a friction drive – a small driven roller driving a reduction disc, which in turn drives the main disc and results in a 2000:1 reduction. This has advantages over a conventional system as it is easier to machine an accurate roller than it is a worm drive and backlash is completely eliminated, resulting in a very rigid drive system. Low-current servo motors are used to drive each axis and Mesu claims a periodic error of just 4 arcseconds peak to peak.

Dec. motor

Dec. drive housing

FIRST LIGHT JUNE 99

DUAL ENCODERS Both axes have two encoders, an eight million tic/revolution encoder on the motor and a 10,000 tic/revolution encoder on the axis shaft. These high-precision encoders work with the SiTech controller to ensure that the axes move very accurately when tracking and performing Go-To slews.

SITECH CONTROLLER The SiTech Servo II has a plethora of connections to control the mount, while inputs from up to four encoders can be analysed to correct the drive’s motion. A standard ST4 compatible autoguiding port, RS232 port and a USB port are also included.

MOUNTING PLATE A supplied optional mounting plate allows you to attach the MesuMount 200 to a pier, but – recognising that it is a natural upgrade to the popular NEQ6 mount – the plate has been drilled and countersunk so it can be installed on an EQ6 tripod or compatible pier head. The plate also retains the azimuth adjustment post.

ALTITUDE ADJUSTMENT Altitude adjustment from the equator to the zenith is achieved by altering the position of a substantial eyebolt on a quadrant-shaped plate with mounting holes tapped at 10º intervals. Fine adjustment is made using two knurled knobs working against a fixed post on the side of the mount.

skyatnightmagazine.com 2013

100 FIRST LIGHT JUNE

SKY SAYS… Now add these: 1. Illuminated polarscope 2. Mains power supply 3. Heavy-duty portable tripod

HAND CONTROLLER The eight-button hand controller has no built-in memory, but hides several features that become available depending on which mode the mount is operating in. With the exception of Go-To, the mount can even be fully operated without being connected to a computer using this device.

> alignment. Adjusting the altitude and azimuth settings was extremely easy using the substantial knurled knobs, having first selected the correct mounting hole for the eyebolt in the stainless steel altitude quadrant. The unusual friction drive is permanently connected, so there are no clutches as such, but the right ascension and declination axes can be locked by engaging two rotating, key-shaped hooks, which slot into matching cut-outs in each axis. With the hooks disengaged, the axes rotate freely, allowing accurate balancing to be carried out after the telescope has been attached. As the friction drive eliminates backlash, it is not necessary to offset the balance for autoguiding as you have to with a worm gear drive. After carrying out a basic two-star alignment the Go-To was very accurate, with test stars appearing near the centre of our CCD sensor each time. Go-To accuracy was further improved by adding more alignment stars. The Mesu-Mount 200 will be of particular interest to astrophotographers so we were keen to see how it lived up to its specification regarding periodic error, which has a large effect on image quality and star shapes. The lower the periodic error the better and in our tests we measured this at 4.37 arcseconds peak to peak (1.22 arcseconds root mean squared), which was an excellent result close to the manufacturer’s claim. We would highly recommend this mount to any advanced astrophotographer wishing to make the leap to a true observatory-class imaging mount. S

VERDICT ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★ ★★★★★

ASSEMBLY BUILD AND DESIGN EASE OF USE GO-TO ACCURACY STABILITY OVERALL

TR I PO DN IN OT D CLU ED

skyatnightmagazine.com 2013

ALL PHOTOS: STEVE RICHARDS

FIRST light

The next generation of solar filters and telescopes

H-alpha Telescopes and Filter

Ca-K Filter

White-Light Solar-Prism

Ask your local dealer for the advanced solar telescopes and filters of Lunt Solar Systems, or visit our European homepage:

www.lunt-solarsystems.eu Exclusive E l i E European Di Distributor ib - Optus O GmbH G bH

102

Books New astronomy and space titles reviewed

Red Rover

NASA/JPL-CALTECH, LESLIE E. BUCKLIN

Roger Wiens Perseus £17.99  HB Lowered onto an alien world by a rocket-supported crane, the robot explorer determines the chemical composition of the native soil by firing a laser and analysing the resulting flash with instruments in its mobile lab. This reads like science fiction, but Wiens’s accessible and conversational it is actually the true story of NASA’s writing is a major strength of Red Rover, Curiosity rover, which has been roaming providing a thoroughly human perspective the surface of Mars for almost a year. on a complex technological subject. From How do such seemingly far-fetched, flashbacks to a childhood spent making complex and expensive space missions model rockets and spying the Red Planet make the leap from innovative concept from afar, to comments on making time to scientific reality? This engaging for family amid feverish new book by Roger Wiens, preparations for launch, the whose team built book conveys the story not Curiosity’s ChemCam just of space missions instrument, gives a but of a scientist’s life unique insider’s view. spent in their service. Despite its Some sections of title, Red Rover overlapping narrative isn’t limited to the detailing various author’s involvement instruments are awash in Curiosity. Instead, in acronyms and tend this highly personal to drag. But these sit account spans more among rich recollections than two decades of of workplaces, launches and experience working on landings, as well as fascinating space missions. Early chapters Curiosity’s sky crane landing was straight out insights into the high-stakes relate to Genesis, which of science fiction politics, intricate collaboration collected samples of the solar and sheer determination that gets new wind and returned them, with instruments into space. Overall, a good an unexpected crash landing, to read for anyone interested in the robotic Earth. Additional sections describe exploration of our Solar System. the development of another mission – cancelled due to lack of funding – that ★★★★★ aimed to bring back some of Mars’s atmosphere. The rest of this enjoyable OLIVIA JOHNSON is an astronomer book chronicles the laborious but specialising in science education ultimately exhilarating journey of ChemCam from a New Mexico lab to Reader price £17.99, subscriber price £17.99 Mars’s Gale Crater. P&P £1.99 Code: S0613/1 skyatnightmagazine.com 2013

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

2 MINUTES WITH ROGER WIENS What inspired you to write this book? While working on these missions I had the distinct feeling that real life is stranger than fiction. I had a story that space enthusiasts would love to read and I wanted to give them the opportunity. What’s your role on the Curiosity mission? I lead the ChemCam laser instrument team. Our team plays a big role in the overall conduct of the mission, helping to decide what the rover will do and where it will go. What has been the most exciting moment in the mission for you, so far? The landing. It was a huge risk to land a $2.5 billion rover with a method that had never been tried. As the book describes, I had experienced the crash of an earlier NASA mission – a landing that should have been much simpler than the ‘sky crane’ on Curiosity. What has been the biggest challenge for the mission? Never before has so much equipment been packed into a single rover and we all have to share the resources. The pace of activity with Curiosity is often slow. So while it is exciting the mission requires a little patience. What are you most looking forward to exploring with the rover? Gale Crater is unlike any other place we’ve explored on Mars. Curiosity landed next to a 5km-high mountain with towering canyons. Driving up into this terrain is going to be really surreal. ROGER WIENS is the principal investigator for Curiosity’s ChemCam instrument

BOOKS JUNE 103

Stargazing for Dummies Steve Owens Wiley £12.99  PB

OKE BO F TH

O N TH MO

Stargazing for Dummies is a terrific book. It will make you laugh from cover to cover and is one of the best introductions to practical astronomy on the market. The book has been crafted to be your stargazing adventure. It begins with how the sky changes before guiding you through your first observing trip. The next few chapters deal with binoculars, telescopes and astrophotography before delving into the constellations and how to find them by star hopping. There’s also a detailed month-by-month look at the major constellations, with all their prime stars and nebulous inhabitants mentioned. Author Steve Owens includes southern constellations too – essential for stargazers planning a trip to the

The Day Without Yesterday Stuart Clark Polygon £12.99  HB The Day Without Yesterday is a novel that traces the lives of two of the most significant figures involved in the growth of our understanding of the Universe. The book is the final part of The Sky’s Dark Labyrinth trilogy, and takes its title from the words uttered by George Lemaître to Albert Einstein during their meeting at Caltech in 1933, when Lemaître stated, “There was once a day without yesterday” as he attempted to sum up his thoughts on the beginning of the Universe. Putting the story across in a way that brings out the characters remarkably well, the book initially alternates between the Belgian mathematician and theoretical cosmologist Lemaître’s experiences on the battlefields of World War I, and the

Antipodes. Plus, there is a guide to the objects only visible in really dark skies – the author being a determined campaigner against light pollution. What makes Stargazing for Dummies so approachable is that you can dip into it wherever you like. Many novice stargazers are a bit awed, even frightened by the heavens – although they know they’re fascinated. Owens’s style allows you to flick through to find what’s grabbing you about astronomy at any given moment. It’s organised into bitesized chunks with suggestive headlines such as ‘The red light district’ – alluding to the fact that red light torches are better than white ones when out observing. There are no colour images, but plenty of good and accurate diagrams, ranging from the anatomies of binoculars and telescopes to constellation patterns. This is the perfect book to get you started. Enjoy!

★★★★★ HEATHER COUPER is an astronomy broadcaster and writer Reader price £11.99, subscriber price £10.99 P&P £1.99 Code: S0613/4

turbulent domestic life of physicist Einstein in Berlin. As the book moves through the years we learn of Lemaître’s growing belief in an expanding Universe and his eventual theory, outlined by him to Einstein, that there was a moment at which the Universe came into being. In other words, there was a beginning of time and space, or a day without a yesterday. Ordained as a priest, Lemaître was careful to draw the distinction between theology and a Universe created by God, and the scientific concept of a Big Bang. The Day Without Yesterday balances cosmological fact and personal insight well, bringing the reader’s attention to the science without taking away interest in the characters involved. It provides just enough information on the personal lives of Lemaître and Einstein for the reader to feel very much involved with their story.

21st Century Atlas of the Moon Charles Wood and Maurice Collins Lunar Publishing £19.99  PB Planetary scientist Charles ‘Chuck’ Wood is an eminently qualified pre-Apollo selenographer – someone who studies the lunar surface. He’s written a monthly Moon column since 1998 and blogs daily for website Lunar Photo of the Day. His 111-page atlas is co-authored with award-winning imager Maurice Collins, incorporating the latest high-resolution shots from NASA’s Lunar Reconnaissance Orbiter. Supplementary images come from the Clementine, Lunar Orbiter IV and Chandrayaan-1 probes, in addition to the venerable Consolidated Lunar Atlas. A detailed introduction to lunar geology and nomenclature precedes 28 stunning maps of the near side of the Moon arranged in order of the waxing terminator, so you can follow the westward march of the lunar sunrise on successive pages. Most maps neatly incorporate detailed descriptions from Wood’s Lunar 100 — a list of interesting objects ranked in order of increasing observing challenge. Additional maps of the lunar poles, landing sites and the far side follow, with an index of more than 1,200 feature names. Sadly, there are errors. For example, on the lunar near side map Crater Deslandres and the Mare Tranquillitatis are misspelt, and elsewhere a description of Crater Plinius is illustrated by Crater Eratosthenes. In all, I found about 20 typos, indicating the value of thorough proofreading in the publishing process. However, these are minor detractions from a valuable work that is destined to become a classic.

★★★★★

★★★★★

ADE ASHFORD is an astronomy writer

BRIAN JONES has written 15 books on astronomy and space

Reader price £37.50, subscriber price £37.50 P&P £1.99 Code: S0613/2

Reader price £11.99, subscriber price £10.99 P&P £1.99 Code: S0613/3

skyatnightmagazine.com 2013

104 GEAR JUNE

Gear

Vincent Whiteman rounds up the latest astronomical accessories

1

4 1 Altair Sabre

Price £230 • Supplier Altair Astro 01263 731505 • www.altairastro.com Made in the UK, the Sabre is an altazimuth mount designed to hold two telescopes. A special friction dampener allows easy slewing, for a Dobsonian-style experience with a reflector or refractor.

2 Galaxy Sweater

Price £39.99 • Supplier Firebox 020 0044 5010 • www.firebox.com Decorated with a spectacular interstellar view, this colourful jumper will not only show off your love of space but also keep you warm.

5

3 Seymour Solar SF950 Glass Solar Filter

2

Price £79.99 • Supplier Rother Valley Optics 01909 774521 • www.rothervalleyoptics.co.uk This 9.5-inch solar filter gives an orange-yellow view of the Sun. A list of compatible scopes can be found on the supplier’s website.

4 Camera Tilting Unit

Price £253 (€299) • Supplier Gerd Neumann jr [email protected] • www.gerdneumann.net The camera tilting unit aims to correct problems in CCD focusing by aligning the camera chip as precisely as possible to your optical axis. Three screws adjust the camera’s tilt by tiny amounts until it’s more parallel to the focal plane.

5 Hyperflex-7E2 Zoom Eyepiece

3

Price £129 • Supplier Optical Vision 01359 244255 • www.opticalvision.co.uk

Boasting clear, distortion-free views, this high-performance 1.25-inch zoom eyepiece gives focal lengths between 9mm and 27mm with an apparent field of view of 40-60°.

6 Canon T-ring with H-Alpha Filter

Price £178 • Supplier 365 Astronomy 020 3384 5187 • www.365astronomy.com This accessory allows you to attach a Canon DSLR to a telescope and take h-alpha 7nm narrowband images. The protective T-ring keeps out dust and humidity. DSLR not included.

skyatnightmagazine.com 2013

6

Observing the Sun through an h-alpha filter is an incredible experience… Solarscope manufacture complete h-alpha telescopes available in unobstructed 50mm and 60mm apertures as well as a range of h-alpha lter systems which can convert your existing astronomical telescope into a high quality solar instrument. H-alpha lter systems are available in unobstructed 50mm, 60mm, 70mm and 100mm aperture sizes. The dedicated Solarview (SV) telescope range provides you with everything you need to observe the Sun in h-alpha apart from a mount and clear skies! These solar instruments are manufactured to the highest quality and will give you views of our nearest star which will literally take your breath away. The solar lter system (SF) range consists of a totally unobstructed front mounted etalon with a matching rear mounted blocking lter which ts into your telescopeís eyepiece holder. A custom made adapter plate is used to securely mount the etalon over the front of your telescope. Using laser industry techniques our lter systems are manufactured to the highest optical tolerances.

Prestige hydrogen-alpha solar lters manufactured in the Isle of Man

For information on Solarscope filters Contact: Ken Huggett

07624 435572

[email protected]

www.solarscope.co.uk

106 EXPERT INTERVIEW JUNE

WHAT I REALLY WANT TO KNOW IS…

Can robots build us a base on Mars? André Schiele is developing technology that will allow machines to work for humans in space INTERVIEWED BY PAUL SUTHERLAND

R

obots are becoming more and more important in space exploration. They are in use already – the NASA rovers trundling about on Mars are robots, for example. I’m working at ESA to help improve the technology that allows robots to work together to perform more complex tasks. In the future they could help us to build bases on other worlds or mine asteroids. There are two kinds of robotic developments going on at the moment. The first is mainly for scientific projects or geological investigations exploring planetary surfaces. That started with the Sojourner rover, then Spirit and Opportunity, and now Curiosity. These Mars rovers are typically controlled from Earth in a very indirect way. Scientists and engineers on Earth plan what investigations to do, check and validate that with the robot and then, once the commands have been run through simulators, they are radioed across space to the rover itself.

NASA

Operational issues It is not practical to drive a rover in real-time from mission control because there is always a delay of up to 40 minutes between issuing a command and getting a response, depending on how far apart the Earth and Mars are in their orbits. Engineers have been working to get round this by shifting more autonomy onto the robot itself – essentially allowing more local decision-making on Mars. Late in the missions of Spirit and Opportunity, software patches were uploaded to help them avoid hazards and obstacles, for example. The other big string of robotics is used in Earthorbiting spacecraft such as the International Space Station (ISS), as well as those that capture and repair satellites or remove space debris. Because the distances are comparatively small they can be directly controlled, with time delays of 20-500 milliseconds. skyatnightmagazine.com 2013

Robonaut 2 is in operation aboard the ISS; here it is measuring air velocity in the Destiny lab module

ABOUT ANDRÉ SCHIELE Dr André Schiele founded and runs ESA’s telerobotics and haptics laboratory at Noordwijk in the Netherlands. He is principal investigator for the ISS METERON project and has helped develop technology for Mars rovers and some exoskeleton human robot interfaces.

ESA and NASA have been working together on a new type of interplanetary internet, the Disruption Tolerant Networking protocol; last year NASA astronaut Sunita Williams used a laptop to control a small ESA robot rover in Germany from the ISS. And NASA has installed a humanoid robot called Robonaut 2 on the ISS. This is the sort of robot that NASA and ESA are designing; one that will be able to carry out similar functions to astronauts, using similar tools. When humans fly to Mars we want to send robots first to prepare the way for them, performing the manual hard labour. Then when the astronauts arrive, they can wait in orbit for the robots to finish building the base where they will live and work. Only as the work nears completion will the crew need to land on the Martian surface to carry out the final touches. In Europe we have initiated a project called METERON (Multi-Purpose End-To-End Robotic Operation Network) to make controlling groundbased robots easier from space. The Mars robots will be far more advanced, but our controls need to be developed so that they are more intuitive; something like an iPhone for robots. To build a robot like this involves a number of disciplines – mechanics, electronics, motors, control algorithms and software – all of which are interrelated. If you want your rover to look at rocks and get geological information, it will look very different to a robot that you would need to set up a habitat, for example. The communications system will be equally important because these robots will have to work with each other as well as with their human controllers. But once all of the practicalities are solved, we may be able to look forward to the first Mars colony, built by robots, in 20 or 30 years time. S

SOUTHERN HEMISPHERE IN JUNE With Glenn Dawes

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The far southern Milky Way is on show in June. Our Galaxy’s inclination to the celestial equator is easily noticeable, its starry road coming within 16° of the south celestial pole in the constellation of Musca, the Fly. Musca’s trapezium of four 3rd- and 4thmagnitude stars is directly south of (below) the Southern Cross. To its east (left) lies the distinctive constellation of Triangulum Australe. Atria (Alpha (a) Triangulum Australis) and Miaplacidus (Beta (b) Carinae) are the closest 2nd-magnitude stars to the pole.

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With solar maximum expected in the coming months we can look forward to a peak in sunspot numbers and auroral events. The position of the south magnetic pole favours aurora hunters in southern Australia, so keep an eye out if you are in the area. The Theta Ophiuchid meteor shower peaks around the 10th, close to new Moon. There has been renewed interest in the shower in recent years with a number of fireballs reported. It is best observed after midnight, with its radiant in Ophiuchus.

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PLANETARY NEBULA

AQUARIUS

The end of the Dark Doodad and Gamma Muscae form an equilateral triangle with mag. +7.2 globular cluster NGC 4372 (RA 12h 25.8m, dec. –72° 39’). The cluster is large (visually 8 arcminutes), with no obvious central brightening, and contains a smattering of resolvable stars, including one shining at mag. +6.6 on its northwest edge. Nearby mag. +3.5 star Beta (b) Muscae is a brilliant double.

CHART KEY

GLOBULAR CLUSTER

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The remarkable dark nebula in Musca known as the Dark Doodad (centred on RA 12h 28.5m, dec. –71º 19’), pictured, is 3° long but quite narrow, only 5 arcminutes wide. Through binoculars this black streak across the Milky Way looks more like a rift than a silhouetted cloud. It runs in a north-south direction, with its southern extremity about 0.7° west of mag. +3.8 star Gamma (g) Muscae.

OPEN CLUSTER

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DEEP-SKY OBJECTS

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The real evening performer will be Saturn, which is due north around 21:00 EST mid-month. Turning to the morning, Mars is visible low in the eastern dawn sky. The Red Planet remains a morning object for the rest of the year.

EAST

Venus is back in the evening sky for the remainder of 2013. During June, this brilliant beacon is low to the northwest in the early evening sky, passing 2° below Mercury on the 21st. The two inner worlds will set near to the end of twilight.

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skyatnightmagazine.com 2013