BBC Sky at Night 2013-12

R EEENDA FR CAL

14 20

More from your equatorial mount Set up easily with a red light polar finder

Colossal collisions Why galaxy mergers are getting a second look

ALSO IN THIS ISSUE

Caldwell challenge: observe Patrick’s top deep-sky sights Takahashi’s mighty 10-inch scope tested Discover the space art of a forgotten master Celebrating in orbit: Christmas on the ISS DECEMBER 2013 #103 www.skyatnightmagazine.com

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LETTER FROM THE EDITOR DECEMBER 03

Welcome

This month’s contributors include...

FREE

Christmas brings fond memories and sharp reflections

MARK PARRISH AMATEUR SCOPE MAKER

Mark shows us how to get more from an EQ1 mount with a home-made polar finderscope in this month’s How to. MARK PAYNE-GILL BBC CAMERAMAN

Mark reviews the Mallincam Xtreme, a colour video CCD camera that can produce live images of the night sky on a TV screen. ELIZABETH PEARSON STAFF WRITER

Elizabeth talks to astronauts Chris Hadfield and Tom Marshburn to find out what Christmas on the ISS is really like. EMILY WINTERBURN ASTRONOMY HISTORIAN

Emily delves into the tale of the Star of Bethlehem – was it a supernatural event, a work of fiction, or based on a glimmer of truth?

Christmas is a time for gathering with those close to us, but for the crew of the International Space Station, it’s a time of year when the 350km that separates the orbiting outpost from Earth can seem farther than ever. Turn to page 42 to hear from ISS crewmembers who have spent the festive season in space about how they make the holiday as memorable as possible. For many of us, reflecting on the Christmas just past can’t be done without some poignancy, for it was when we lost Sir Patrick Moore. Steve Richards marks the first anniversary of his passing on page 35 this month, with an observing challenge based on the Caldwell Catalogue, the compendium of deep-sky objects that Patrick put together. Patrick would doubtless have been fascinated by Will Gater’s feature on page 62, which uncovers the wildly unfamiliar environments in which alien worlds have been discovered so far. And staying with exoplanets, I’m delighted to introduce a new columnist this month – Jon Culshaw. Jon will be travelling to more of these strange and distant worlds each month, using the latest science and his versatile imagination to present the view of these alien vistas. Turn to page 23 for his first installment. Enjoy the issue, and seasons greetings!

Chris Bramley Editor

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skyatnightmagazine.com 2013

04 CONTENTS DECEMBER

In the magazine ON THE COVER 62

58

62

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

THE PLANETS THAT SHOULDN’T EXIST

90

80

90

14

35 69

42

FEATURES

06 Eye on the sky COVER IMAGE: ESO/L. CALCADA, THIS PAGE: NASA/JPL-CALTECH/R. HURT (SSC), THINKSTOCK, WWW.THESECRETSTUDIO.NET

Stunning new images of space.

35 The Caldwell challenge Take a trip through Patrick Moore’s own observing catalogue with our special 15-stop tour.

42 Christmas on the ISS The astronauts of the ISS tell us how they deal with Christmas without family, friends or eggnog.

35

THE CALDWELL CHALLENGE

REGULARS 11 Bulletin The latest astronomy and space news.

19 What’s on 20 Sky at Night diary Your backstage pass to the TV show.

23 Jon Culshaw NEW The first monthly off-world travelogue.

62 The planets that shouldn’t exist

24 Interactive

From the jaws of a black hole to the firing line of a pulsar, it seems planets pop up in the strangest places.

28 SUBSCRIBE

69 The forgotten space art of Scriven Bolton

30 Hotshots

We pay homage to the greatest space artist and illustrator that most have never heard of.

73 READER SURVEY Help shape the magazine and win an iPad mini.

skyatnightmagazine.com 2013

FIRST LIGHT

Your letters, emails and tweets.

The very best of your astro images.

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

78 Skills 78 The guide The real Star of Bethlehem.

80 How to Build a polar finderscope.

82 Sketching The Aristarchus Plateau.

87 Scope doctor

89 Reviews First Light 90 Takahashi CCA-250 corrected Cassegrain astrograph.

94 William Optics ZenithStar 71 ED doublet refractor.

98 Mallincam Xtreme colour video CCD camera.

102 Books 104 Gear

What I really

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

ESO

Prawn cocktail New stars bathe in ultraviolet radiation in this enormous stellar nursery in Scorpius

EUROPEAN SOUTHERN OBSERVATORY 18 SEPTEMBER 2013

The Prawn Nebula, a vast stellar nursery that spreads across 250 lightyears, glows brilliantly in this vibrant image taken by ESO’s Very Large Telescope in Chile. Intensely bright, newborn stars pierce through the bulbous gas clouds, emitting extremely powerful ultraviolet radiation and causing the clouds to glow. This radiation strips electrons from hydrogen atoms within the clouds. After recombining in this stellar soup, they release energy

in the form of light. Hydrogen atoms predominantly emit red light, which gives the Prawn Nebula its characteristic dark pink colour. This enormous star-forming region has produced many single stars and star clusters over the past few million years. The scattered cluster that covers most of this image is Collinder 316. The darker areas are cavities where interstellar material has been expelled by winds from nearby hot stars.

ESA/HUBBLE & NASA X 2, NASA/JPL/UNIVERSITY OF ARIZONA, NASA/JPL-CALTECH/SPACE SCIENCE INSTITUTE

08

There she blows X  MARS RECONNAISSANCE ORBITER 18 SEPTEMBER 2013 Two types of windblown sediment can be seen in the valleys and canyons of Mars’s Noctis Labyrinthus region in this image. The first type of sediment forms the network of pale crests, called tranverse aeolian ridges, on top of which lie darker dunes of iron-rich volcanic rock grains.

skyatnightmagazine.com 2013

EYE ON THE SKY DECEMBER 09

W Spectacular spiral HUBBLE SPACE TELESCOPE, 2 SEPTEMBER 2013 Spiral galaxy IC 2560, otherwise known as the Air Pump, is part of the Antlia Cluster, a collection of more than 200 galaxies over 110 million lightyears away from Earth that are bound to one another by gravity. The galaxy’s spiral arms and barred structure surround a bright centre, thought to be superhot gas driven from its black hole.

▲ Worlds apart CASSINI SPACECRAFT, 31 JULY 2013 NASA’s Cassini spacecraft spots two of Saturn’s very different moons, Mimas and Pandora, floating above the gas giant’s rings in this stunning shot. Tiny Pandora, just 81km across, sits just below 391km-wide Mimas. The smaller moon lacks the gravity needed to form itself into a sphere – as its far larger sibling has done.

A dusty veil X HUBBLE SPACE TELESCOPE 26 AUGUST 2013 Lenticular galaxy PGC 10922 appears to be cocooned by a shell of dust in this serene image from Hubble. The galaxy’s central region is surrounded by an array of halo-shaped ribbons of dust spreading outwards. Astronomers believe that this unusual structure may be the result of a collision or merger with another galaxy.

skyatnightmagazine.com 2013

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BULLETIN DECEMBER 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

The unusual behaviour of the pulsar may be down to it drawing material from a companion star

Comment

by Chris Lintott

Missing link in pulsar evolution found

ESA

The two-faced neutron star leads a double life ASTRONOMERS HAVE DISCOVERED an unusual pulsar that rapidly flips between emitting X-rays and radio waves. They say it’s a long-sought missing link in pulsar evolution. “We’ve been looking for such evidence for more than a decade,” says team leader Alessandro Papitto from the Institute of Space Studies in Barcelona, Spain. Pulsars are a type of neutron star. They can form when a massive star explodes, its core collapsing into a superdense ball that is only about 15km wide. Often they emit bright beams of radiation from their magnetic poles – if the beams sweep towards our planet as the neutron star rotates, these can appear to us as regular pulses. Sometimes the pulses are radio waves, but if material from a companion star streams off and

pounds the pulsar, the pulsar emits high-energy X-rays. Now Papitto’s team has found the first example of a pulsar that flips from one mode to the other. The pulsar lies in a star cluster about 18,000 lightyears away. It’s likely that material from a small companion star is hitting the pulsar, making it change from a radio emitter to an X-ray emitter over just a few weeks. “It’s like a teenager who switches between acting like a child and acting like an adult,” says team member John Sarkissian, who observed the pulsar using the Parkes Radio Telescope in Australia. The pulsar will probably mature into a constant radio emitter as matter from the companion star runs out. > See Comment, right

The story of this discovery began with the detection of a burst of high-energy gamma-rays by the INTEGRAL space telescope. Swift, another orbiting sentinel, quickly got involved, using its X-ray telescope to monitor the now-fading burst. More sensitive X-ray observations followed with XMMNewton, while a search through the archives of yet another, Chandra, also revealed the pulsar. Realising the shift back from bright gamma- and X-ray source to radio pulsar was imminent, the team then took advantage of a trio of radio telescopes: Green Bank in the US, Parkes in Australia and Westerbork in the Netherlands. Reading about these seven very different facilities combined made me realise how lucky we astronomers are. We have access to a remarkable spread of facilities, each the result of decades of work from hundreds or thousands of people, and when they work together – as in this discovery – the results can be breathtaking. CHRIS LINTOTT presents The Sky at Night on BBC TV

skyatnightmagazine.com 2013

12

Water found in rocky planet debris The remains suggest that many similar planets could be habitable

News in brief MARS ROCK IS SURPRISINGLY FAMILIAR NASA’s Curiosity rover has found a rock on Mars that’s uncannily similar to some on Earth. The Martian rock, which is about 50cm tall and shaped like a pyramid, is chemically almost identical to mugearite, an igneous rock sometimes found on Earth’s oceanic islands. “If this rock were found on Earth, we would be hard pressed, based on its elemental composition, to tell it was not an Earth rock,” says Edward Stolper from the California Institute of Technology. His team hopes the finding could clarify the history of Mars’s interior and how it compares to other rocky planets.

MARK A. GARLICK/SPACE-ART.CO.UK/UNIVERSITY OF WARWICK AND UNIVERSITY OF CAMBRIDGE, NASA/JPL-CALTECH/MSSS, NASA/ESA/A. VAN DER WEL, MPIA/V. CH. QUETZ

The existence of the asteroid provides hope that there are other water-rich planets somewhere in the cosmos

ASTRONOMERS HAVE FOUND the first evidence for plentiful water on a rocky alien world – in the remains of an asteroid ripped apart by a white dwarf. Observations of the dust and debris surrounding GD 61 in Perseus revealed a surprisingly high amount of oxygen, implying that it came from a larger rocky body torn apart by the dying star’s gravity. The results infer that this body was composed of 26 per cent water by mass; by contrast, only 0.023 per cent of Earth’s mass is water. “Those two ingredients – a rocky surface and water – are key in the hunt for habitable planets outside our Solar System so it’s very exciting to find them together for the first time,” says Boris Gänsicke from the University of Warwick. White dwarfs are elderly Sun-like stars that have run out of fuel and shrunk into hot, dense balls roughly the size of Earth. Gänsicke and his colleagues used data from Hubble and the Keck Observatory in Hawaii to study GD 61, which lies approsimately 170 lightyears away. skyatnightmagazine.com 2013

It appears that the star shredded an orbiting minor planet at least 90km wide. Possibly, it was a larger body similar to the dwarf planet Ceres in our Solar System. Bodies like Ceres and many asteroids are water-rich and may have supplied the bulk of our water on Earth. To date, astronomers have observed the debris of destroyed extrasolar planets orbiting 12 white dwarfs. But this is the first time they have found the signature of water. Team leader Jay Farihi from Cambridge University says it suggests habitable rocky planets may be common. “The finding of water in a large asteroid means the building blocks of habitable planets existed – and maybe still exist – in the GD 61 system, and likely also around a substantial number of similar parent stars,” says Farihi. “A system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces.” www.hubblesite.org

NEPTUNE’S MISSING MOON REDISCOVERED A ‘lost’ moon of Neptune has been located in archived data from the Hubble Space Telescope. Naiad, the planet’s innermost known moon, was discovered by NASA’s Voyager 2 in 1989 but hadn’t been seen again until now. “Naiad has been an elusive target ever since Voyager left the Neptune system,” says Mark Showalter from the SETI Institute in California, whose team rediscovered Naiad. The moon is roughly 100km across, but very difficult to detect due to Neptune’s glare.

BULLETIN DECEMBER 13

GRAVITATIONAL LENS IS FARTHEST YET THE MOST DISTANT ‘gravitational lens’ ever seen has been spotted in images taken by the Hubble Space Telescope. The gravity of the lens – presumably a massive galaxy – magnifies and distorts the light from a background galaxy directly behind it into a ring shape. How the background galaxy gets distorted can reveal things about the lens, such as its mass. Arjen van der Wel from the Max Planck Institute for Astronomy in Heidelberg, Germany, was reviewing observations from an earlier project when he noticed the curious lensed galaxy. Further investigation showed that it is the most distant lensed galaxy on record; the light has taken around 9.4 billion years to reach Earth after being deflected by the lens. “This has been a weird and interesting discovery – it was a completely serendipitous find,” says van der Wel. www.hubblesite.org

News in brief PLANETS SKIM THEIR STARS

The white central glow is the normal galaxy; the colourful rings around it mark the much more distant lensed object

A new planet-hunting survey may have revealed alien worlds so close to their host stars that they are nearly skimming the stellar surface. A team led by Brian Jackson from the Carnegie Institution for Science in Washington made the discovery in observations by NASA’s Kepler spacecraft. They found several potential planets with orbital periods less than 12 hours – some had orbits as short as four hours. One of these, Kepler-78b, is the first planet with an Earthlike density ever found.

The stars come out for Patrick@Night Amateur and professional astronomers raise a glass to the late presenter Moore Beer, the brew developed specially for this event

STRANGE LONELY PLANET REVEALED The xylophone was close to Patrick’s heart Jon Culshaw honours the late presenter

ASTRONOMERS GATHERED TOGETHER on 28 September to celebrate the life and work of the late Sir Patrick Moore. As he had done in life, the Patrick@Night event at the National Space Centre in Leicester united amateurs and professionals in a common cause, good company and good cheer. “If astronomy itself had a personality, it would have the personality of Sir Patrick Moore,” said Sky at Night presenter Jon Culshaw as he addressed the crowd. Culshaw went on to unveil a wonderful bronze bust of the great man, complete with his

Patrick’s bronze bust took pride of place

trademark monocle. Guests heard xylophonists from Loughborough Endowed Schools play three of Patrick’s compositions and were able to watch videos of his Apollo 11 coverage from a mock mission control – all while enjoying a glass of specially created ‘Moore Beer’. It was an event, says Sky at Night presenter Chris Lintott, that Patrick would have loved. “He would have enjoyed being the centre of attention,” says Lintott. “He would have been holding court next to the bust of himself and enjoying himself immensely.”

A free-floating planet that does not orbit a star has been spotted just 80 lightyears from Earth. Astronomers discovered the faint world using the Pan-STARRS 1 telescope in Hawaii. “It has all the characteristics of young planets found around other stars, but it’s drifting out there all alone,” says team leader Michael Liu from the University of Hawaii. The planet, a gas giant, is only thought to have formed about 12 million years ago and has a mass six times that of Jupiter.

skyatnightmagazine.com 2013

14

CUTTING EDGE

Our experts examine the hottest new research

Mergers may not be distractions after all The apocalyptic clash of two galaxies really could be a key step in their evolution WORDS: CHRIS LINTOTT Mergers seem to be quite common, not to mention integral in creating new stars

forming stars. For each of these star-forming galaxies, they took a careful look for any disruption that might indicate a merger in progress. The results of all that hard work are almost unequivocal. Those galaxies that shine most brightly in the infrared, and which therefore have the most current star formation, are much more likely to have traces of a merger. This is especially

NASA/ESA AND THE HUBBLE HERITAGE TEAM (STSCI/AURA)-ESA/HUBBLE COLLABORATION

T

he recently deceased Herschel Space Observatory was an incredible beast, with the largest mirror ever to fly into space. Deprived of the coolant required to keep its infrared eye in working order, it was shut down in summer 2013, but science will keep flowing from the mission for many years yet. Among the recent results produced using data from the spacecraft, a study led by Chao-Ling Hung of the University of Hawaii stands out. It tackles one of the key disputes in modern studies of galaxy formation and evolution head on: the role of galactic mergers in shaping the population of systems we see today. Mergers between large galaxies seem common enough, perhaps a matter of a once-in-a-billionyears event for a system the size of the Milky Way. It’s also clear that mergers can sometimes be a big deal – one way elliptical galaxies form is from the wreckage of two spirals smashing together – but if mergers are to have an impact on galaxies as a whole, they need to produce lots of stars. If that’s what’s happening, then it seems reasonable to expect the galaxies with the highest star formation rate to be mid-merger. Hung and the team set out to test this idea with more than 2,000 galaxies gathered from a Herschel survey of a 2º square patch of sky. This is hardly new territory – the region, about four times the size of the full Moon, was previously used for Hubble’s COSMOS survey and must be just about the most studied area in the entire celestial sphere – but Herschel’s far-infrared view is unique, allowing astronomers to pick out systems that are currently skyatnightmagazine.com 2013

“Those galaxies that have the most current star formation are much more likely to have traces of a merger”

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

true for those that have more star formation than might be expected for a galaxy of their mass – and it’s been true for at least the past seven billion years or so. Mergers, then, make a difference – a significant blow against the growing consensus that seemed to be pointing toward a view in which mergers were spectacular distractions, ultimately insignificant in galactic evolution. However, the picture is still confused, as the study also shows that many of the most massive and most luminous galaxies seem to be mergers, but have just the amount of star formation you might expect for galaxies of their bulk. In other words, their fate seems unchanged by a major collision. As ever with untangling the complex and messy story of galaxy evolution, it seems the devil is in the detail and there is plenty more argument to be had yet.

CHRIS LINTOTT was reading… The role of galaxy interaction in the SFR-M relation: characterising morphological properties of Herschel-selected galaxies at 0.2
BULLETIN DECEMBER 15

2013 TV135

News in brief

New menacing asteroid discovered

Mars

It could make a close pass of Earth, but the risk of an impact is tiny

A mysterious black pebble found in the Sahara Desert could be the first direct evidence of a comet striking Earth. Scientists who have analysed the pebble conclude that it is the first known specimen of a comet nucleus, rather than simply an unusual type of meteorite. The comet is believed to have hit Earth 28 million years ago. Comet fragments have not been found on Earth before except as dust particles, while returning small samples from space requires expensive spacecraft missions. “Now we’ve got a radical new approach to studying this material, without spending billions of dollars,” says team leader Jan Kramers from the University of Johannesburg.

TERRY BAKKER, ESO/C. PONTONI, NASA/JPL-CALTECH/MIT, NASA/JPL

ALMA ARRAY IN CHILE COMPLETE The final antenna for the Atacama Large Millimeter/ Submillimeter Array (ALMA) has been delivered, bringing the total number of antennas at the Chilean observatory to 66. ALMA is already studying some of the coldest and most distant objects in space, including remote galaxies.

Venus

Earth

Asteroid 2013 TV135’s orbit, shown in blue, crosses those of the inner planets – but never takes it out past Jupiter

expect we will be able to significantly reduce, or rule out entirely, any impact probability for the foreseeable future.” http://www.crao.crimea.ua

AND NOW FOR THE ALIEN WEATHER...

Kepler 7b is 1.5 times the radius of fellow gas giant Jupiter

Looking back

COMET DEBRIS FOUND ON EARTH

A LARGE ASTEROID discovered in October by astronomers working at the Crimean Astrophysical Observatory in Ukraine made a close pass of Earth in mid-September, coming within 6.7 million km of our planet. The 400m rock, called 2013 TV135, could make another close approach in 2032, but early calculations by NASA scientists put the chances of the asteroid actually hitting Earth then at just one in 63,000. “This is a relatively new discovery,” says Don Yeomans from NASA’s Jet Propulsion Laboratory in California. “With more observations, I fully

Mercury

THE WEATHER ON extrasolar planets can be surprisingly predictable, say astronomers who have mapped the clouds on an exoplanet for the first time. They found that on any given day one side of a gas giant planet called Kepler 7b is heavily overcast, while the other enjoys clear, cloudless skies. Scientists hope to find out why the planet, which orbits a star nearly 1,000 lightyears away, has such a stark contrast in cloud cover. “Kepler 7b is an important test-bed for the way circulation and cloud distribution work together,” says team member Nikole Lewis from the Massachusetts Institute of Technology. www.nasa.gov/kepler

The Sky at Night November 1996 On 2 December 1968, the Sky at Night broadcast discussed the scorching planet Venus. Before the 1960s, many astronomers speculated that Venus had an Earth-like environment with lush vegetation underneath the thick clouds obscuring its surface – a view that was dispelled when the first space probes arrived to study the planet.

Earth’s ‘twin’ is an unbearably hot 462ºC

Both the Soviet Union and the US launched several missions to Venus, with NASA’s Mariner 2 making the first successful flyby in 1962. Observations gradually confirmed that Venus is hellishly hot; its average surface temperature is 462°C and its thick carbon-dioxide atmosphere is laced with clouds of poisonous sulphuric acid. Today, Venus is

much more of a known quantity, following detailed radar mapping of its surface by NASA’s Magellan spacecraft, launched in 1989, and long-term studies of the atmosphere by ESA’s Venus Express probe, which remains in orbit today.

skyatnightmagazine.com 2013

16

CUTTING EDGE

Our experts examine the hottest new research

The lost era of Venusian volcanism A global radar map of our planetary neighbour answers one question but throws up another WORDS: LEWIS DARTNELL Plains like this one cover nearly a fifth of Venus; each bright bump on it is a shield volcano

to certain volcanic features on Earth, such as the Siberian Traps. The regional plains cover about 40 per cent of Venus. Shield plains account for almost a fifth of the Venusian surface and are so named because are pimpled with numerous small volcanic mounds called ‘shields’. What Ivanov and Head found is whenever the regional plains and shield plains meet on the surface of Venus, it is the darker

NASA/JPL

I

n many ways, Venus is much like Earth: it is a rocky terrestrial planet that sports a significant atmosphere and is almost exactly the same size. And when it comes to sustaining widespread volcanic activity on a planetary body, size does matter – the crusts of the Moon and Mars cooled and thickened too quickly for widespread volcanism to have persisted for very long. So in terms of the evolution of volcanic and tectonic processes, Venus is the perfect place to study. But this ‘twin’ of ours has a few irksome quirks that frustrate our attempts to examine its past. For one, the thick cloud layers prevent us from seeing its surface using Earth-based telescopes or orbiting probes. Instead, we have to try and interpret radar maps. Even then, it’s nigh-on impossible to gauge how old the different landforms on Venus actually are. For the Moon or Mars we can use impact crater counting to work out how long a surface has been around for, but Venus exhibits so few craters that this technique is useless. The best you can do is work out whether neighbouring surfaces are relatively younger or older than one another – by noting which volcanic plain seems to have flown over the other, for example. With the completion of a radar-based topographical map covering the whole of Venus, Mikhail Ivanov of the Russian Academy of Sciences and James Head of Brown University in the US have been able to apply such geological detective work across the entire globe. Two of the most common land types on Venus are regional plains and shield plains. The former are large, smooth areas of solidified lava similar skyatnightmagazine.com 2013

“ The implication is that the dominant kind of volcanism changed at some point during Venus’s history”

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

regional plain that covers the other and seems to partially bury the shields. This indicates that the shield plains were present first and that the regional plains were formed more recently. The implication is that the dominant kind of volcanism changed at some point during Venus’s history, with the regional plains indicating an era of shortlived eruptions, which gushed out huge volumes of lava that spilled across of the surface. But while this extensive mapping and analysis study has contributed lots to our understanding of the relative ages of different landforms on Venus, there is still much we can’t see, such as where all the lava for the regional plains actually erupted from. There is still remains a great deal to unravel about this mysterious world.

LEWIS DARTNELL was reading… The history of volcanism on Venus by Mikhail A Ivanov and James W Head Read it online at http://www.sciencedirect.com/science/article/pii/S0032063313001098

BULLETIN DECEMBER 17

Huge black holes give up their secrets

News in brief

ALMA is clarifying the inner workings of their strange energetic jets

ROSETTA WAKES FROM DEEP SLEEP

< The unusual spiral structure near the centre

ALMA (ESO/NAOJ/NRAO)/NASA/ESA/F. COMBES, X-RAY: NASA/CXC/MSU/J.STRADER ET AL/OPTICAL: NASA/STSCI, ESA 2001. ILLUSTRATION BY MEDIALAB, NASA/JPL-CALTECH/SPACE SCIENCE INSTITUTE

of NGC 1433 is clearly defined in red and yellow

TWO SETS OF new observations have shed light on the long-standing mystery of the energetic jets that often sprout from opposite ends of supermassive black holes. Using the Atacama Large Millimeter/ Submillimeter Array (ALMA) researchers hope to gain new understanding of the role these jets have in shaping galaxy evolution. One team led by Françoise Combes from the Paris Observatory in France looked at how the relatively sedate jets in a galaxy called NGC 1433, which lies about 30 million lightyears away, interact with

surrounding molecular gas. They found an unexpected spiral structure where the gas was being dragged along by the jets. Studying this structure will help explain how the material is flowing in to fuel the black hole. The jet, or outflow, only extends for about 150 lightyears. “This is the smallest such molecular outflow ever observed in an external galaxy,” says Combes. Before ALMA, they would have never been able to observe it in this detail. A second team led by Ivan Martí-Vidal from the Onsala Space Observatory in Sweden looked at much more energetic jets in a distant galaxy called PKS 1830-211. They caught the central black hole swallowing a huge amount of matter, boosting the power of its jets to enormous energies. NASA’s Fermi Gamma-Ray Space Telescope also registered the flare-up, establishing clearly for the first time that both gamma rays and submillimetre radio waves come right from a jet’s base. “The new results, obtained even before ALMA was completed, show that it is a uniquely powerful tool for probing these jets,” concludes Martí-Vidal. “The discoveries are just beginning.” Supermassive black holes up to several billion times as massive as the Sun lurk at the hearts of almost all large galaxies. As matter swirls towards them due to their intense gravity, it heats to enormous temperatures and emits bright radiation. www.almaobservatory.org ELLIPTICAL GALAXY NGC 4649 – X-RAY & OPTICAL

SUPERDENSE GALAXY TEEMS WITH STARS A GALAXY JAM packed with stars has turned out to be the densest known galaxy in the nearby Universe. Jay Strader from Michigan State University and colleagues analysed observations of dwarf galaxy M60-UCD1, which lies 60 million lightyears away. Using NASA’s Chandra X-ray Observatory and ground-based telescopes, they found that it concentrates 100 million times the mass of our Sun within a radius of only about 80 lightyears, making the star density 15,000 times greater than in Earth’s neighbourhood in the Milky Way. www.nasa.gov/chandra

DWARF GALAXY M60-UCD1

In January, ESA’s cometchasing Rosetta probe will wake from hibernation. The spacecraft, launched in 2004, will activate its instruments in preparation for a rendezvous with comet 67P/ChuryumovGerasimenko in August 2014. The probe will map the comet and drop a lander onto its surface.

PLASTIC INGREDIENT FOUND ON TITAN NASA’s Cassini spacecraft has detected propylene – a chemical used to make plastic consumer products – on Saturn’s moon Titan. It marks the first time propylene has been found on any other planet or moon. Scientists have been looking for chemicals on Titan since NASA’s Voyager 1 spacecraft flew past the moon in 1980, revealing heavy and light members of the threecarbon family of hydrocarbons. But the middleweight chemicals, including propylene (C3H6 ), were missing. “This success boosts our confidence that we will find still more chemicals long hidden in Titan’s atmosphere,” says Michael Flasar from NASA’s Goddard Space Flight Center in Maryland.

OPTICAL

The star density in M60-UCD1 is 15,000 times greater than in our neighbourhood -meaning stars are 25 times closer

skyatnightmagazine.com 2013

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WHAT’S ON DECEMBER 19

What’s on

Our pick of the best events from around the UK

An Out of This World Christmas The National Space Centre, Leicester, 21-23 December, 10am to 6pm

PIFCTK HE

O TH MON

The Story of Jodrell Bank Augustine United Church, Edinburgh, 6 December 2013, 8pm Since its inception in 1945, the University of Manchester’s Jodrell Bank Observatory has been at the forefront of modern radio astronomy. Hear Jodrell astronomer Prof Ian Morison reveal the whole history of this world-famous institution at the Astronomical Society of Edinburgh on 6 December. For more information about this free talk, contact [email protected].

Swansea Christmas Lecture Swansea Waterfront Museum, 7 December, 2pm Andrew Lound, UK coordinator for the Planetary Society, returns to Swansea Astronomical Society to deliver this year’s Christmas Lecture. ‘Comets, signposts in history’ will explore the appearances of comets through time as stargazers study C/2012 S1 ISON post-perihelion. www.swanastro.org.uk/ public.php

Stop in on Santa and get hands-on in his workshop at this festive three-day event

KIERON ALLEN, JODRELL BANK/SCIENCE PHOTO LIBRARY, THINKSTOCK, KEV LOCHUN

Celebrate a cosmic Christmas with all the family at the National Space Centre this December. With a brass band playing Christmas songs, mulled wine (and non-alcoholic winterberry squash for the children), mince pies and a chance to meet the National Space Centre’s very own Father Christmas – complete with space elves – there’s no better way to get into the festive spirit. You can even join Santa in

his workshop and spend the afternoon creating your own Christmas decorations and space-themed stocking fillers. Of course, there will be a healthy dose of astronomy too with the centre’s galleries, exhibits and planetarium open all day. Adult tickets cost £10, with children’s tickets starting at £4. Booking is essential, as the centre will be closed to the public throughout the event. www.spacecentre.co.uk

BEHIND THE SCENES THE SKY AT NIGHT IN DECEMBER and

One, 1 December, around midnight (repeated Two, 7 December, midday)*

The Herschel Space Observatory Great Ellingham Recreation Centre, Great Ellingham, Norfolk, 13 December, 7.30pm After six years spent collecting observations from some of the most distant corners of the Universe, the Herschel Space Observatory was finally deactivated in June 2013. Hear Dr Chris North, the UK’s Herschel Outreach Officer, discuss the impact of the space scope’s findings at Breckland Astronomical Society this month. Tickets cost £2.50 per person. www.brecklandastro.org.uk

Four, 2 December, 8pm;

ON THE TAIL OF A COMET As comet C/2012 S1 ISON gets closer there is intense speculation about whether it will develop a beautiful tail or just break apart. On location on the Canary Island of La Palma, the Sky at Night team turn to the Liverpool and Isaac Newton Telescopes to go comet chasing. La Palma is home to wonderfully dark skies *Check www.radiotimes.com as times – as well as a number of professional scopes may vary

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

skyatnightmagazine.com 2013

20

diary Even when the cameras stop rolling, the show must – and does – go on. Paul Abel takes us into the uncharted realm that is the Sky at Night edit suite

BBC, PAUL ABEL X 3

I

t’s that time of year again, and I should start by wishing season’s greetings to you all! Christmas and New Year bring long, dark nights, equipment wishlists, endings and beginnings. It’s also a time to look back over the year; a year in which I hope I have brought you the feel of what it’s like to be involved in filming The Sky at Night. You’ve had a taste of the wonderful challenges supplied to us by the night sky and seen just how skillfully the programme is woven together. My thread for the November programme, which we’re recording as I write this, was filmed in September at the European Planetary Science Conference in London. This was something of a blessing: with the start of the new term at Leicester University well and truly upon me I had much to occupy my time in my role as a mathematics teaching fellow. Elsewhere, a penumbral lunar eclipse was due to occur on the night of 18-19 October. As you may know, a lunar eclipse occurs when the Moon passes into Earth’s shadow. In fact, this shadow is made of two regions, the dark black umbra, which is surrounded by a lighter penumbral region. When the Moon passes into this region, we have a penumbral eclipse. A lunar event like this was the perfect way of celebrating the results of our Moore Moon Marathon – an observing challenge devised by Pete Lawrence to

skyatnightmagazine.com 2013

< Sounding natural when ensconsed in a recording booth can be quite a challenge

þ Pete reviews the script ahead of his stint of ‘dubs’

explore the lunar surface. With these two objectives in mind, Chris Lintott, Lucie Green, Jon Culshaw and Pete went to Greenwich to record their segment of the November programme. Although the Moon doesn’t turn a dramatic dark red during a penumbral eclipse, it is nonetheless a nice subtle phenomenon to watch out for – my fellow presenters were joined in Greenwich by both the Flamsteed Astronomical Society and the Baker Street Irregulars. Alas, the forecast for the shoot was not good. The moody black clouds never did clear, although they thinned occasionally to allow fleeting glimpses of the Moon.

The team did succeed in presenting the results of the Moore Moon Marathon, however, showing that once more our viewers had taken on the challenge with great enthusiasm and skill, uploading their images to the programme’s Flickr site. Having a look at the collection, I was pleased to see not just detailed photographs, but also a

>

BEHIND THE SCENES DECEMBER 21

good selection of lunar drawings – being an avowed disciple of visual observing myself. Here in Leicester, I fared no better than the team in Greenwich: after a torrential downpour that any hurricane would be proud to produce, the sky cleared a fraction, although in the end, the only view of the Moon I had was that of a dimly glowing orb behind turbulent banks of angry clouds.

The mighty mixing desk, where each show is fashioned into its final form

Daunting David My next task for the November programme came after a busy teaching day, when I caught a train over to BBC Bristol to be ready for the next morning at 9am sharp – when Pete, Lucie and myself were recording a ‘dub’, as it called in broadcasting. A dub, which is a voiceover to everyone else, is an essential part of the programme: it helps one scene move smoothly to the next, neatly summing up the key points in the transition to the next location. Not only that, it also allows us to narrate over images and video demonstrations. I remember the first dub I ever did at BBC Bristol, simply because the chap in charge of the audio told me that David Attenborough had been in that

viewing screen at the end and the banks of switches and buttons, looks like the bridge of a spacecraft.

Going it alone Recording a dub has some unexpected challenges: there is only your voice to convey the meaning, no other colleagues to build an on-screen rapport with, so you have to be as enthusiastic as possible – but at the same time, avoid sounding like you’ve overdone it on the espressos. The dubs are recorded in time to the relevant

“David Attenborough had been in that very chair only an hour or so before me – no pressure then!” very chair only an hour or so before me – no pressure then! The voiceovers are recorded at a sound studio somewhere deep in the heart of BBC Bristol – I’m not being deliberately mysterious, I genuinely do get lost in the place! The studio consists of two rooms: a sound booth, which contains the microphone, a comfy chair and table to rest the script on, and the mixing room, where the speakers’ voices are recorded and the sound levels are controlled. I always think that the studio, with its large

scene from the programme, which plays on the viewing screen. Naturally, there are times when a piece doesn’t sound right. The problem could be that a take might sound a little flat, so over the headphones will come the request for more emphasis and liveliness in the delivery. Sometimes the dub might be too long for the segment, or it might not flow properly and need rewriting. Often a number of takes are done in different styles, which have to match the imagery that it will be heard over. For me, recording the dubs is very enjoyable – it’s good fun getting the piece

just right in the time that’s allocated for it. With it, all the recordings were in the bag and were sent to the Sky at Night’s editor, who layered it into the programme. As we left Bristol that afternoon with the editor adding the finishing touches, November’s show was almost ready to go. December’s programme promises to be a real treat for viewers. Chris Lintott, Chris North, Pete and myself will be using the Isaac Newton and Liverpool Telescopes, which are situated high up on the island of La Palma. I’m rather looking forward to seeing some of the observatories that populate the mountain slopes of this exotic place. And this time, with the island’s favourable climate and the altitude of the telescopes, we are bound to have clear skies! S

THE SKY AT NIGHT IN DECEMBER One, 1 December, around midnight (repeated Four, 2 December, 8pm; and Two, 7 December, midday)*

ON THE TAIL OF A COMET With intense speculation as to whether comet C/2012 S1 ISON will develop a beautiful tail or just break apart, the Sky at Night team head to the Canary Island of La Palma, using the Liverpool and Isaac Newton Telescopes to go comet chasing. *Check www.radiotimes.com as times may vary

skyatnightmagazine.com 2013

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EXOPLANET EXCURSIONS DECEMBER 23

MAIN ILLUSTRATION BY MARK GARLICK, PHOTO: EMMA SAMMS

Our new columnist’s off-world travelogue kicks off with a trip to our nearest star system TODAY WE ARE living though a deliciously effervescent period of discovery – a new and beautifully alien exoplanet being discovered almost weekly. What once seemed unreachable is drawing closer to us. So, each month in our Exoplanet Excursions I shall bring these exotic other worlds to life as our human senses might perceive them, imagining such alien experiences as what it would feel like to watch four suns of varying hues set after a blizzard of raining glass. The results will be entered in a travelogue, much as Judith Chalmers did with Bratislava and Lanzarote. On our first excursion, it seems reasonable to visit the neighbour, the Alpha Centauri system. At 4.37 lightyears away, we could just about get there in the time between two football World Cups – once we’ve mastered lightspeed travel, at least. I’m here to visit the chirpily named exoplanet Alpha Centauri Bb, discovered on 12 October 2012 using Doppler spectroscopy. Yes it sounds like a band John Peel would have introduced, but this technique found a world

similar in size to Earth, orbiting an extremely close 0.04 AU to the star Alpha Centauri B. Good gracious, Alpha Centauri Bb is an absolute vision of hell, but what would you expect from a world 25 times closer to its star than Earth is to the Sun? Safe inside my Pyrex Cruiser Globe*, with my heat force-field settings turned up to maximum, there’s a comfortable and utterly mesmerising view over this tidally locked planet and the star it orbits. It’s beyond profound. A star, hanging in this alien sky, 22 times larger than our Sun and an incredible 300 times brighter. I set the reactolight filters on the cruiser globe to 60 per cent power to shield the glare and take in the view. This deep orange star and the deep orange lava on Alpha Centauri Bb’s surface blend like an ocean-sized infinity pool of molten tomato soup. There’s a steadfast sense of dependability in how Alpha Centauri B hangs in the sky of this tidally locked planet. It’s confusing and downright odd to have no way of perceiving time from a star that never moves – frankly I don’t know when to have breakfast.

Steering the Pyrex Cruiser Globe into reverse now, I head for the terminator and come to rest where we see just the top quarter of the star. It’s a perpetual, horizon-filling sunset – a sunset with the pause button pressed, and it’s easier to feel peaceful and more reflective in this zone. Reversing further to Alpha Centauri Bb’s constant dark side brings welcome reminders of Earth’s night sky with some familiar constellations. But wait – Cassiopeia has an intriguing extra point of light within it. With a pang of affection I realise that this is none other than our own Sun! Good on our dear old plucky star for gatecrashing Cassiopeia and turning it from the W we all know into something that looks more like a 1950s pram. Well, this feels the moment to depart Alpha Centauri for our next Exoplanet Excursion. Farther next time? Much, much farther. *Technology described is yet to be invented. Just go with it! Jon Culshaw is a comedian, impressionist and regular guest on The Sky at Night

24

Interactive EMAILS s LETTERS s TWEETS

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 An asterism hunter after our own heart After after a stormy night on 28 October, I was looking up at a clear night sky with my son and daughter. We scanned the Autumn asterism of the Great Square of Pegasus and I helped my son pick out the Andromeda Galaxy. Then we had another look at the Northern Cross asterism in Cygnus and spent some time on the asterism’s bottom star, Albireo: I love looking at this double star and splitting it into its two distinct colours. Then we ‘hung our coats’ on the Coathanger asterism in Vulpecula. All of a sudden my daughter asked me what I thought of the Heart asterism. “The what?” I asked her. “The Heart Asterism,” she said. “Look daddy, around

Deneb. There it is!” I grabbed the 10x50 binoculars, and yes: there, around Deneb at the top of the Northern Cross in Cygnus, was the Heart asterism! And at the request of a keen 10-year-old amateur astronomer, with a better eye and more appreciation of the night sky than me, I’m sharing her discovery with you. Many thanks to you for making our night watches even more fun, and keeping us up to date. Dean James, via email Deneb sits at the centre of the freshly discovered Heart asterism

Hampstead heroes

þ Doug and Julia celebrate with Sky at Night presenters Paul Abel and Jon Culshaw

skyatnightmagazine.com 2013

My wife Julia and I have just about recovered from the shock of being presented with BBC Sky at Night Magazine’s award for our contribution to astronomy. The presentation came as a total surprise to us and, what with the heat of the day, we found it somewhat overwhelming. I only hope that I thanked everyone adequately on the day. However, I would now like to take this opportunity to thank you for the presentation and the lovely article in the October edition of the magazine (page 72). As I hope I expressed at the time, Julia and I are proud to receive this award, but we are just very fortunate to have a great team of

What a heart-warming story, Dean, and a great reward for showing your kids the night sky. Well spotted by your daughter! – Ed

enthusiasts with us who are willing to devote their time to continuing to introduce members of the public to the ‘pleasures of the telescope’ and the wonders of the Universe. We are proud of our observatory, which as been performing this task for 105 years! We derive great satisfaction each year when we recruit and perhaps inspire young students who are taking their first steps in careers in the physical sciences, and who will go on to further their studies at university; this year one of our assistants will be reading mathematics at Oxford. Nevertheless, it is very nice to know that our small contribution was considered worthy of recognition by our peers, for which we are truly grateful. Thank you BBC Sky at Night Magazine. Doug & Julia Daniels, Hampstead Scientific Society, London

It was a privilege to recognise the great contribution you have made to amateur astronomy, Doug and Julia. – Ed

LETTERS DECEMBER 25

Vexing Voyager

The big debate Have your say at http://twitter.com/ skyatnightmag @skyatnightmag asked: Which celestial event are you most looking forward to in 2014? @gazsc Perseids in August 2014. Had great fun viewing them this year. @PatrickPoitevin I’m looking forward to the International Solar Eclipse Conference SEC2014 in New Mexico 23-26 Oct. @khargaoasis May 10th, Saturn at opposition, closest approach to Earth – will try to photograph it! @BikeBoxOnline Re-runs of Stars in your Eyes ;) @ParrGordonparr Neptune at opposition, I’ll use my telescope to see it for the first time. @Derekscope Moon occults Mercury on 26 Oct, I want to try seeing that in the daylight at 11:50am & the Moon occults Saturn on 25 Oct. @nickdud That cloudless weekend sometime in mid March when I can get my scope out.

I read with interest Chris Lintott’s Comment on Voyager 1’s journey so far and the associated article by Hazel Muir (November 2013, page 11). In other articles I have read on Voyager 1, I’ve noticed some curious discrepancies that make the timescales very confusing. For example in one article, the speed the probe is currently travelling is given as approximately 28 miles per second (45 km/s) – about 6,650 times slower than the speed of light. If the Sun’s gravitational influence extends for approximately one lightyear then it would take Voyager 1 – at current speeds – 6,650 years to reach that point and 30,000 years to reach our nearest star, Proxima Centauri. These figures would appear to be at considerable variance to those given by Chris Lintott. He is suggesting that it would take Voyager 30,000 years just to pass through the Oort Cloud alone. I do wonder if that shouldn’t be 3,000 years? I really should be most grateful for some clarification for these differences and what may be considered to be the more accurate assessment. David N Kidd, Southampton

READERS’ SCOPES My Meade ETX80 Backpack is a truly portable telescope. It’s usually is thrown (gently) into the car boot every other Wednesday for the Bassetlaw Astronomical Society meetings. If there is any chance of a clear sky it is quickly assembled during the coffee break for viewing. The entire telescope – apart from the tripod and an additional white groundsheet, which is an essential way of not losing bits and pieces in the grass – fits into the supplied backpack. On our recent holiday to Lake Viñuela in Andalusia, the ETX80 went through security as hand luggage with little fuss, while the tripod went in the hold luggage. My wife bought me the telescope for my 50th birthday earlier this year, and it was fantastic to use it on really clear skies with almost no light pollution. David Wilson, via email

NASA currently measures Voyager 1’s speed as 3.6 AU per year, which is about 10.5 miles per second (17km/s), slower than given in the article you reference. Current thinking on the size of the Oort Cloud is that it extends out to a minimum of 50,000AU from the Sun. So at current speeds Voyager 1 would take at least 14,000 years to traverse it, longer if this theoretical cloud is bigger. Our nearest star, Proxima Centauri, is 4.24 lightyears away, and it would take Voyager 1 over 250,000 years to travel that distance. – Ed

what kind of telescope design you’d be most interested in making. – Ed

An Englishman abroad

RegiStax the rascal

As an Englishman living in America, I have BBC Sky at Night Magazine sent over to me here in Florida, and I look forward to it as my taste and experience of England once a month as well as what it does to enhance my enjoyment of astronomy. Your magazine is excellent at balancing articles for beginners with data that more advanced astronomers appreciate. One of the great problems in astronomy is caused by partially understood or misunderstood words in the subject, which newcomers don’t have cleared up for them. They then don’t have a full understanding of the subject and lose interest. Your magazine cuts through all that by really explaining things well and not assuming the reader is an astrophysicist! I hope you will carry on with the great articles on binocular astronomy and well-explained practical sections. Will there be any articles on how to make a telescope too?

In your review of the Celestron NexImage5 CCD camera (September 2013, page 98) you suggested that AVIs of 5GB up to 20GB were processed through RegiStax 6. I find if I try to process an AVI that is over 1GB in size RegiStax refuses to accept it, even if it is ticked to accept AVIs over 2GB. Did you have any problems with large AVIs when carrying out the review?

Paul Lewis, Florida, US

I’m delighted that we fulfil your need for a slice of astronomy and home, Paul. We would be interested to know from you and other readers

Tell us about your scope! Email [email protected]

Graham Leaver, Kirkby-in-Ashfield

RegiStax can sometimes be troublesome when it comes to large files sizes over 1GB. One way to overcome this is to first run the file through Pipp (https://sites.google.com/site/astropipp/) to pick the best frames. This will then reduce the file size prior to using RegiStax. – Martin Lewis

A fitting tribute On 28 September 2013 I attended the Patrick@Night event held at the National Space Centre in Leicester to celebrate the life and contributions to astronomy made by Sir Patrick Moore. It really was a very enjoyable evening, which felt more like a gathering of friends than a public event. As well as some skyatnightmagazine.com 2013

26 LETTERS DECEMBER

The big debate @jowlymonster Hoping to get a Northern Lights trip in. Also, Comet Siding Spring could be interesting. @Spacemouse77 With the Sun’s polar reverse coming up, I’m looking forward to some hopefully awesome aurorae from Scotland at the beginning of 2014. @DavidBflower The conjunction of Venus and Jupiter in August, to see the brightest and largest planets so close together will be amazing! @andy_ledger Jupiter at opposition – moon transits, changes to the cloud belts, GRS hunting – it’s an astro happy meal!

wonderful xylophone compositions filling the air, an eagerly awaited unveiling of a bust of Sir Patrick also took place, which was met with great approval. The Sky at Night presenters all did an excellent job of meeting and greeting their fans; Jon Culshaw paid a fond farewell in astronomical verse, which raised many a chuckle! It really was a fitting tribute to a larger than life character who will be missed, but never forgotten. As my own small tribute I have produced a mosaic image of Sir Patrick. Andrew Richens, Long Sutton, Lincolnshire

A very inventive tribute, Andrew. Read our report of the Patrick@Night event on page 13. – Ed

EDITORIAL Editor Chris Bramley Production Editor Kev Lochun Online Editor Kieron Allen Staff Writer Elizabeth Pearson Reviews Editor Paul Money ART AND PICTURES Art Editor Steve Marsh Picture Research Sarah Kennett CONTRIBUTORS Paul Abel, Ade Ashford, Adam Crute, Jon Culshaw, Lewis Dartnell, Glenn Dawes, Ray Emery, Mark Garlick, Will Gater, Alastair Gunn, Carol Lakomiak, Pete Lawrence, Chris Lintott, Hazel Muir, Chris North, Mark Parrish, Mark Payne-Gill, Steve Richards, Steve Sayers, Paul Sutherland, Stephen Tonkin, Vincent Whiteman, 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)

Þ Andrew’s mosaic recreates an iconic image of Patrick

Spiky stowaways On a few separate occasions when I’ve been in my observatory, I’ve heard a strange scrabbling sound outside. On investigation, I discovered that I had a nocturnal visitor in the shape of a hedgehog, whom I named Spike (I know, not very original). Then, one Saturday evening I went out to my observatory with the intention of checking the polar alignment of my mount, and when I opened the door I noticed an odd smell. I also saw the floor was strewn with pieces of a plastic bag that looked like it had been through a shredder. The reason: you guessed it, Spike! There he was curled up on the box I keep my PST solarscope in. I can only assume that he had crept in the last time I was in the observatory on the Wednesday previously, and had been locked inside for three days! I carefully shooed him out and he went on his way, hopefully none the worse for his ordeal. So if you have an observatory, before locking up I would suggest you check carefully in case Spike is paying you a visit.

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I can imagine your surprise, James! If Spike pays you another visit, you could consider making a shelter for him outside the observatory by placing a piece of board against one of the walls. – Ed

© Immediate Media Company Bristol Limited 2013 ISSN 1745-9869

......................................................................................... OOPS! s)NTHE/CTOBERISSUE THEJUDGESVERDICTFORTHE Best Newcomer image in the Astronomy Photographer of the Year 2013 feature should have come from Melanie Vandenbrouck and read: “Anticipation is palpable in this picture. I like the sense of mystery in the way the Sun appears behind the clouds and Venus gracefully appears on the edge of the solar disc.”

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Sky at Night MAGAZINE

30

Hotshots

This month’s pick of your very best astrophotos

PHOTO OF THE

MONTH

S Aurora borealis STEWART WATT, LOCH CALDER, SCOTLAND, 31 AUGUST 2013 Stewart says: “What I like about this shot is the natural framing provided by the location and the way the aurora illuminates the calm waters of the loch. The dark surrounds of the Moonless night sky seem to intensify the brightness of the aurora and channel it down the loch straight to the camera.” Equipment: Canon EOS 5D Mk III DSLR camera, Samyang 14mm f2.8 lens.

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BBC Sky at Night Magazine says: “Stewart has managed to capture the vivid colours of the aurora borealis in exquisite detail. The ghoulish green glow of the loch and the star field above it frame the lights of the aurora in this beautifully composed shot.” About Stewart: “Thanks to the Apollo programme, my interest in astronomy started when I was at primary school in Stromness,

Orkney, and it has stayed with me ever since. Nowadays I live in Thurso, Caithness, where we’re blessed with some of the darkest skies in the UK. I started taking photographs about four years ago. My only regret is that I didn’t start years earlier, as I missed the opportunity to capture some of the fantastic overhead aurorae of previous solar maximums.”

HOTSHOTS DECEMBER 31

The Triangulum Galaxy X MATT FOYLE, DERBYSHIRE 3, 9 AND 14 SEPTEMBER 2013 Matt says: “This is my attempt at M33, the Triangulum Galaxy. I had planned to image this object at f/8 for around 30 hours, but due to the weather I could only get 13 hours.” Equipment: QHY9M CCD camera, Takahashi FSQ-106ED refractor, Sky-Watcher NEQ6 PRO mount.

W The Sun JOHN CHUMACK OHIO, US 19 AUGUST 2013 John says: “I took some quick shots and managed to capture lots of sunspots, active regions and a huge filament too.” Equipment: DMK31 CCD camera, Lunt 2.5-inch hydrogenalpha telescope.

The Horsehead and Flame Nebulae, plus Alnitak X TONY SUMA-HAWES, QUEENSLAND, AUSTRALIA, 10 AUGUST 2013 Tony says: “I took five, five-minute sub-frames of this region before accidentally leaving the aperture open for 22 minutes. I expected to have overexposed it, but instead found the shot added a great deal of colour and detail.” Equipment: Modified Canon EOS 450D DSLR camera, William Optics 4.5-inch Megrez apo refractor, Sky-Watcher NEQ6 mount.

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32 HOTSHOTS DECEMBER

T Ursa Major and Ursa Minor '/2$/.-!#+)% 4(523/ 3#/4,!.$ 3%04%-"%2 Gordon says: “Although I have many pictures from this spot, this photo – with its simplicity – is one of my favourites. And what sophisticated equipment did I use? A DSLR and a standard photographic tripod. Who says astro imaging needs to be complicated.” Equipment: Canon EOS 650D DSLR camera.

S The North America and Pelican Nebulae PETER VASEY, HEXHAM, NORTHUMBERLAND 3%04%-"%2 Peter says: h/NTHECLEARNIGHTOF3EPTEMBER)DECIDED to image this area wide-field using a camera lens and was amazed to see just how much showed up!” Equipment: 13)COOLED##$CAMERA #ANON 200mm f/4 L lens.

W Full Moon BOB HOLDER, DEAL, KENT, 20 AUGUST 2013 Bob says: “I snapped this picture on a recent visit to the seaside town of Deal. I had planned the composition to include the old street lamp and the Moon but a seagull flew into frame just as I took the shot. I was both lucky and chuffed!” Equipment: Canon EOS 20D DSLR camera, Sigma 120-400mm lens.

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

WORTH

£99

skyatnightmagazine.com 2013

WWWWIDESCREEN CENTRECOUKs

OBSERVING CHALLENGE DECEMBER 35

TheCaldwell T challenge Steve Richards selects 15 of his favourite Caldwell objects for a very special observing tour

he long December nights are ideal for discovery, something Patrick Moore, our late editor emeritus, was keen to encourage. To celebrate that we’ve put together a special observing challenge based on Patrick’s very own Caldwell Catalogue: we’ve picked out 15 of our favourite objects from his list that are visible this month – your task is to find them all in a single observing session. Some of these are quite popular, appearing in our deep-sky and binocular tours from time to time; others are a bit lesser known. Hopefully you’ll be discovering some of these for the first time. The minimum size telescope for this challenge is a 4-inch refractor – all the objects in this challenge are within reach of this instrument under dark skies. Larger apertures will certainly help though, revealing hidden details that may otherwise elude you. We would suggest that you attempt the challenge early in the month to avoid interference from the Moon. A couple of days either side of 5 December from about 21:00 UT would be a good goal if the clouds play fair. As it is winter, be sure to wear suitable warm clothing and have some hot drinks on hand. Why not involve some friends and their telescopes in the challenge and make this a social occasion too? >

THINKSTOCK

PATRICK’S CATALOGUE

The North America Nebula is one of the most impressive objects in Patrick’s list

The Caldwell Catalogue came about because Patrick felt that the Messier Catalogue – a list of objects that comet hunters should avoid – was somewhat incomplete. So he drew up a list of his own favourite objects, all absent from Messier’s magnum opus. With the ‘M’ of Moore already taken, Patrick opted to use the ‘C’ of Caldwell for the objects in his list – his full surname was of course Caldwell-Moore. Patrick’s catalogue contains 109 objects, but unlike Messier’s they are spread across both the northern and southern hemispheres. It includes 28 open clusters, 18 globulars, 35 galaxies, 13 planetary nebulae, 12 bright nebulae, one dark nebula and two supernova remnants, arranged in order of declination.

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36

ANDROMEDA

PISCES

LACERTA

a

_ M31

`

`

M33

Mirach

IC 1396

Hamal

Metallah

_

_

1

NGC 752

CASSIOPEIA

_

Caph

_

`

` Schedar

a TRIANGULUM

Almach

a

a q

2

4

NGC 457 Ruchbah

`

M34

NGC 869

CEPHEUS

Algol

3 Segin Errai

ARIES

NGC 891

o

`

NGC 884

a _

a

Melotte 20

Mirphak

URSA MINOR

5

NGC 188

CAMELOPARDALIS

PERSEUS

NGC 1499

Polaris

CHART BY PETE LAWRENCE, JOHN CHUMACK/SCIENCE PHOTO LIBRARY NOAO/AURA/NSF, THINKSTOCK

5 DECEMBER, 21:00 UT

1. NGC 752 Also designated: C28 RA 01h 57m 48s, dec. 37° 41’ 00”

We start our challenge with a fine binocular object originally discovered by Caroline Herschel in 1783. Open cluster C28, also known as NGC 752, lies one-third of the way between mag. +2.3 Almach (Gamma (a) Andromedae) and the apex star in the constellation of Triangulum, mag. +3.4 Metallah (Alpha (_) Trianguli). It can be easily found by sweeping between the two stars and, at almost two billion years old, this is one of the oldest star clusters known. Binoculars will show in the region of 30 widely scattered stars, although a rich-field telescope at low magnification is the best way to really enjoy this lovely object, revealing in excess of 60 individual skyatnightmagazine.com 2013

member stars, more than a dozen of which are brighter than mag. +10.0.  SEEN IT

2. NGC 891 Also designated: C23 RA 02h 22m 36s, dec. 42° 21’ 00”

Moving nearly 7° northeast now, your second object lies one-third of the way along a line joining the stars Almach and mag. +2.1 Algol (Beta (`) Persei). We’re looking for mag. +9.9 edgeon galaxy NGC 891, and although it is visible in a 4-inch telescope its low surface brightness means you may need to use averted vision. It is worth lingering here a little as more and more detail will be revealed as your eye becomes accustomed to the view. If you can increase your aperture and up the magnification to around 120x, with careful scrutiny you

should discern a slender dark dust lane bisecting the galaxy. This object too was originally discovered by Caroline Herschel in 1784 and it is believed to be over 30 million lightyears away from us.  SEEN IT

3. The Double Cluster Also designated: C14; NGC 869 & NGC 884 RA 02h 19m 00s, dec. 57° 09’ 00”

Continuing our journey into Perseus, your next target is a real treat, two objects for the price of one! NGC 869 and NGC 884 are popularly known as the Double Cluster today; in antiquity it was the Sword Handle, referencing the jewel-encrusted sword given to Perseus by Athena and Hermes to help him behead the Gorgon Medusa; the latter is represented by the star Algol. The individual clusters are a fine sight through

OBSERVING CHALLENGE DECEMBER 37

Þ It was looking at this object, the Double Cluster in Perseus, that inspired Patrick Moore to put together his observing catalogue in the first place binoculars and can be seen with the naked eye from a dark location. A binocular sweep between mag. +3.9 Tau (o) Persei and mag. +2.7 Ruchbah (Delta (b) Cassiopeiae) will easily find them. NGC 884, the more easterly of the two, contains numerous white-blue stars, whereas NGC 869 is dimmer and more compact.  SEEN IT

4. The Owl Cluster Also designated: C13; NGC 457 RA 01h 19m 06s, dec. 58° 20’ 00”

We leave Perseus and continue into Cassiopeia, a constellation named after a queen who vainly boasted of her unrivalled beauty. There is real beauty here though with the aptly named Owl Cluster – although it is also sometimes referred to as the ET Cluster because its

< A slender dust lane slices through edge-on spiral galaxy NGC 891

shape has been said to resemble the alien from the film of the same name. The brightest star visible in the cluster is one of the owl’s eyes, mag. +5.0 Phi (q) Cassiopeiae. It lies 2° to the southwest of Ruchbah, so it is quite easy to find. In truth, bright red Phi Cassiopeiae is not actually a member of the cluster at all, but a foreground star. All the same, it certainly adds to the view through binoculars or a small scope.  SEEN IT

of the Pole Star, Polaris, open cluster NGC 188 is often ignored by observers with equatorial mounts as locating objects this close to the pole can be a bit fiddly. But what’s an observing challenge without a bit of challenge? Unusually for an open cluster, this one comprises many older stars, more yellow than the hot white young stars that you might have expected. With a magnitude of +8.1, it’s not a nakedeye object, but a 4-inch telescope at 30x magnification will reveal it as a stretched scattering of stars set against a brighter circular core.  SEEN IT >

5. NGC 188 Also designated: C1 RA 00h 44m 00s, dec. 85° 20’ 00”

Once you tick off this next object you’ll be one-third of the way through the challenge. Located just 4° to the south

Þ NGC 188 is home to a large number of yellow stars, quite unusual for an open cluster skyatnightmagazine.com 2013

38

_

Caph

`

ANDROMEDA

a M52

NGC 188

Errai

10 NGC 7662

CEPHEUS

k Alfirk

_

`

LACERTA

`

NGC 7023 Alderamin

8

IC 5146

6

_

/2

/1

IC 1396

d

7

B168 M39

NGC 6946

PEGASUS

NGC 7000

`

9

NGC 6996

DRACO

Deneb

CYGNUS

_

NGC 6997

k2 k1

a

Sadr

Veil Nebula Complex

5 DECEMBER, 21:00 UT

6. The Iris Nebula CHART BY PETE LAWRENCE, THINKSTOCK X 2, ADAM BLOCK/SCIENCE PHOTO LIBRARY

Also designated: C4; NGC 7023 RA 21h 00m 30s, dec. 68° 10’ 00”

Þ The Iris Nebula is lit up from within by the binary star at its heart, HD 200775 skyatnightmagazine.com 2013

Now’s a good time to take a break and warm up with a hot drink as you prepare for the second stint, which starts with the Iris Nebula. This bright reflection nebula sits in an area of sky strewn with dust and is an old favourite with astrophotographers. Locate it 3.3° southwest of mag. +3.2 Alfirk (Beta (`) Cephei) – you’ll need a large telescope to see it well. There is a star cluster associated with the nebula (Collinder 427) but the Caldwell designation purely refers to the nebula. William Herschel discovered the nebula on 18 October 1794 describing it as “a star, seventh magnitude very much affected with nebulosity”. This star is mag. +7.3 HD 200775, a close binary that

illuminates the dust surrounding it to give the Iris Nebula its shape.  SEEN IT

7. The Fireworks Galaxy Also designated: C12; NGC 6946 RA 20h 34m 48s, dec. 60° 09’ 00”

We’re moving southwest now, just into Cygnus for our next object. The Fireworks Galaxy is a face-on spiral that lies just over 2° southwest of mag. +3.4 Eta (d) Cephei. Although the galaxy has an apparent magnitude of +8.9, its relative brightness is spread over a wide area, so it appears dimmer than you might expect despite its common name! This situation is not helped by the galaxy’s close proximity to the Milky Way’s galactic plane, which also obscures some of its light. The core of the Fireworks Galaxy is visible in a 4-inch telescope, but to discern

OBSERVING CHALLENGE DECEMBER 39

Þ The path ‘carved out’ by the Cocoon Nebula is clearly visible here; the truth is that the trail is actually a dark nebula, the eerie Barnard 168 its spiral arms you’ll need a 10-inch aperture at least. The galaxy is also something of a supernova hotspot, with eight having been counted since 1917 – fireworks indeed.  SEEN IT

8. The Cocoon Nebula Also designated: C19; IC 5146 RA 21h 53m 24s, dec. 47° 16’ 00”

Remaining in Cygnus, our next stop is the fascinating Cocoon Nebula. In photographs this almost circular emission nebula appears to have carved a path through the stars but this is just an illusion! The nebula’s location just happens to coincide with the eastern edge of a fine example of dark nebulosity, Barnard 168. This dark lane of lightabsorbing dust can be easily spotted through a pair of binoculars as it meanders its way across the sky. To locate the nebula, sweep 2.3° southeast of mag. +4.3 Pi 2 (π2) Cygni. A 4-inch telescope will show the nebula as a hazy circular patch, but a 10-inch or larger instrument with either a hydrogenbeta or ultra-high contrast filter will offer an improved view, cutting down the light from two bright embedded stars.  SEEN IT

9. The North America Nebula Also designated: C20; NGC 7000 RA 20h 58m 48s, dec. 44° 20’ 00”

10. The Blue Snowball Also designated: C22; NGC 7662 RA 23h 25m 54s, dec. 42° 33’ 00”

Time for another constellation and a very different object A trip around Cygnus wouldn’t indeed. Planetary nebulae form when be complete without a visit old stars are no longer able to to the North America Nebula. support fusion at their cores On a crisp, clear night, the and they start to collapse nebula can just be seen in on themselves. The with the naked eye as a high core temperature rich area of nebulosity. generated by this For imagers this is drives the outer gas an ideal object for layers away; the core’s hydrogen-alpha energy causes the now filtering, but for distant gas clouds to observing binoculars glow. One such nebula is or a 4-inch telescope at the beautiful Blue Snowball very low magnification in which ultraviolet light are the instruments of from the hot core has excited the choice. If you have access to a Þ Ionised oxygen surrounding gas molecules and larger scope however, it is well gives the Blue the strong emission from ionised worth seeking out open clusters Snowball its hue oxygen produces a gorgeous bluish NGC 6996 and NGC 6997, which hue. Through a small telescope, the nebula are embedded within the nebulosity. Find looks like a fuzzy star, but a larger scope will the nebula by imagining a line from mag. resolve the disc and the darker central +3.8 Omicron1 (k1) Cygni through mag. +1.3 Deneb (Alpha (_) Cygni), then extend region. The nebula lies 4.5° east of mag. +3.6 Omicron (k) Andromedae.  SEEN IT > it half as much again.  SEEN IT skyatnightmagazine.com 2013

40

CAMELOPARDALIS

Capella

NGC 2403

AURIGA

_

11

Collinder 62

TAURUS

Hassaleh

14 f IC 405

`

M38

Muscida

_ M36

k

`

M37

Elnath

URSA MAJOR

Collinder 65 Berkeley 21

LYNX Talitha

M35

12

GEMINI

NGC 2419

f

Collinder 69

Castor

_ _

a

Pollux

` b

Wasat

ORION

Alhena

Jupiter

Betelgeuse

NGC 2264

Alzirr

j CANCER

_

NGC 2392

13

15 NGC 2261

MONOCEROS

5 DECEMBER, 21:00 UT

(Omicron (k) Ursae Majoris). A 4-inch telescope will show an elongated hazy patch but you’ll need a 12-inch telescope to view the spiral arms.  SEEN IT

11. NGC 2403

CHART BY PETE LAWRENCE, GREGG RUPPEL, STEVE RICHARDS, RUSSELL CROMAN/SCIENCE PHOTO LIBRARY

Also designated: C7 RA 07h 36m 54s, dec. 65° 36’ 00”

We’re two-thirds of the way through now so it’s definitely time for another drink and warmup. Our first object in the final stint is spiral galaxy NGC 2403 in Camelopardalis. It has an appearance very similar to that of the Triangulam Galaxy, with numerous HII star-forming regions within its two layers of spiral arms. Shining at mag. +8.4, this is one of the brightest galaxies in the sky – but again like the Triangulam Galaxy, it is large and that brightness is spread out. NGC 2403 is somewhat isolated in sparsely populated Camelopardalis. You can find it just under 8° northwest of mag. +3.3 Muscida skyatnightmagazine.com 2013

NGC 2237

12. The Intergalactic Wanderer Also designated: C25; NGC 2419 RA 07h 38m 06s, dec. 38° 53’ 00”

Þ Spiral-armed NGC 2403 bears a passing resemblance to M33, the Triangulam Galaxy

A quick hop southwards into Lynx will take us to a distant globular cluster known as the Intergalactic Wanderer, as it was originally believed to be located outside the gravitational influence of the Milky Way – something we now know to be untrue. Discovered by William Herschel in December 1788, this cluster is one the remotest globulars ever found, at a distance of 182,000 lightyears. Look

OBSERVING CHALLENGE DECEMBER 41 for it 7° to the north of mag. +1.6 Castor (Alpha (_) Geminorum). It’s a difficult object in a 4-inch telescope, but a 10-inch or larger will reveal its condensed core and patchy halo.  SEEN IT

13. The Eskimo Nebula Also designated: C39; NGC 2392 RA 07h 29m 12s, dec. 20° 55’ 00”

We continue our journey south into Gemini, sweeping past Castor and onwards to a point 2.4° southeast of mag. +3.5 Wasat (Delta (b) Geminorum) to find our second planetary nebula. As if to underline the cold of this December night, we are visiting NGC 2392, the Eskimo Nebula. Although visible through a 4-inch telescope, with a diameter of only 15 arcseconds you’ll need at least a 6-inch telescope to show the shape of the Eskimo’s ‘face’ and the ‘furry hood’ that surrounds it. A 10inch or larger instrument will reveal a host of other delicate details, including two distinct shells – a bright inner mottled region with an outer faint halo separated by a dark ring. The nebula’s very distinctive appearance wasn’t lost on William Herschel who described it as “a very remarkable phenomenon” when he discovered it in 1787.  SEEN IT

14. The Flaming Star Nebula Also designated: C31; IC 405 RA 05h 16m 12s, dec. 34° 16’ 00”

Although our next object is an astrophotographer’s dream, it is more challenging for observers. The Flaming Star Nebula lies 4.2° east northeast of mag. +2.7 Hassaleh The Intergalactic Wanderer is one the most distant globulars we know of

Þ A challenging spot, the Flaming Star Nebula contains both emission and reflection nebulosity (Iota (f) Aurigae) and is a delightful mix of both reflection and emission nebulosity. The star responsible for generating all the energy is HD 34078, which can be clearly seen at the heart of the nebula. However, this star is here by chance: it’s just passing through on its long journey away from a cataclysmic interaction with the Trapezium stars in the Orion Nebula in the distant past. The roughly triangular shape of the nebula can be discerned through a 6-inch or larger telescope, but HD 34078 dominates the view. Try fitting a hydrogen-beta filter to your scope to tame the star.  SEEN IT

15. Hubble’s Variable Nebula Also designated: C46; NGC 2261 RA 06h 39m 12s, dec. 08° 44’ 00”

Congratulations, you have reached the final object, the enigmatic cometshaped nebula NGC 2261, also known as Hubble’s Variable Nebula from a series of images captured by Edwin Hubble in January 1949. The nebula changes in brightness and to a lesser extent shape, and although it is illuminated at its head by the T Tauri variable star R Monocerotis, its variability doesn’t exactly match that of the star. This unusual behaviour is caused by dust clouds orbiting close to the star, blocking its light and casting shadows across the nebula. Located 4.4° south-southwest of mag. +3.3 Alzirr (Xi (j) Geminorum), it is visible in a 4-inch telescope, though the nebula’s curved wedge shape is more clearly revealed through an 8-inch telescope at around 120x magnification.  SEEN IT S ABOUT THE WRITER Steve Richards is a seasoned deep-sky observer and our equipment expert. Read his Deep-sky tour each month on page 56.

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42

ESA/NASA X 3, THINKSTOCK X 5

The Expedition 34 crew gather in a very festive Unity module

ISS F

or most people, Christmas is a time to gather with family and friends. But not everyone gets to spend the holiday at home – the six astronauts on the International Space Station (ISS) don’t even get to be on their home planet. This isn’t lost on the various space agencies involved in the ISS: they try to make Christmas Day as festive and memorable as possible for the astronauts on board. Just as they would at home,

skyatnightmagazine.com 2013

the astronauts put up decorations – specially made so they are safe for use on the ISS. A small plastic tree, sometimes attached to the ceiling or otherwise left to float around, has been part of the space station’s essential supplies for many years, as have the garlands, Santa hats and the Christmas stockings personalised for each crew. In 2010, ESA astronaut Paolo Nespoli of Expedition 26 awoke with the rest of his crew on Christmas morning to find gifts tied to

Þ The pre-Christmas resupply is an exciting affair, with extra goodies lurking among the essentials

one of the hatches. “This discovery was really astonishing because none of us put them there. It was a real surprise.” To this day, no one has admitted doing it. “Of course, it must have been Father Christmas who put them there!” he jokes.

Chimney conundrum Regardless of whether Santa hurries down the chimney or not – or in the case of the ISS, through a vent – presents remain an important part of the celebrations. Even in space, astronauts can still get gifts from their loved ones. “We have a small container that families can put stuff in that we don’t know about, to surprise

“The crew of Expedition 26 awoke on Christmas morning to find gifts tied to one of the hatches” us,” says NASA astronaut Tom Marshburn, who spent last Christmas on the ISS as part of Expedition 34. “But they have to do that about a year in advance.” His Expedition 34 comrade Chris Hadfield had also thought about how he could make the day special for his crewmates ahead of time. Before he left Earth, Hadfield paid a visit to all the spouses of his fellow astronauts to collect handwritten cards for Christmas Day. As you might expect, the crew spends the day itself eating too much at a big communal meal. Last year the crew dined in the space station’s Russian segment, where the cosmonauts gave a sliced apple and a tin of caviar to each of their companions. Their Christmas feast was a turkey dinner with yams. Hadfield later cracked out the guitar and began to sing carols to entertain mission control back on >

44 CHRISTMAS ON THE ISS DECEMBER

Þ Commander Scott Kelly of Expedition 26 shows off some of the decorations specially made for the ISS

“Being away from the world has its downside but every astronaut agrees it’s worth it” >

Þ Hadfield’s YouTube success led to bigger things – his take on Bowie’s Space Oddity has had 18 million views However, the distance can bring a new perspective to the day. Hadfield took the opportunity to record the first carol in space, a song written by his brother called Jewel in the Night. The song, an ode to Earth as seen through the cupola, has picked up more than 240,000 hits on YouTube – no mean feat for something recorded in one take using an iPad. “To be able to record something as peaceful and ancient as a Christmas carol from a new place gave a new perspective, not only for me personally, but also for us as a species,” says Hadfield. “It was lovely being able to bring that to the world through social media in time for Christmas last year.” Being away from the world has its downside but every astronaut agrees that it’s worth it. “We were a long way from home,” says Hadfield, “but still in the company of people we like and respect. There was a great feeling of connectedness despite the distance.” With the long nights upon us, you may be able to spot the ISS passing over the UK in the run up to Christmas – your very own jewel in the night. And if you do so, spare a thought for those six people passing over your heads, looking down on the world below. S ABOUT THE WRITER Elizabeth Pearson is BBC Sky at Night Magazine’s staff writer. She has recently finished writing her thesis on extragalactic astronomy at Cardiff University.

ESA/NASA X 3, THINKSTOCK X 3, CHRIS HADFIELD/YOUTUBE

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THE SKY GUIDE DECEMBER 47

Twilight treats The evening and morning twilight is full of astronomical delights this month. Comet C/2012 S1 ISON should be visible if it survives perihelion, and there are some delightful thin lunar crescents and bright planets on offer too.

The Sky Guide

December OUR STARGAZING EXPERTS PETE LAWRENCE As well as writing The Sky Guide, Pete can be seen on BBC’s The Sky at Night. On page 60, he offers advice on how to image comet C/2012 S1 ISON against darker skies.

PETE LAWRENCE

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. 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. skyatnightmagazine.com 2013

48

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

1

SUNDAY If it survives perihelion on 28 November, comet C/2012 S1 ISON should be visible in both the dawn and evening twilights. Although the comet is now fading, it should still be visible to the naked eye and may have a decent tail. See page 50. Mag. +0.9 Saturn, mag. –0.6 Mercury and a thin waning crescent Moon (3% lit) are low in the southeastern sky just before sunrise and form an isosceles triangle, with the Moon 2º from Saturn. See page 51.

9

W MONDAY Jupiter lies just 15 arcminutes away from mag. +3.5 Wasat (Delta (b) Geminorum) today and tomorrow. Closest approach occurs on 10 December, but the difference is just a few arcseconds.

19

THURSDAY The waning gibbous Moon (97% lit) is 5.5º below mag. –2.5 Jupiter in the early hours of the morning.

26 PETE LAWRENCE X 6

THURSDAY Mag. +0.9 Mars is a little less than 6º above the waning crescent Moon (43% lit) this morning.

Comet C/2012 S1 ISON is at its closest to Earth today. Fear not – the comet is still 64.2 million km away and poses no threat to our planet.

skyatnightmagazine.com 2013

21

2

MONDAY Saturn and Mercury point towards a very thin waning crescent Moon (0.8% lit) rising just before the Sun. Spotting the Moon at this time requires a very flat horizon and clear skies. See page 51. From tonight until the 10th is a good time to take our Deep-sky tour, as is the 24th to the 31st. See page 56.

5

THURSDAY The waxing crescent Moon (10% lit) and mag. –4.6 Venus are low in the southwest from around 17:00 UT. At this time they will be separated by 7.5º and should look quite stunning as the sky darkens.

11

WEDNESDAY X The waxing gibbous Moon (64% lit) occults mag. +4.3 Epsilon (¡) Piscium this evening. The star disappears behind the Moon’s dark edge at about 22:10 UT and reappears from behind its bright edge at around 23:17 UT – times will vary with location. See page 51.

SATURDAY At 17:11 UT the centre of the Sun will reach its lowest point in the sky. Before this time the Sun will be moving southward against the stars; afterwards it is moving northward. The exact point of direction change represents a time when the Sun is effectively stationary for a brief instant – a point known as the winter solstice.

3

TUESDAY If you have a very flat southwestern horizon, try to locate the very thin waxing crescent Moon (0.7% lit) just after sunset. Like the matching waning crescent visible on the morning of 2 December, this is a tricky but rewarding target.

6

FRIDAY There’s another chance to catch the waxing crescent Moon (now 18% lit) and Venus low in the southwest as the sky darkens.

Comet C/2012 S1 ISON is 0.5º from mag. +2.7 Delta (b) Ophiuchi, visible in the morning sky.

THE SKY GUIDE DECEMBER 49

What the team will be observing in December Pete Lawrence “I’ll be trying to get as many views of comet C/2012 S1 ISON as I can. With the Moon out of the way and the head of the comet at its brightest in the early part of the month, the chase will be to find it in twilight!”

4

WEDNESDAY The magnificent constellation of Orion is at its highest point in the sky, due south around midnight. With the Moon out of the way, this is a great time to explore the Hunter and the surrounding area.

Stephen Tonkin “Although Geminid meteors are sometimes bright enough to be seen in the skyglow of the gibbous Moon, I’ll be watching them in ideal conditions between moonset (05:00 UT) and dawn twilight on the 14th.” Chris Bramley “It’s a great time to investigate the many and varied treasures in Orion. I’ll start off by contrasting the colours of red supergiant Betelgeuse and blue-white Rigel.”

Terms you need to know

13

FRIDAY The Geminid meteor shower, arguably the best of the year with a zenithal hourly rate of up to 120 meteors per hour, hits peak activity on the night of 13/14 December. Sadly the waxing gibbous Moon (90% lit) is up for most of the night and will drown out all but the brightest trails.

15

SUNDAY The almost-full Moon (97% lit) passes through the northern section of the Hyades open cluster in Taurus this evening. The bright star you can see just below the Moon is mag. +0.8 Aldebaran (Alpha (_) Tauri); it marks the eye of the Bull.

UNIVERSAL TIME (UT) Events are given in Universal Time (UT), the standard time used by astronomers worldwide. UT is the same as GMT. RA (RIGHT ASCENSION) AND DEC. (DECLINATION) These coordinates are the night sky’s equivalent of longitude and latitude, describing where an object lies on the celestial ‘globe’.

Icons explained How to tell what equipment you’ll need NAKED EYE

22

Allow 20 minutes to become dark-adapted

SUNDAY X Comet C/2012 S1 ISON lies 5º from M13, the Great Globular Cluster in Hercules. See page 50.

BINOCULARS 10x50 recommended

PHOTO OPPORTUNITY Use a CCD, webcam or standard DSLR SMALL SCOPE Reflector/SCT under 150mm, refractor under 100mm

27

FRIDAY The mag. +1.0 star lying just 0.5º from the waning crescent Moon (34% lit) is Spica (Alpha (_) Virginis). The pair pop above the east-southeast horizon at around 02:00 UT. This is when they will appear to be at their closest from the UK.

29

SUNDAY The waning crescent Moon (14% lit) is just 4º from mag. +0.9 Saturn when it rises at around 06:00 UT. Look low in the southeast.

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.

skyatnightmagazine.com 2013

50

DON’T MISS... 3 TOP SIGHTS Comet C/2012 S1 ISON after perihelion WHEN: All month, but the Moon interferes from 16-26 December It’s hoped the comet will possess a long tail after its close pass of the Sun

the inner Solar System may be the first week of December. Following perihelion, the comet is next visible in the dawn sky on 29 November, its head very close to the Sun. All hopes are that it will have developed an impressive tail at this time. A lengthy bright tail may also be visible before the head rises, when the skies are darker. The comet’s head is expected to be around mag. –2.0 on the 29th, fading quite rapidly over

COMETS HAVE NO respect for magazine deadlines, so bear in mind that what’s written here is being committed to paper before comet C/2012 S1 ISON had its close encounter with the Sun on 28 November. What happens after this date depends whether the comet survives perihelion and the sort of activity it shows as a result of this close call. Assuming it does survive, the best opportunity to spot this one-time visitor to

the following few days. Even by the evening of the 29th it will be about mag. –0.9 and still very close to the Sun. As we move into December it will become dimmer but be better positioned against ever darkening skies. By the morning of 1 December, C/2012 S1 ISON is estimated to be mag. +1.4 with its tail pointing up away from the Sun. The head of the comet rises about 70 minutes before our star. In the evening, the

URSA MAJOR

URSA MINOR

LEO

CANES VENATICI Denebola

31 Dec

DRACO

COMA BERENICES

Comet C/2012 S1 ISON 26 Dec

BOÖTES

CYGNUS 21 Dec M13

Vega

VIRGO

Arcturus

CORONA BOREALIS

Spica 16 Dec

LYRA

HERCULES

SERPENS

comet sets about 40 minutes after sunset, this time with the tail making a shallower angle with the western horizon. Its brightness is estimated to be around mag. +1.7 at this time. This morning-evening double act continues, with the comet gradually gaining greater separation from the Sun with each passing day – but fading too. By 10 December, the comet rises some 3.5 hours before the Sun but is predicted to be mag. +4.4. The evening appearance sees it above the horizon for one hour and 40 minutes after sunset. The Moon interferes from the 16th and despite it being close to the opposite horizon at dawn on this date, its light will cause issues with the appearance of the comet’s tail. By 22 December, as the Moon wanes, the comet will be about 5º from globular cluster M13 in Hercules – this should be a good photo opportunity. The comet crosses the circumpolar threshold after this. C/2012 S1 ISON is closest to Earth on 26 December, just as it’s approaching the threshold of naked-eye visibility. At this time it’s located between Hercules and Draco, heading towards an encounter with Polaris early next month.

PETE LAWRENCE X 4

! E

SE

C/2012 S1 ISON is inching farther and farther from the Sun – meaning you can see it against increasingly dark skies

skyatnightmagazine.com 2013

NEED TO KNOW

C/2012 S1 ISON is thought to hail from the Oort Cloud, a theorised but unseen reservoir that could hold trillions of comets.

THE SKY GUIDE DECEMBER 51

Twilight observing WHEN: Dawn and evening twilight as specified

THERE’S A LOT going on in both the evening and morning twilights this month. There’s the potential for an impressive comet show, details of which can be found opposite. On the morning of 1 December, mag. –0.6 Mercury, mag. +0.9 Saturn and a delicate waning crescent Moon (3% lit) can be seen low in the southeast just before sunrise, which from the centre of the UK occurs at around 08:00 UT. See if you can spot Zubenelgenubi (Alpha (_) Librae) at this time, just to the upper right of the Moon. This is a double star with components of mag. +2.8 and +5.1, separated by 3 arcminutes and 51 arcseconds. Over the next few days, Mercury creeps closer to the Sun, while Saturn appears to creep very slowly away from it. Mercury will probably be lost

to the glare by the end of the first week of December. On the 2nd, before this occurs, an extremely thin waning crescent Moon (0.8% lit) sits between Mercury and the Sun just before sunrise. Please be careful if looking for it and never look when the Sun’s above the horizon. The Moon lies on the same line drawn between Saturn and Mercury. You’ll get another go at trying to locate the thin crescent on the evening of the 3rd, when a similarly slim one hugs the southwest horizon just after sunset, which from the centre of the UK occurs at 16:00 UT. This will also be a tricky spot and again, please only try if the Sun has well and truly set first. If you find locating these two ultra-thin crescents too hard, then there’s a slightly

See if you can spot two ultra-thin crescents on the 2nd and the 3rd

easier pre-sunrise crescent Moon (2% lit) visible on morning of the 31st, low in

the southeast; a lovely end to what has been an exciting year for astronomy.

Occultation of Epsilon Piscium WHEN: 11 December, from 21:55 UT

THE MOON WILL pass in front of mag. +4.2 Epsilon (¡) Piscium on the evening of 11 December, giving you the opportunity to see the star both vanish behind and reappear from the Moon. Epsilon Piscium will be hidden by the dark edge of the waxing Moon at around 22:10 UT if you are in the centre of the UK – times will vary depending on your location. To observe the event, locate the star either with binoculars or a telescope from 21:55 UT and stare at it. Disappearance is an instantaneous event as the point source of light that is Epsilon Piscium passes behind the sharp airless limb of the Moon. It’s amazing how the

Apparent motion of the Moon

Disappearance (22:10 UT from the centre of the UK)

Reappearance (23:17 UT from the centre of the UK)

It’s a good idea to get set up in good time – 15 minutes beforehand should be plenty

excitement builds as this time approaches – if you blink at the wrong moment, you’ll miss it completely. Reappearance occurs about 67 minutes later, again depending on location. The star will emerge from just below the mid-point of the Moon’s bright edge.

To make sure you don’t miss the two pivotal moments, we’d recommend observing roughly 15 minutes before disappearance (from 21:55 UT) and reappearance (from 23:00 UT). If you’re thinking of imaging the event, try and capture the star next to the

Moon’s edge. Don’t forget to send your image to hotshots @skyatnightmagazine.com.

!

NEED TO KNOW

The brightness of a star is known as its magnitude – the lower the number, the brighter the star. You can see down to mag. +6.0 with the naked eye.

skyatnightmagazine.com 2013

52

THE PLANETS Pick of the month Castor

_

JUPITER

M35

GEMINI

BEST TIME IN DECEMBER:

31 December, 00:30 UT ALTITUDE: 59º LOCATION: Gemini DIRECTION: South RECOMMENDED EQUIPMENT:

Pollux

` Jupiter

3-inch telescope or larger

Moon

31 Dec

1 Dec

17 Dec

b Wasat

FEATURES OF INTEREST:

North and South Equatorial Belts, Great Red Spot, Galilean moons

Alhena

Moon

18 Dec

a

ORION

JUPITER IS A magnificent sight at the moment. The planet reaches opposition next month on 5 January, at which time it Moon 17 Dec will appear at its best. For a month either side of this date, Jupiter remains very impressive indeed. To the naked eye Jupiter hangs around in Gemini throughout the month, clearly brighter than the stars around it it dominates the constellation of lie either side of Jupiter’s equator. Known Gemini, currently being quite more oval than circular. This as the Southern and Northern Equatorial close to the mag. +3.5 Wasat is a consequence of its rapid Belts (SEB and NEB), these are the most (Delta (b) Geminorum). rotation combined with it prominent of the features on view. The At mag. –2.4, it’s much being a gas giant planet. SEB also plays host to a famous long-term brighter than any of the Different parts of the storm on the planet known as the Great night time stars. planet rotate at slightly Red Spot, which is visible between 22:00 A telescope really different rates, but all UT and midnight on the 2nd, 7th, 12th, brings the planet to life, complete one revolution 14th, 19th, 24th, 26th and 31st. something helped by the in less than 10 hours. If Jupiter has a huge family of over 60 fact that Jupiter has a large, Jupiter looks like a bright moons, but only the brightest four – the 45-arcsecond disc that is full of washed-out disc, give your Galilean moons – can be easily seen with detail. The first thing you’ll The planet presents eyes time to adjust. amateur scopes. They can even be spotted notice is that the planet appears a 45-arcsecond disc The first thing you’ll notice with plenty of detail will be the two darker belts that with binoculars if you have a steady hand. slightly squashed and rather

How the planets will appear this month The phase, tilt and relative sizes of the planets in December. Each planet is shown with south at the top, to show what it looks like through a telescope VENUS 15 Dec

MARS 15 Dec

JUPITER 15 Dec

SATURN 15 Dec

URANUS 15 Dec

NEPTUNE 15 Dec

20” 30” 40” ARCSECONDS

50”

MERCURY 1 Dec

PETE LAWRENCE X 2

MERCURY 15 Dec MERCURY 31 Dec 0”

skyatnightmagazine.com 2013

10”

1’

THE SKY GUIDE DECEMBER 53

MERCURY BEST TIME IN DECEMBER:

1 December, 07:00 UT ALTITUDE: 5º (low) LOCATION: Libra DIRECTION: Southeast Mercury isn’t well placed for most of the month. The planet is passing along part of its orbit farthest from Earth and currently appears to be moving towards the Sun. Its apparent motion in the dawn twilight is slow and it takes most of the month to reach superior conjunction on the 29th. The start of the month is the best time to try and see it – the planet should just be visible low in the southeast just before sunrise.

mag. +1.2, the planet looks like a pink star to the naked eye. It passes 1º north of mag. +3.6 Zavijava (Beta (`) Virginis) on the 3rd and is just over 0.5º from mag. +2.7 Porrima (Gamma (a) Virginis) on the 29th. Mars will be mag. +0.9 at this time. SATURN BEST TIME IN DECEMBER:

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

31 December, 06:15 UT ALTITUDE: 14º LOCATION: Libra DIRECTION: Southeast

Saturn is slowly crawling out from the dawn twilight and re-emerging into the morning sky. The planet currently appears as a mag. +0.9 star with a slight yellowish hue to the naked eye.

VENUS

1 2 3 4 5 6

BEST TIME IN DECEMBER:

URANUS

5 December, from 17:00 UT ALTITUDE: 7º (low) LOCATION: Sagittarius DIRECTION: Southwest Venus is an evening object shining in the post-sunset twilight at mag. –4.6. A scope will reveal a wonderful 30% lit Venusian crescent on the 1st, 37 arcseconds across. Inferior conjunction, the time when Venus lines up with the Sun on the earthward part of its orbit, occurs next month. Between now and that time, Venus appears to get closer to the Sun.

BEST TIME IN DECEMBER:

7

1 December, 20:00 UT

8

Ice giant Uranus has an altitude of 40 º as darkness falls at the start of the month, slightly east of south. At mag. +5.8, it is possible to see Uranus with the naked eye, but you’ll need a clear dark sky. It currently lies in a barren region, just to the south of the ‘rope’ of Pisces, about 6º to southwest of the fourth-magnitude stars Epsilon (¡) and Delta (b) Piscium.

MARS

NEPTUNE

BEST TIME IN DECEMBER:

BEST TIME IN DECEMBER:

ALTITUDE: 40º LOCATION: Pisces DIRECTION: South

JUPITER IN DECEMBER WEST EAST

DATE

9 10 11 12 13 14 15 16 17 18 19

31 December, from 05:30 UT

1 December, 17:40 UT

ALTITUDE: 34º LOCATION: Virgo DIRECTION: South

ALTITUDE: 26º LOCATION: Aquarius DIRECTION: South

Mars is now gaining a serious foothold in the morning sky as it passes through Virgo. It’s not at its highest in the sky during darkness at the start of the month, but does manage to climb to this optimal position by the end of December. Telescopically Mars is quite small, being just 6 arcseconds across on New Year’s Eve. At

Neptune is at its highest point in the sky, about 25º up, due south, as darkness falls at the start of December. The planet is in Aquarius, 3.5º south of mag. +4.2 Theta (e) Aquarii. Neptune is mag. +7.0, so you’ll need binoculars to spot it. By the end of the month, Neptune loses altitude by the time darkness falls.

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

20 21 22 23 24 25 26 27 28 29 30 31 8 7 6 5 4 3 2 1 0 1 2 3 4

5 6 7 8

arcminutes

Jupiter

Io

Europa

Ganymede

Callisto

skyatnightmagazine.com 2013

54

NORTHERN HEMISPHERE

RT O N

HE A ST

When to use this chart 1 DEC AT 00:00 UT > 15 DEC AT 23:00 UT > 31 DEC AT 22:00 UT

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

How to use this chart

C

EAST

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.

22

DATE

SUNRISE

01 Dec 2013

08:02 UT

15:55 UT

11 Dec 2013

08:15 UT

15:50 UT

nd

The Sun and Moon this month SUNSET

15:52 UT

08:26 UT

16:00 UT

DATE

MOONRISE

MOONSET

01 Dec 2013

05:50 UT

15:04 UT

11 Dec 2013

12:55 UT

01:38 UT

21 Dec 2013

20:28 UT

10:13 UT

31 Dec 2013

06:56 UT

15:27 UT

A DR

08:23 UT

31 Dec 2013

HY

21 Dec 2013

Times are given for the centre of the UK.

Moon phases in December SATURDAY

SUNDAY

MONDAY

TUESDAY

1

2

3

7

8

9

14

15

21

28

WEDNESDAY THURSDAY

FRIDAY

4

5

6

10

11

12

13

16

17

18

19

20

22

23

24

25

26

27

29

30

31

skyatnightmagazine.com 2013

S EA

FULL MOON

H UT SO

CHART CONVERSION BY PAUL WOOTTON

NEW MOON

T

NORTH

THE SKY GUIDE DECEMBER 55

Key to star charts ES T

O

UT HW

ES T

WEST

N

O

RT HW

S

SOUTH

skyatnightmagazine.com 2013

56

DEEP-SKY TOUR With Steve Richards

colour contrasts here, with yellow, orange and blue stars all within the field of view. Sweep 1.7° east from Arneb to find the asterism.  SEEN IT

Follow us to a rare carbon star, an out of place globular and an old flame  

Tick the box when you’ve seen each one

3

4

Spend a bit of time with the Flame Nebula and its subtle features will reveal themselves

CHART: PETE LAWRENCE, FLAME NEBULA: THINKSTOCK

1

2

M79

This month’s tour is set in the deep south and starts in the constellation of Lepus, the Hare. Our first object, globular cluster M79, is somewhat challenging – and for a globular it is rather out of place, being located so far from the galactic centre. Imagine a line between mag. +2.6 Arneb (Alpha (_) Leporis) and mag. +2.8 Nihal (Beta (`) Leporis) and extend it the same distance again to locate the cluster. A 6- to 8-inch telescope shows a faint soft glow with little detail, but ramping up the magnification to 250x in a 10-inch or larger instrument will start to reveal the typical granular nature of this type of object.  SEEN IT

NGC 2017

Our second object is much less challenging and a lovely sight in a 3- to 4-inch telescope. NGC 2017 was originally believed to be an open cluster, but more recently has been reclassified as a multiple star system, and it forms an asterism with some attractive foreground and background stars. This asterism is 4 arcminutes square and comprises three 8th-magnitude stars surrounding a 6th-magnitude central star, although other fainter stars are also visible through large-aperture instruments. There are some nice

skyatnightmagazine.com 2013

5

6

HIND’S CRIMSON STAR

Object number three is a rare and beautiful carbon star. R Leporis was discovered by English astronomer and asteroid hunter John Russell Hind in 1845, and is commonly known as Hind’s Crimson Star. It’s a Mira-type variable with a long period of around 432 days and a magnitude that varies from +5.5 to +11.7. The star’s incredibly deep red colour is caused by its relative coolness, which removes much of the blue starlight emission, leaving the red to dominate. A small telescope will easily reveal the star – from Arneb, follow a line through mag. +3.3 Mu (+) Leporis and continue for a little more than half the distance again.  SEEN IT

RIGEL

Moving up into Orion now, we are seeking the brightest star in the constellation and the seventh brightest star in the sky at mag. +0.18. Rigel (Beta (`) Orionis) lies at the bottom-right of the Hunter, marking his left foot, and its bluish-white colour contrasts beautifully against the orange-red of Betelgeuse. Rigel is a triple star system, with Rigel A and B forming a spectroscopic binary. Rigel B does take some seeing as the glare from the incredibly bright Rigel A overpowers it, but the stars can be split in a 3-inch telescope. A 4- to 6-inch scope will make the task easier.  SEEN IT

THE FLAME NEBULA

Our next object is very popular with astro imagers but it is well worth seeking out for observation too. The wonderful Flame Nebula, NGC 2024, lies a fraction to the northeast of mag. +1.7 Alnitak (Zeta (c) Orionis), the most easterly of the three stars in Orion’s Belt. The sheer brightness of Alnitak is an impediment to observing this emission nebula, but placing the star just outside the field of view of a 6-inch telescope will allow you to discern its leaf shape. It’s crucial to spend some time letting your eyes adapt to the view – more detail will appear, culminating with the strong, dark dust lane at its centre.  SEEN IT

M78

For our final object on this tour, sweep 2.5° northnortheast to find a very different type of nebula, M78. This lovely reflection nebula is the brightest part of a large expanse of gas known as the Orion Molecular Cloud, which is drifting across the whole of the constellation of Orion. Whereas observations of emission nebulae can be enhanced with the use of various filters, unfortunately, these don’t help with reflection nebulae. However, careful scrutiny through a 6-inch telescope at about 120x magnification will reveal a fan-like glow with two quite prominent stars, HD 38563A and HD 38563B. Their light reflects off the dust, making the nebula visible.  SEEN IT

0º

05h

NGC 1637 Collinder 70

6

NGC 2071 0º

NGC 2112

M78

+

b

Alnilam

d

¡

Alnitak

ORION

c

NGC 2024

m

5

06h

Mintaka

ERIDANUS Cursa

IC 434

`

NGC 1981 M43

t

NGC 1977 M42

f

NGC 1980

-10º

` p

Rigel

4

f

g Saiph

g IC 418

3

h

-10º

R + d

c

LEPUS

2

_

-20º

Arneb

NGC 2017

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58 10x50 binoculars you should see a shape vaguely similar to that of the brighter stars of the constellation Delphinus, hinting at this asterism’s common name. Look to the northeast of the Minnow to find the ‘Splash’, which includes mag. +5.0 Phi (q) Aurigae. Counting the Splash as well, you should see at least 30 stars.  SEEN IT

BINOCULAR TOUR With Stephen Tonkin There are clusters and myths aplenty as we home in on Taurus and Auriga  

5 A TRIO OF CLUSTERS 10 x If you put Phi (q) Aurigae on the right50 hand side of the field of view, you should see two fuzzy patches, one above and one below the centre. The upper, slightly larger one is M38 and the lower, brighter one is M36. Put M36 near the top of the field of view and another fuzzy patch, larger and brighter than either of the previous two should be near the bottom of the field. This is M37 which, with a distance of nearly 4,500 lightyears, is about 500 lightyears farther away than the other two.  SEEN IT

Tick the box when you’ve seen each one

1 THE PLEIADES 10 x We start with what may be the most 50 spectacular binocular object, the Pleiades, M45. Also known as the Seven Sisters, this open cluster is an easy naked-eye object, but put it in the field of small binoculars and it is like opening a jewel box; inside are hot blue stars only about 100 million years old. Even in suburban skies, you should see about 40 stars; in dark skies it is easy to lose count.  SEEN IT

2 THE HYADES 10 x The Hyades is another open cluster, sitting 50 adjacent to the reddish eye of Taurus, mag. +1.0 Aldebaran (Alpha (_) Tauri). The Hyades will spread beyond the field of view of all but wide-angle binoculars – you should easily see 30 or more stars. The Hyades is only 153 lightyears away, making it the nearest open cluster to us. In mythology, the Hyades were the daughters of Atlas. They are said to be weeping for their brother, Hyas – who was slain by a lion – and

their tears are the rain associated with the cluster’s heliacal rising in spring.  SEEN IT

3 NGC 1647 15 x About 3° northeast of Aldebaran is the 70 lovely little open cluster NGC 1647, which is often ignored because of the presence of its more illustrious neighbours, the Hyades and Pleiades. You should be able to count about 20 stars in an area about one and a half times the apparent size of the Moon. This is most impressive given its great distance of 1,790 lightyears, which suggests it is more than twice as large as the Hyades. NGC 1647 is much easier to identify in binoculars than in a telescope, where it may not appear to be an obvious cluster.  SEEN IT

We finish this month’s tour with a real 15 x 70 challenge, for which you will need a very transparent sky and mounted binoculars. Place the blue-white mag. +4.0 Menkib (Xi (j) Persei) halfway between the centre and the 5 o’clock position of the edge of the field of view. Use averted vision and look for a variation in sky brightness, with an elongated brighter patch crossing the central half of the field. This is the California Nebula, NGC 1499. If you have a very dark site, you may find it easier in 10x50 or even 8x42 binoculars.  SEEN IT

4 THE LEAPING MINNOW 10 x Just over 4° east of mag. +2.7 Hassaleh 50 (Iota (f) Aurigae), lies a little group of stars of approximately magnitude +5.0, which includes 14, 16, 17 and 19 Aurigae. In a pair of

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THE SKY GUIDE DECEMBER 59 N

MARE IMBRIUM

E ARCHIMEDES

RIMAE FRESNEL

PALUS PUTREDINUS

Palus Putredinus RIMA HADLEY

HADLEY C

MONS HADLEY

TYPE: Marsh SIZE: 160km by 70km AGE: 3.2 to 3.9 billion years old LOCATION: Latitude 27.0°N, longitude 0.0°E BEST TIME TO OBSERVE: One day after first quarter (evening of 10 December) or seven days after full Moon (morning of 24 December) MINIMUM EQUIPMENT: 10x binoculars

The Palus Putredinus is home to subtle features as well as a signpost to more familiar ones

MOONWATCH With Pete Lawrence “There are three lunar marshes visible from Earth. They mark irregular regions of enclosed lava found at the edge of the major seas” DESPITE WATER BEING a scarcity on the Moon, there are plenty of features with names that imply otherwise: the lunar maria, or seas, for example. Then there are the smaller ‘water’ features prefixed with terms such as sinus (bay), lacus (lake) and palus (marsh). There are three lunar marshes visible from Earth. They mark irregular regions of enclosed lava found at the edge of the major seas. Despite its off-putting name, the Palus Putredinus – which means Marsh of Decay – and its surrounding area is a fascinating region. It sits adjacent to the Appenine mountain range boundary on the southeast edge of the huge Imbrium Basin. The best way to locate it is to first identify

85km-wide Archimedes, the largest crater on the floor of Mare Imbrium. Draw a line from Archimedes to the nearest part of the curving Appenine range, off to the southeast. The marsh appears along this line as a dark region of lava, roughly rectangular in shape. Its width is slightly less than Archimedes’s diameter. The Palus Putredinus is a flat area of lava covered in tiny craterlets. A volcanic dome called Putredinus 1 can be found in its southern corner. This has a diameter of 7km and is estimated to be 90m high. You’ll need a 12-inch telescope to spot the dome; the best time to try is when the terminator is nearby and the lighting oblique.

The southeast ‘edge’ of the marsh is interesting, as a broken line of mountains creates an annexed region of lava. Within the narrow, 18km by 60km annex is a 6km crater called Hadley C, which can be seen with a 4-inch telescope. An 8-inch scope will reveal a wonderful sinuous rille known as Rima Hadley winding its way across the annexed lava floor past the crater. Towering above the rille to the east is Mons Hadley, a 4.6km-high member of the Appenine range. There are various straight rilles heading out of the southwestern edge of Palus Putredinus, leading to an area unofficially referred to as the Appenine Bench Formation. This region is unusual in that it’s rich in KREEP: this is an acronym for potassium (chemical symbol K), rare Earth elements (REE) and phosphorous (P). A rarity on the Moon, KREEP is believed to have been brought up from deep below Mare Imbrium, possibly by volcanic processes. A similar KREEP-rich region sits above the eastern corner of Palus Putredinus. This is fascinating to study with a 8-inch or larger scope because of Rimae Fresnel, a set of graben that cross it. A graben is a linear region of land which has dropped between fault cracks in the surface. skyatnightmagazine.com 2013

60

ASTRO PHOTOGRAPHY With Pete Lawrence

A dark-sky comet Recommended equipment DSLR camera, 50mm lens, equatorial tracking mount, shutter release cable

IF YOU HAVE been trying to get shots of comet C/2012 S1 ISON already, you may have realised that comets aren’t always the easiest objects in the night sky to take pictures of. Throughout November, the comet headed towards the Sun and was visible in the morning twilight. Some of the techniques required to deal with everchanging light levels were covered in this section last month and these will also be useful for the early part of December, when the comet will be at its brightest during the month but still located against a bright twilight sky. In fact, there will be two opportunities to see it during the day: one in the dawn twilight and one in the evening twilight. As the month progresses, the comet will move farther from the Sun in the sky, offering an opportunity to image it

against a darker background. If you have an equatorially mounted telescope driven in right ascension, you might think that long-exposure images will work best, but C/2012 S1 ISON is not going to play that easy to catch. The problem is that the comet has its own relative motion against the fixed background stars and this can be high enough to show motion blur on relatively short exposures. The length of exposure you can get away with without blurring becoming an issue depends on several factors, including focal length, the apparent speed of the comet against the background stars and your personal preference. Focal length should really be determined by the apparent size of the comet in the sky and what lenses you have to hand. At the time of writing, the apparent size of the tail around perihelion is an unknown

quantity but, under ideal activity it could extend for several degrees or even tens of degrees across the sky. If the comet has a long tail, you may need to use a shorter focal length than anticipated to get it all in – this will result in a lower image scale and less blur for a given exposure time. Shorter focal lengths will also be more forgiving of polar alignment inaccuracies. The relative motion and the amount of blurring are exacerbated by magnification. Use a long focal length lens or telescope and the effect is more noticeable. The Plough is a reliable measure to help you gauge the comet’s size. The asterism’s full length is 25º, while the handle is 15º long. The wide part of the pan is 10º across and the middle height of the pan is 5º.

Exposure escapades On a non-full-frame DSLR, a 50mm lens covers an area of sky measuring 25º by 17º. A 100mm lens halves these dimensions to 12.5º by 8.5º, while a 200mm lens gives 6.25º by 4.25º. How you fit the comet in the frame is up to you, but aesthetically it’s nice to have a bit of normal sky around it for context. Determine the length of exposure you can get away by taking a shot and examining the results. If you’re not sure how much the comet has moved during the exposure, take several shots and advance through them. The comet’s motion should be obvious. I’d normally try for a minute’s exposure to start with, using a mid-range ISO, say of 400-800. Check the comet’s appearance and if it’s not too blurred increase to 90 seconds or

ALL PICTURES: PETE LAWRENCE

How to get a detailed glimpse of the comet

STEP 1 Select the lens or telescope you want to use by determining how big the comet appears in the sky. This may require you to take a wide-field shot with a short focal length lens first. Comet tails can be very diffuse and extend farther than you can see with your eye alone. A typical 50mm lens covers 25º by 17º on a non-full-frame DSLR.

skyatnightmagazine.com 2013

STEP 2 An equatorial mount driven in right ascension will remove star trailing for short exposures of 60-120 seconds. If using a telescope, the more accurate your polar alignment, the longer your exposures can be before trailing becomes an issue. For wide-angle camera lenses, longer exposures should be possible without trailing being evident.

STEP 3 Initially set your camera to a mid-range ISO, say 400-800, select RAW as the image file format and, if using a camera lens, fully open it using the lowest f-stop available. Accurate focus is vitally important. If the Moon’s up, focus on that. Cameras with live view can be carefully focused on a bright star. Take a test shot to check that you have focused correctly.

THE SKY GUIDE DECEMBER 61

even 120 seconds. Be aware that the longer the exposure, the greater the likelihood of star trailing due to mount alignment errors. The star-like region at the centre of the comet’s head will typically overexpose, but it’s a good idea to try and keep the size of the white region to a minimum – in other words, keep it looking like a star. You can make use of longer exposures by stacking the results – we’d suggest using freeware program DeepSkyStacker. Stacking combines the information in an image according to a selected method. For example, ‘averaging’ effectively adds all the signal data together then divides it by the number of images used. This results in an image which has a better signal-to-noise ratio, as noise varies between images while the target’s signal doesn’t. The noise is effectively smoothed out as a result. Before this can happen, the images must be accurately aligned to one another. There are three options for doing this, detailed in Step 6 below. Aligning all the images so the stars line up will give a combined result which simply reinstates the unwanted motion blur in the comet. Alternatively, aligning images on the comet’s head produces a combined result which has a crisp image of the comet but trailed stars. The third technique gives the best of both worlds, resulting in a sharp comet and point-like stars – pick whichever one you prefer. For the best quality stacks, make sure you work with RAW files, or uncompressed TIFFs if you find these easier to view and handle.

STEP 4 Comet in frame, take test shots lasting 30, 60, 90 and 120 seconds. Identify the longest exposure that gives round stars, then use this setting to take at least 20 comet images. When done, cover the telescope and take at least nine matching dark frames using the same exposure. If you have the capability to take flat fields, these should be taken at this point too.

Advanced techniques can allow you to produce a sharp image of the comet without trailed stars

Key technique DEALING WITH MOTION BLUR You’d think that imaging a comet against a dark sky would be easier than doing so against a twilight sky, and in some respects it is. However, using longer exposures leads to another problem: assuming you’re set up to track the apparent motion of the stars, a long exposure shot will smear out the comet’s details due to motion blur. You can overcome this problem by tracking or autoguiding on the comet’s head, but there’s a simpler method – combine shorter exposures to give a deeper exposure of the comet without the annoying motion blur.

Send your image to: [email protected]

STEP 5 Run DeepSkyStacker and click on ‘Open picture files…’ and load your comet images. Load your calibration files by clicking on the relevant links. Check the light frames in the image list. Click on ‘Register checked pictures’ then ‘Ok’. Click the first light frame in the list, then on the comet icon. If the comet head isn’t identified, hold shift and click over the comet head. Repeat for all light frames.

STEP 6 Click on ‘Stack checked pictures…’, then the ‘Stacking mode’ option and select the ‘Comet’ tab in the window that opens. Choose whether you want to have sharp stars and a blurred comet, a sharp comet and blurred stars or a sharp comet and sharp stars. Finally, click ‘Save picture to file’ to save the result. Apply final tweaks using a graphics editor as you see fit.

skyatnightmagazine.com 2013

DETLEV VAN RAVENSWAAY/SCIENCE PHOTO LIBRARY

THE PLANETS

THAT SHOULDN’T

The environments populated enigmatic planets are wildly unfamiliar, finds Will Gater

EXIST

T

hink of ‘the Solar System’ and you’ll no doubt envisage a band of planets whirling around a glowing Sun. You may picture Saturn with its rings, the vast canyons and plains of an ochre Mars, or even Jupiter with its swirling cloud tops. We know these distant worlds; they’ve been Earth’s companions for a long time, and as we’ve got to know them we’ve come to accept their alien nature and the extraterrestrial landscapes they’re home to. With the advent of the space age our family of planets has become just that, familiar. To many, the diverse planets of the Solar System are as exotic as alien worlds can possibly get. Yet as astronomers have searched the Galaxy for planets around other stars, they’ve discovered worlds that defy our imaginations; and what makes many of these planets stand out are the bizarre and often hostile habitats they exist in. Here, we look at some of these extreme environments, which remind us just how pleasant our own place in space on planet Earth really is. > ABOUT THE WRITER Will Gater is an astronomy writer with a degree in astrophysics from University College London. Follow him on Twitter: @willgater.

64

EXTREME

WORLDS FROM THE CLOSEST TO THE COLDEST, THESE EXOPLANETS HOLD THE RECORDS SMALLEST Discovered in 2013 by NASA’s Kepler space telescope the roughly 3,800kmwide extrasolar planet Kepler-37b is, so far, the

FARTHEST Two worlds – SWEEPS-04 and SWEEPS-11 – share the title of the most distant exoplanets. Both were found lying over 27,000 lightyears away by the SWEEPS exoplanet survey.

CAUGHT BY

MULTIPLE STAR SYSTEMS Our Sun travels through the Milky Way alone; a solitary star among a swirl of 400 billion others. But many other stars have companions on their long journey – indeed many of these multiple star systems are visible in the night sky with small amateur scopes. Now astronomers are discovering that the neighbourhoods of these stellar partners are, in fact, places where exoplanets can survive, impervious to the gravitational waltz of their parent stars. In 2011 scientists working with NASA’s Kepler space telescope announced that they had discovered the first planet orbiting a binary star system. The planet was catalogued as Kepler-16b and lies around 200 lightyears away from our Solar System. The stars in the system orbit their common centre of mass, while Kepler-16b journeys around the pair of them in 229 days. The planet is just over 105,000km across, slightly smaller than Saturn, and analysis of its mass and size

suggests it is composed of a large rock and ice interior surrounded by gas. Intriguingly, Kepler-16b could provide clues as to how planets form around some multiple stars. One possibility is that they are swiped from a nearby planetary system during a gravitational interaction. However the orbital planes of both of Kepler-16b and its parent stars are very similar, leading the researchers to argue that the planet was born in a disc of gas and dust surrounding the two stars. Kepler-16b isn’t the only world to exist around multiple suns though. In 2012 Kepler once again hit the news when it was announced that it had found two planets – Kepler-47b and Kepler-47c – orbiting a binary star system. And just this year an international team of scientists, using telescopes in Chile and Hawaii, revealed that they had uncovered signs of as many as seven alien worlds orbiting a star in the triple star system Gliese 667.

NASA/JPL-CALTECH/T.PYLE, NASA/JPL-CALTECH/R. HURT (SSC), ESA/NASA/M. KORNMESSER (ESA/HUBBLE) AND STSCI, NASA/ESA/STSCI, AND G. BACON (STSCI), THINKSTOCK, NASA/AMES/JPL-CALTECH, ESO/L. CALÇADA

MOST POPULOUS Technically, our planetary system is the one with the most confirmed planets at eight. The star HD 10180 has seven known planets and possibly more.

SWEPT BY A

PULSAR’S BEAMS The death of a massive star is a violent affair. As it collapses, a shockwave rebounds out from the core, ripping the star apart. At the heart of this energetic event, known as a supernova, a neutron star can be formed. If this spinning, superdense ball of neutrons DARKEST TrES-2b would make a great home for the band Spinal Tap. It’s the blackest alien world we know of. Of all the light that shines on it, less than one per cent is reflected back.

is highly magnetised it can produce twin jets of radiation that revolve, like lighthouse beams. Radio astronomers can detect these objects as pulsating radio sources in the sky if the beams of radiation sweep across our line of sight. These ‘pulsars’ are probably the last place you might think to look for exoplanets, yet remarkably, the very first exoplanets were discovered orbiting in just such an extreme environment. The astronomer who made the find, Alex Wolszczan, noticed that the timing of the flashes from the pulsar, PSR B1257+12, was rather unusual. By modelling the pulsar’s behaviour he realised a system of planets must be the culprit.

SCORCHED BY

THEIR SUNS

Look at the layout of our Solar System and it’s clear that there are two main groupings of planets. Close to the Sun sit the inner rocky worlds Mercury, Venus, Earth and Mars while farther out lie the gas giants Jupiter, Saturn, Uranus and Neptune. A few other small bodies, and numerous asteroids and comets, can be found scattered around the Solar System, but those two groups dominate. It’s thought that this arrangement came about as the Solar System was forming. The volatile material in the Sun’s protoplanetary disc was driven outwards, where it coalesced into giant gaseous worlds, and what remained close to the Sun formed the inner, rocky planets. What we don’t see in our Solar System is a gas giant like Jupiter close or even closer to the Sun as, say, Mercury. Yet, incredibly, that is exactly what astronomers have found in droves in other star systems in the Milky Way – so much so that this type of exoplanet even has its own name, ‘hot Jupiters’. These huge, gaseous worlds exist in orbits that hug their parent stars tightly; in fact, if many of them were placed in our Solar System they would be

located well within the orbit of Mercury. Their nickname also reveals another shared trait of these strange alien worlds: they are incredibly hot, with atmospheric temperatures typically in the region of 1,000-1,500°C. For this reason the hot Jupiters are thought to be completely inhospitable to life as we know it. Recent studies have shown that the conditions on some hot Jupiters are truly hellish. In 2010 astronomers announced that winds of up to 10,000km/h whip around the exoplanet HD 209458b, while in 2013 Hubble astronomers revealed that the temperatures on HD 189733b are so extreme that glass could form and swirl through its atmosphere, carried by high-speed winds. But perhaps the biggest mysteries of these extrasolar worlds are how they form and how they come to be so close to their parent stars. It’s currently thought that they must migrate inwards, towards their star, after coalescing from gas and dust farther out in a protoplanetary disc.

CIRCLING DOOMED STARS Watch any sci-fi film that features an alien world and the chances are the exoplanets depicted will orbit a shining sun (or two). In other words, their parent stars are ‘alive’, just like our Sun, fusing hydrogen and other elements at their cores and releasing vast amounts of energy in the process. Yet when a star like our Sun exhausts its nuclear fuel it dies,

gracefully ejecting its atmosphere far out into space while leaving behind a tiny stellar vestige known as a ‘white dwarf’. Recently astronomers used the Hubble Space Telescope to observe two distant white dwarfs in the Hyades, a naked-eye star cluster visible at this time of year in the constellation of Taurus. By examining the light from the white dwarfs with Hubble’s advanced instruments the astronomers found the signature of silicon in their atmospheres. The team believes that this silicon comes from rocky planetary debris, such as asteroids, raining down onto the stars. And since asteroids are considered by many scientists to be the crucial ‘building blocks’ of planets like our own, it’s possible that there were – and maybe even still are – rocky worlds orbiting the stars before they died and became lifeless stellar corpses.

BLASTED BY

STELLAR FLARES If there’s one thing that the current generation of orbiting solar observatories has taught us it’s that our Sun is an incredibly dynamic star. Thanks to spacecraft like NASA’s Solar Dynamics Observatory we’ve been able to watch the Sun constantly seething and erupting, and occasionally releasing powerful blasts of radiation known as solar flares. Yet our Sun isn’t the only star that behaves this violently. Other stars release ‘stellar flares’ too. And when they do the results can be spectacular. A few years ago, a team of astronomers used the venerable Hubble Space Telescope to monitor the extrasolar planet HD 189733b,

roughly 60 lightyears away. It is a member of the class of alien worlds known as ‘hot Jupiters’ (see page 65) and, with a year just 53 hours long, it sits scorched at over 1,000°C around 5 million km from its parent star. The way its orbit is angled relative to our line of sight means that, occasionally, it passes in front of its star in what is known as a transit. The Hubble team used two such transits to study the atmosphere of HD 189733b in April 2010 and again in September 2011. The results from the 2010 transit showed that little was going on. It would be the 2011 transit that would provide the surprise.

When the astronomers looked at the September 2011 data, their jaws dropped: it told them that around a million kilograms of HD 189733b’s atmosphere was being blasted away every second. Hubble scientists believe HD 189733b’s parent star was to blame for this remarkable transformation. Just eight hours prior to Hubble’s 2011 observations, the Swift orbiting observatory had caught the star unleashing a tremendously bright X-ray flare. So the next time you’re out sunbathing, just be thankful we haven’t yet met the same fate as poor old HD 189733b.

CONSUMED BY A

NASA/ESA/L. CALÇADA, SCIENCE PHOTO LIBRARY, ESO/L. CALCADA, THINKSTOCK, NASA, ESA/NASA AND L. CALCADA (ESO FOR STSCI)

BLACK HOLE Few astronomical objects have such fearsome reputations as black holes. These celestial dark horses lurk throughout our Galaxy; indeed a supermassive black hole – with a mass some four million times greater than our Sun – hides at the very heart of the Milky Way. Astronomers study these enigmatic objects mainly by watching how they interact with their surroundings, observing the motions of stars around the Galaxy’s central black hole and even catching them in the process of eating. In January 2011 ESA’s INTEGRAL observatory detected something unusual occurring in the galaxy NGC 4845, approximately 47 million lightyears from us. INTEGRAL observes the gamma-ray and X-ray radiation from the Universe, and as it looked out into space it saw NGC 4845 suddenly brighten at X-ray wavelengths. Soon other orbiting observatories began to study the galaxy’s energetic activity too. Analysis of the observations allowed astronomers to rule out a supernova as the culprit for the X-ray flare – it was too bright and faded too quickly to be an explosive end to a star’s life, they argued. Instead the researchers believed the X-rays were released by the feeding frenzy of a 300,000 solar

mass black hole. The astronomers’ calculations suggest that the object the black hole was snacking on was a brown dwarf – a failed star – with a mass of between 14 and 30 times that of Jupiter, but in the paper reporting on the observations the astronomers also pointed out that it might have been smaller. In other words, the object may have been a large, rather unfortunate, extrasolar planet.

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WORLDS FROM THE CLOSEST TO THE COLDEST, THESE EXOPLANETS HOLD THE RECORDS FROSTIEST If there are aliens living on OGLE-2005BLG-390Lb they’re going to need some serious thermal underwear. At around –220°C it’s the coldest exoplanet we know of.

NEAREST

LIVING IN THE

FAST LANE

Part of becoming an amateur astronomer is learning your way around the sky and beginning to recognise the constellations as they come and go throughout the year. The constellations that are visible change as our planet orbits the Sun and so, naturally, it takes time and effort to get familiar with them. So spare a thought for any poor soul trying to get into stargazing on the exoplanet CoRoT-7b, a rocky world orbiting the star CoRoT-7. It’s thought to be around five times the mass of the Earth and lies roughly 500 lightyears away in the direction of the constellation of Monoceros. But what’s most spectacular about CoRoT-7b is how fast it goes round its star; it orbits CoRoT-7 at a breakneck pace of over 750,000km/h, meaning its year is a paltry 20.5 hours. And because CoRoT-7b is also perilously close to its parent sun, the surface temperature could reach over 2,000°C on the side of the planet that faces the star, while on the other side it would hover at a subarctic –200°C. So it’s little solace that you’d be able to have a birthday party every 20 hours or so. Incredibly, there are some exoplanets in the Galaxy that have even shorter years than CoRoT-7b. Recently astronomers using the Kepler space telescope uncovered two alien planets with orbital periods of less than 10 hours. Kepler-78b tears around its star in just 8.5 hours. And like CoRoT-7b, Kepler-78b’s proximity to its star means it is a spectacularly hot 2,700°C – so hot, in fact, that scientists think its surface is probably a seething mass of lava. However, the current record holder for orbital speed is a world called KOI 1843.03, which zips round its star in an astonishing 4.25 hours. S

The exoplanet Alpha Centauri Bb is our nearest celestial neighbour. At ‘just’ 4.37 lightyears away, it is the closest exoplanet to our Solar System. LONGEST YEAR You’ll have a while to wait for a birthday on Fomalhaut b. It has the longest orbital period (year) of any known exoplanet at around 870 Earth years.

TOASTIEST Kepler-70b gets the prize for the hottest known world in the Galaxy. Its dayside temperature is thought to be almost 9,000°C.

The forgotten space

SCRIVEN BOLTON DECEMBER 69

Scriven Bolton

Ray Emery pays tribute to Britain’s unheralded space artist

LEEDS A.S. ARCHIVE X 2

Þ Scriven made his images more realistic by combining plaster models, like the lunar surface seen here, with illustrated backgrounds

S

criven Bolton is a figure whose life and work deserves to be more widely known and better remembered. As the foremost British astronomical illustrator of his time, he influenced the artistic career of the famous American space artist Chesley Bonestell, as well as being an assiduous and enterprising amateur observer.

Thomas Simeon Scriven Bolton (he inherited his mother’s maiden surname and was always known as Scriven) was born in 1883 into a prosperous family at Yeadon, near Leeds. He and his siblings shared considerable artistic talents: two of his sisters were graphic artists and his elder brother was a cellist with both the Hallé and the Leipzig Gewandhaus orchestras.

Scriven’s father, Simeon Bolton, was a mill owner in Yeadon. At the time of Scriven’s birth the woollen textile business was thriving. Unfortunately, due to a recession in the early 1890s the mill was lost. But Simeon was able to take a part-share in a mineral oil merchanting business and, in time, the family were able to move to Waterloo Lodge, an out-of- > skyatnightmagazine.com 2013

70 < Jupiter’s Great Red Spot was once much larger than it is today, something clearly visible in this illustration from 1899

Þ Scriven used his observations of Mars to make this image of the Red Planet in October 1909 for the British Astronomical Association

CHAMBERS’ ASTRONOMY 1912 X 3, PRINT SCAN COURTESY OF OXFORD MUSEUM OF THE HISTORY OF SCIENCE; DIGITALLY RESTORED BY RAY EMERY, ELLISON HAWKS, “STARS”, PUBL. JACK 1910, ENGLISH MECHANIC NOV. 24TH 1922

> town villa in Bramley, Leeds. Scriven followed his father into the firm and it was at Waterloo Lodge that he built a large observatory housing his ‘Two-Foot’ Newtonian reflector. A confident young man, Scriven joined the Leeds Astronomical Society (Leeds AS) in March 1899 and the British Astronomical Association (BAA) at about the same time. He is also listed as being a member of the short-lived Astronomical Society of Wales and, in May 1905, was elected a Fellow of the Royal Astronomical Society (RAS).

Sketching the heavens Scriven displayed a gifted draughtsman’s hand at the telescope and by 1906 was sending drawings of Jupiter to Astronomer Royal William Christie. It was at about this time that Scriven gained entry to the world of astronomical and science illustration work, and he was soon producing partly imaginative (but scientifically respectable) artworks for well-respected periodicals. These titles included The Illustrated London News, The New York Times, Popular Science Monthly, Nature, The Sphere, The Graphic, Science and Invention, Amazing Life, Astounding, National Geographic and The Yorkshire Post. There were also numerous contributions to The English Mechanic, the Journal Astronomique de France and, of course, the publications of the BAA, the RAS and Leeds AS. He used a wide range of techniques to make his drawings, including pen and ink, pastels, paints and, later on, skyatnightmagazine.com 2013

Þ Scriven’s huge telescopes were easily capable of revealing the moons of Saturn and details in its cloud belts that can be seen in this illustration, dating back to 1910 photography. This range expanded to include commissions for science books by various publishing houses and authors. His contributions appear in Chambers’ Astronomy, Hutchinson’s Splendours of the Heavens, HH Turner’s A Voyage in Space and The Wonder Book of Science – 1946. No definitive list of his illustrations currently exists and they are still being found today. The scope of Scriven’s astronomical illustrations ranged from Earth and other bodies of the Solar System, out into deep space, as it was then understood. They also proved to be a big influence on the work of the legendary American space artist Chesley Bonestell. Bonestell, who had made his first astronomical painting in 1905, worked as

an architectural illustrator in the US, until the Great Depression put a halt to most construction work. He ended up in London in the early 1930s, working as an illustrator for The Illustrated London News, the same paper that had published many of Scriven’s astronomical illustrations. It was here that Bonestell first became aware of Scriven’s space art, and that Bonestell’s interest in astronomical illustration was re-awakened. Ron Miller, the American space artist, author and authority on Chelsey Bonestell, notes that Bonestell and Scriven shared an innovative use of three-dimensional plaster models in their artwork. Both of them would build and photograph these models as a basis for their illustrations in

SCRIVEN BOLTON DECEMBER 71

Þ Not realising that Jupiter’s features can change dramatically over a short period of time, Scriven attempted to depict the entire face of the planet during a course of seven months

Þ Scriven’s ‘Two-Foot’ Newtonian was the largest of the three telescopes installed in the Waterloo Observatory in Bramley an early 20th-century equivalent of what space artists do digitally today.

Studies of the sky As well as his prodigious illustrative skill, Scriven was also among that breed of keen amateurs who wished to make deductions from their observations. Although his opinions were sometimes critically received, his contributions

– mostly planetary and lunar studies in the early years – were regarded as valuable and worthy of notice. He carried these studies out on a number of quality telescopes, starting with a 4.125-inch refractor, with which he observed diligently and submitted full-rotation observations of Jupiter to both the BAA and Leeds AS. Rather charmingly, the drawing of Jupiter he made in the early 1900s (compiled from several months’ worth of observations) appears to assume that the various features would have remained essentially unchanged over this long period. Scriven later moved up to a 10.25inch With-Browning reflector. He was determined to get the most out of the

telescope and developed an innovative control system for the clock drive on its equatorial mount (see ‘The Waterloo Observatory’ below). He made extensive observations of Venus, or its atmosphere, at least. Believing that he could perceive subtle shadings on the planet, he deduced a rotation period of about 24 hours. He was incorrect, although his timing was in common with a number of leading visual observers so he was in good company. Scriven observed and drew whatever phenomena occurred in the sky above his hometown Leeds. Comets and the Northern Lights were well seen by him in the much darker skies of the time. In 1908 the University of Leeds made available its new Cecil Duncombe >

THE WATERLOO OBSERVATORY

Constructed in 1913, Scriven’s home observatory, pictured above, had a rotating dome that housed several telescopes. These included the large ‘Two-Foot’ Newtonian reflector (which actually had a 26-inch aperture), a 10-inch photographic reflector and a 6-inch Dallmeyer astrographic refractor. These instruments were all set on a single German equatorial mount, whose RA axis was fitted with an improved clock drive, to allow for better tracking of the stars. This

‘oil drive’ – a kind of regulator for a fallingweight mechanism – was first developed for Scriven’s 10.25-inch With-Browning reflector, with the help of a former Leeds AS president GH Denison. Scriven described this device in a 1922 issue of English Mechanic magazine: although the oil drive was “not perfectly regular” in its operation, it was good enough to be incorporated on the larger mount in the Waterloo Observatory. The mount’s largest telescope, the ‘Two-Foot’ reflector, had a focal ratio of around f/6. Scriven had the scope’s tube perforated with large holes to increase the airflow around the optics, as can be seen in the image on the right. This helped to reduce the time it took for the main mirror to reach thermal equilibrium – in other words, the same temperature as the outside air – and thus give him much steadier views of the sky. Although no trace of the observatory exists today, a replacement mirror for the ‘Two-Foot’ telescope survives somewhere in the West Midlands.

skyatnightmagazine.com 2013

72 SCRIVEN BOLTON DECEMBER

Scriven studies the Sun by projecting its image as it passes over Leeds

Þ Views of the Sun as it might appear if seen from Mercury, left, and the Moon, right

Þ Scriven’s observations of Venus’s cloud

markings, which he believed were its surface > observatory on Woodhouse Moor – within easy walking distance of Scriven’s home at the time. He was one of only two members of Leeds AS, along with Ellison Hawks, to be given time on the large 18inch aperture Newtonian under a mutual arrangement between the university and the astronomical society.

LEEDS A.S. ARCHIVE X 2

His efforts recognised Scriven was honoured with the award of the Gold Medal at the Franco-British Exhibition in 1908 and, in 1910, was presented with a Diploma at the JapanBritish Exhibition. In 1912 his lunar work was exhibited by the Astronomical Society of Barcelona as part of their International Exposition of Lunar Studies and by 1926 he was illustrating a book for the leading theoretical astronomer, Sir James Jeans. In November 1924 his artistic work was deemed to be of sufficient standing for him to be elected a Fellow of the Royal Society of Arts. His death, a little more than five years later, didn’t put an end to skyatnightmagazine.com 2013

> Scriven produced illustrations for many

publications to explain astronomical phenomena, such as sunspots, seen here

the accolades: on HP Wilkins’s huge map of the Moon of the 1950s, Scriven had a crater unofficially named after him. At the time of his unexpected death, Scriven was involved in a significant project. He had set out to determine, by photographic means, the light curves and spectral types of new variable stars, which he thought he had discovered in the Pleiades star cluster. Sadly, this work was not to come to fruition: on Christmas Day 1929 Scriven Bolton died of complications resulting from the influenza he’d been suffering with for three weeks. He was only 46 years old. Just nine days before he died, Scriven had received a letter from British film producer John Betts, who wanted him to illustrate what could have been the first ‘talkie’ film about astronomy to be made in the UK. Perhaps the last words about Scriven should be those written to his family by one of his many publishers, regretting the loss of “a man so talented and of so charming a character”. S

ABOUT THE WRITER Ray Emery is a past president of Leeds Astronomical Society, which holds a collection of Scriven Bolton’s papers and illustrations.

READER SURVEY Dear Reader, Welcome to our reader survey. We want to find out what you think of BBC Sky at Night Magazine and this survey is your chance to tell us what you’d like to see in your magazine in the future. The more we know about your interests, likes and dislikes, the more enjoyable and relevant we can make the magazine for you. Please go to www.skyatnightmagazine.com/readersurvey to complete the questionnaire. Alternatively, you can return the questionnaire here in a small envelope (no stamp required) to FREEPOST RRYY-HASZ-KJGU, Sky at Night reader survey, NSM Research Ltd, PO Box 354, Kidlington, OX5 9BR. Return the questionnaire to us by 11.59pm on 15 December 2013 and you’ll be entered into a prize draw to win a 16GB iPad mini worth £249. We look forward to hearing from you. Chris Bramley, Editor

17. Listed below, are all the sections that appear on the coverdisc with this issue of BBC Sky at Night Magazine. For each item please tick the column that comes closest to your opinion of it.

8. How often do you observe the night sky in the following locations? Regularly Sometimes Never 1 2 3 My back garden     Dark sky site locally     Dark sky site nationally     Dark sky site abroad     9. What is the main way you observe the night sky? Naked eye Binoculars Small scope (reflector <200mm, refractor <90mm) Large scope (reflector >200mm, refractor >90mm) 10. How would you rate your involvement in astrophotography? I don’t take astrophotos (go to question 12) Beginner Intermediate Expert

1 2 3 4

   

1 2 3 4

Did not access

7. On average, how frequently do you observe the night sky? Most nights 1 2-3 nights a week 2 Once a week 3 Once a fortnight or less 4 COVERDISC BBC Sky at Night TV programme Film room Eye on the Sky gallery Hotshots gallery Virtual Planetarium Software Observing forms Deep-sky tour chart Telescope software updates Astronomy societies list Archive magazine articles (PDFs) Get started guides (PDFs) Desktop wallpaper Glossary Equipment review guide BBC Sky at Night Magazine links

Not at all interesting

16. Which one of the following formats would work best for providing the monthly CD-ROM content to you? CD-ROM 1 Free digital download from BBC Sky at Night Magazine website 2 USB stick 3 Other (please specify).................................................  4

Not very interesting

6. In terms of practical astronomy, how would you rate your level of knowledge? Beginner 1 Expert 3 Intermediate  2

                 

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18. What do you think about Sky at Night Magazine’s coverage of the following subjects? Too much About right Not enough 1 2 3 Astronomy education   

Not at all interesting

Not very interesting

15. How important is the CD-ROM in your decision to purchase BBC Sky at Night Magazine? Very important 1 Not that important 4 Quite important 2 Not at all important 5 I’m ambivalent 3

1 2 3 4

                 

19. Listed below, in page order, are the regular sections that appear in this issue of BBC Sky at Night Magazine. For each item please tick the column that comes closest to your opinion of it.

1 2 3

Quite interesting

   

13. What is the main reason you do not view the CD-ROM more often? CD is incompatible/doesn’t work 1 Do not have access to a CD drive 2 I’m not interested in the content 3 I do not have enough time 4 It’s too much effort 5 Other (please specify).................................................  6 14. What do you do with the CD-ROM? Keep it Throw it away Pass it on to a friend

4. Which of these magazines do you also read? Regularly Occasionally All About Space 1 1 Astronomy 2 2 Astronomy Now 3 3 How it Works 4 4 New Scientist 5 5 Sky & Telescope 6 6 B. YOUR INTERESTS 5. Which of these best describes your relationship with astronomy? Interested, but don’t actively pursue It’s a hobby I actively pursue I study/studied it as part of a degree or qualification I work in the field

C. ABOUT BBC SKY AT NIGHT MAGAZINE 12. How regularly do you view the CD-ROM provided with BBC Sky at Night Magazine? Every issue (go to question 14) 1 Most issues (go to question 14) 2 Occasionally 3 Never 4

                 

Quite interesting

3. How many other people have read or looked at any of your copies of BBC Sky at Night Magazine for longer than two minutes in the last 12 months? Nobody else  1 Five 6 One 2 Six 7 Two 3 Seven 8 Three 4 Eight 9 Four 5 More than eight 0

Book reviews Cosmology Equipment reviews Ideas for events to attend Practical observing guides News What to see in the night sky Dark-sky observing locations Space exploration Manned spaceflight Exoplanets Astrophotography guides Astrophotography galleries History of astronomy Planets & the Solar System DIY equipment projects Astronomy on TV/radio Troubleshooting advice

Very interesting

2. On average, how long do you spend reading an issue of BBC Sky at Night Magazine? Under 30 mins 1 2-3 hours 4 30 mins to an hour  2 3-6 hours 5 1-2 hours 3 Over 6 hours  6

AN iPA M I NI

Did not read

1 2 3 4 5

11. What equipment do you use to take your astrophotos? CCD camera 1 High frame rate camera  4 Digital camera 2 Modified webcam 5 Film camera 3 Video camera 6

Very interesting

A. READING/BUYING/SERVICES 1. How often do you buy BBC Sky at Night Magazine? Always – I am a subscriber  Always – Every issue but don’t subscribe  Quite often – Once in every 2/3 issues  Occasionally  This is my first issue 

WIN D

ARTICLE 12345 Eye on the Sky  Bulletin  Cutting Edge – Chris Lintott  Cutting Edge – Lewis Dartnell  What’s on  The Sky at Night diary  Jon Culshaw’s Exoplanet Excursions  Interactive  Hotshots  The Sky Guide: This month’s highlights  50-51 The Sky Guide: 3 top sights  52-53 The Sky Guide: The planets  54-55 The Sky Guide: All-sky star chart  56-57 The Sky Guide: Deep-sky tour  58 The Sky Guide: Binocular tour  59 The Sky Guide: Moonwatch  60-61 The Sky Guide: astrophotography  78-79 Skills: The Guide  80-81 Skills: How To  82 Skills: Sketching  87 Skills: Scope Doctor  89-100 Equipment Reviews  102-103 Books  104 Gear  106 What I Really Want To Know...  PG 6 11-17 14 16 19 20-21 23 24-26 30-32 48-49

20. How much did you enjoy reading this issue of BBC Sky at Night Magazine? Very much  1 Not very much 3 Quite a lot  2 Not at all 4 21. Has reading BBC Sky at Night Magazine ever resulted in you… (please tick all that apply) Buying an advertised product 1 Buying a reviewed book 2 Buying a reviewed piece of equipment 3 Going online for information about a product 4 Going outside to look at the night sky 5 Going to a local observing event 6 Listening to/watching a programme 7 Staying overnight at a star party 8 Visiting the magazine’s website 9

skyatnightmagazine.com 2013

74 READER SURVEY DECEMBER 22. Which of the following words or phrases would you use to describe BBC Sky at Night Magazine? Accessible 1 Patronising 5 Boring 2 Up to date 6 Higher quality 3 Visually stunning 7 Informative 4

Gardening Meteorology Photography Travel Wildlife Other (please specify).................................................

     

0 1 2 3 4 5

D. WWW.SKYATNIGHTMAGAZINE.COM 23. How often do you visit the BBC Sky at Night Magazine website? More than once a day  1 Once a month Daily  2 Once a quarter A few times a week  3 Only visited it once Once a week  4 Never (go to question 26) 2-3 times a month 5

29. Are you a member of any of these national organisations? Please tick all that apply British Astronomical Association Local astronomy society The National Trust The RSPB Society for Popular Astronomy Other (please specify).................................................

     

1 2 3 4 5 6

   

6 7 8 9

24. How often do you access the following sections of the BBC Sky at Night Magazine website? Regularly Occasionally Never 1 2 3 Astrophoto galleries     Astrophoto tips     Hotshots gallery     Photo wall     Backgrounds     Image processing guides     Astrophoto guides     Podcasts     What’s on     Features     Beginners’ astronomy guides     Blogs     Book reviews     Equipment reviews     Forum     Interactive astronomy tools     Magazine     News     Observing guides     Patrick Moore columns     Polls     Quiz     TV & radio listings     Vodcasts     25. Which of the following content would you most like to see on the website? Please tick one box only in each column 1st preference 2nd preference Customisable star maps 1 1 Free ads for second-hand kit 2 2 3 More equipment reviews 3 Practical features 4 4 Subscriber area with extra content  5 5 Other (please specify below)  6 6 ................................................................................................ 26. Which of these websites do you use regularly? Please tick all that apply Astro Buy and Sell 1 Astro Chat forum 2 Cloudy Nights 3 Progressive Astro Imaging Group forum 4 Sky at Night Magazine forum 5 Stargazers Lounge 6 UK Astro Imaging forum 7 None of the above 8 27. Are you interested in reading a digital version of BBC Sky at Night Magazine on any of the following? Yes No PC/Mac 1 1 e-reader 2 2 Mobile phone 3 3 Tablet, eg iPad 4 4 E. TRAVEL AND LIFESTYLE 28. Besides astronomy, which of the following pursuits do you enjoy? Please tick all that apply Books/reading 1 Classic cars 2 Fishing 3 History 4 New technology/gadgets 5 Science fiction 6 Walking 7 Camping 8 Films/DVDs 9

THANK YOU FOR HELPING!

30. Have you attended one of these star parties/events in the last two years? Please tick all that apply Astrofest 1 Astrocamp (Brecon Beacons) 2 Autumn Equinox Sky Camp (Kelling Heath) 3 Herstmonceux Astronomy Festival (East Sussex) 4 International Astronomy Show 5 Kielder Forest Autumn Star Camp 6 Peak Star Party (Buxton) 7 South West Astronomy Fair (Sidmouth) 8 Spring Star Party (Kelling Heath) 9 Other (please specify) 0 31. Are you interested in tailored astronomy breaks? No – not interested Interested but never been on one Been once before Regularly go on astronomy breaks

   

1 2 3 4

32. Have you ever considered studying an astronomyrelated subject? Evening course 1 Part time 4 GCSE 2 No 5 Online learning 3 33. How much is your astronomy and astrophotography equipment worth? Astronomy Astrophotography Under £500 1 1 £500- £1,000 2 2 £1,001- £2,000 3 3 £2,001- £5,000 4 4 Over £5,000 5 5 34. How much do you intend to spend on telescopes and other astronomy equipment in the next year? Under £500 1 £2,001- £5,000 4 £500- £1,000 2 Over £5,000 5 £1,001- £2,000  3 35. Where are you most likely to buy astronomy equipment? 3 High street retailer 1 Mail order Internet 2 Specialist retailer 4 F. ABOUT YOU 36. Are you: Male 1

Female

2

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3 4

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5 6 7 8

4 5 6    

1 2 3 4

5 6    

7 8 9 0

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3 4

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78

Skills

Brush up your practical astronomy prowess with our team of experts

Contents The guide

How to

Sketching

Scope doctor

78

80

82

87

Was the Star of Bethlehem really a star, or something else?

Build a polar finderscope to complement an EQ1 mount

Learn how to sketch the craters and cracks of the Aristarchus Plateau

Steve Richards answers your astro equipment queries

SKILLS

The guide

THINKSTOCK X 4, LAURENT LAVEDER/SCIENCE PHOTO LIBRARY

With Emily Winterburn

The real Star of Bethlehem Could astronomy explain the apperance of the ‘star of wonder’

U

p and down the country, small children are dressing up as Mary and Joseph, as angels and shepherds, as wise men and of course, as the Star of Bethlehem. And in audiences at nativity plays across the land, the astronomically minded may idly ponder – which star might that have been? skyatnightmagazine.com 2013

All the Bible gives us is from the Gospel of Matthew (2:1), where we are told that the wise men, or Magi, saw ‘his’ star rising in the east, and so came east to find the king of the Jews. Current scholarly thinking suggests the Magi were from Persia. The Bible then goes on to tell us that the star ‘stood over where the

young child was’. The star is not mentioned in any other account of Jesus’s birth. For some, this has led to the conclusion that perhaps the star was metaphorical, a literary device, following the Jewish story-telling tradition of Midrash. Others however have looked for an answer in astronomy.

SKILLS DECEMBER 79

THE CELESTIAL SUSPECTS A CONJUNCTION OF BRIGHT PLANETS

A SUPERNOVA OR NOVA

A popular explanation is to see the Magi as astrologers, looking not for a bright star, but for an astrologically significant event. In this context, conjunctions of planets, especially those involving Jupiter – the king planet – are popular. A very bright conjunction of Jupiter and Venus in Leo in June 2BC is one option, though a little late. Another is a conjunction calculated by Johannes Kepler, between Jupiter and Saturn in 7BC; another still has been identified between Jupiter, Saturn and Mars in 6BC. However, in both of these conjunctions the planets are not so close as to be described as a single star.

Early Western astronomers believed the ‘fixed stars’ to be unchanging and simply didn’t recognise events such as supernovae until the 15th century. Not so with their Eastern counterparts, who recorded a ‘supernova’ in Capricornus in 5BC that stayed visible for 70 days and another near Altair in Aquila in 4BC. Today there is doubt that either were actually supernovae, since no remnants have been found, but they could have been variable stars. Scholars think the Magi probably came from Persia, in which case the first fits their description of a star rising in the east at dawn.

A COMET

A STATIONARY POINT OF JUPITER

A comet is perhaps the most easily imagined candidate for the star of Bethlehem, especially when you consider that one of the first sightings of Halley’s Comet (observed by Chinese and Korean astronomers) occurred in 12BC. Add to that a few more comets visible over the intervening years, and it would seem the puzzle was over. That is, until you consider one very important perception: in pretty much every culture around the world, comets have been traditionally considered symbols of bad news or bad omens. That would seem an odd sign for the Magi to follow.

Jupiter and Earth orbit the Sun in the same direction, though Jupiter moves much slower than we do. From Earth we mostly see Jupiter moving east to west Stationary point against the background stars, however, because of our relative speed and position, Jupiter sometimes appears to us to be moving backwards (retrograde) – heading east instead of west. The stationary point is the period between, during which Jupiter appears to be moving neither east nor west. While it’s quite possible that Jupiter was at its stationary point at the right time, it’s difficult to imagine why the Magi would find this significant since it happens every year.

One of the draws of an astronomical explanation is that astronomy is a great tool for dating ancient events. Just as we can predict when eclipses, conjunctions and comets are expected in the future, so too can we work backwards and calculate when they happened in the past.

Hidden clues There are limits to this method, mainly related to how we interpret the original text. Is the text definitely talking about an astronomical event and if so, what do they mean by their description? This means we can work out when to look, but may never be sure we’ve found the star. Precise dates aren’t given in religious texts, but we can work out some from the astronomical events named and events described elsewhere.

Stationary point

A census is mentioned in the nativity. We can estimate from Roman records that this was probably the census announced in 8BC and can conclude that data was collected for a few years after that. The Bible tells us that King Herod died shortly after a lunar eclipse and that Jesus was at least two when the king died; astronomers and theologians have identified an eclipse in March 4BC as the best candidate for this event. The biblical account also tells us that the star ‘stood over’ the young child. So we’re looking for a star – or some other astronomical event – rising in the east around 6BC that appeared stationary over Bethlehem. In the box above, we take a look at the prime suspects. Dr Emily Winterburn is a science historian and museum curator

WILL WE EVER KNOW FOR SURE? The Star of Bethlehem’s true identity has puzzled and fascinated, and doesn’t look in any danger of losing its appeal. A couple of lines in the Bible have produced endless possibilities and new theories keep on coming. Astronomer Michael Molnar recently suggested the answer might lie in the astrologically significant double occultation of Jupiter by the Moon in Aries in 6BC. Mark Kidger, author of The Star of Bethlehem, alternatively identifies a variable star in Aquila coupled with an astrologically significant conjunction of Jupiter and Saturn in Pisces. Will we ever know? It’s doubtful, but still fun to ponder. S

skyatnightmagazine.com 2013

80

SKILLS

How to

Build a polar finderscope With Mark Parrish

Get more from an equatorial mount with this simple accessory

TOOLS AND MATERIALS

FINISH

Spray paint to suit the colour of your mount. MATERIALS

A short length of tube for the main body (ours was 200mm long and 22mm in diameter, but this depends on the lens); small offcuts of timber for base; a small amount of stiff card and some foil. SUNDRIES The finished article ready for use – give it a coat of paint and you can barely tell that it’s home-made

ALL PICTURES:MARK PARRISH

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any of us start out with a small telescope that is often bundled with a simple equatorial mount. These budget mounts offer some of the advantages of their more expensive stablemates – making it easy to deal with the apparent movement of the night sky as you view objects in the eyepiece, for example. But poor instructions and minimal features often lead to frustration and improper use. In this month’s How to, we show you a way of making a simple accessory to polar align a very basic equatorial mount and make it easier to set up. The project involves building and attaching a red-dot finder to the main body of the mount. This is a small device that uses an LED, a tiny pinhole and a lens to produce a dim, focused red dot when you look into the tube. By keeping both eyes open, simultaneously looking into the tube and skyatnightmagazine.com 2013

at the sky beyond, your view of the night sky will appear to have the red dot superimposed upon it. This is the key to helping you to correctly align the mount, which is vital if you are to get the best out of it.

Polaris beckons The German Equatorial Mount is a long-established design that utilises two axes of rotation. Unlike an altaz mount, which has to be adjusted left-right and up-down to compensate for Earth’s steady rotation and so keep your scope pointed at a given target, the GEM mount only requires adjustment in one axis when correctly aligned. This means you can slowly turn a single knob or, in some cases, use an electric motor to keep the target centred in the eyepiece. You can then also use celestial coordinates to locate objects in the sky with the aid of graduated discs on the mount called setting circles.

A convex lens with a focal length of 50-150mm, red LED, toggle switch, 3V coin cell battery (we used a CR2032) and holder, solder, a short length of wire, jubilee clips or cable ties. TOOLS

A coping saw or similar, drill, sandpaper, ruler, compass, pencil, scissors, glue and a soldering iron.

For this to work, the main (polar) axis must align with Earth’s axis of rotation. Fortunately for observers in the northern hemisphere, this is very close to Polaris, the pole star. More expensive mounts have an internal alignment telescope to help point in this direction, but budget versions don’t. This is where our polar finder comes in. After positioning your mount, you can use the mount’s adjustment screws to aim the finder’s red dot as close to Polaris as you can. Once aligned you can slew your telescope onto the desired target and begin

SKILLS DECEMBER 81

STEP-BY-STEP GUIDE

The finder tube push fits into the base. Make sure you attach it the right way up, lens down

observing. You should then find you can keep the object in view for long periods of time by slowly turning the slow motion control.

Assembly time We used copper plumbing pipe for our finder tube. You could buy a lens, but you may be able to scavenge one from an old eyepiece or, as we discovered, a child’s magnifying glass – although this did require quite a long tube. You may need to experiment to determine the focal length and hence the distance between the lens and the pinhole – see the step-by-step guide on the right. Make the polar finderscope by following the rest of these steps, using the plans on this month’s coverdisc to help you – there are diagrams to cover testing the lens, tube design and the wiring layout. Attaching the finder’s base to your mount may require a little ingenuity, but all the mounts we examined had a suitable cylindrical surface on which to clamp the base using a jubilee clip or cable ties. Now it’s time to slot in the finder itself. The lens is the part you look into, hence it points downwards towards the ground and you. As you look up towards the sky, with one eye taking in the image of the red dot through the lens and the other the background sky, the effect is seen as a red dot appearing in the sky. You can’t see through the tube because the electronics are blocking the end, of course, but with both eyes open, your brain is able to combine the view from each eye. One final tip: the first time you polar align your equatorial mount using this accessory, make sure you mark out the position of your tripod’s feet. This will help you get set up a lot quicker in subsequent sessions. S Mark Parrish is a consummate craftsman who loves making astro accessories

STEP 1

STEP 2

STEP 3

STEP 4

STEP 5

STEP 6

Use offcuts of wood to make a test rig. Support the lens so it remains upright and focus the projected image of a distant object (like a tree) onto a piece of paper. Measure the distance between the lens and the image – this is the focal length.

The light housing is made from rolled up card, which simply slides into the main tube. The LED is held by a cardboard disc; in front of it is another, foil covered cardboard disc with a pinhole in it. The switch fits into a separate end plug, made of two cardboard discs.

The base is made from two rectangular offcuts of thin wood with a central spacer the same width as the diameter of your tube (22mm in our case). It should be glued together upside down so that the tube, the top of the spacer and sides are all parallel.

Solder together the circuit for the LED – refer to the simple wiring diagram on the coverdisc. Use short lengths of flexible wire between the parts as above – this will make it easier to move them into suitable positions inside the light housing, which we’ll work on next.

Spray the tube in a colour to suit your mount. Glue your lens to the end (if using one from a magnifying glass like us, cut it to size first). Insert the assembled lighting unit and adjust until the distance between the pinhole and the lens is the same as you noted in Step 1.

We drilled a hole through the base and used a jubilee clip to attach it to the mount. The tube of the polar finderscope simply pushes into the base when you need to use it. If you want to attach it permanently you could drill more holes and use cable ties.

skyatnightmagazine.com 2013

82 SKILLS DECEMBER

SKILLS

Sketching The Aristarchus Plateau

With Carol Lakomiak

NEED TO KNOW STEP 1 With an HB pencil, roughly sketch the main features of the plateau, including where the deep shadows are – use a light touch so corrections can be made. Fill the shadows with a 9B pencil, blend them with a blending stump, then clean the stump on a piece of sandpaper.

NAME: The Aristarchus Plateau TYPE OF OBJECT: Lunar feature CONSTELLATION: Moon is in Taurus on the suggested night EQUIPMENT: 4-inch telescope or larger; H, HB, 9B pencils; blending stump; hard and kneadable art erasers; small piece of medium sandpaper BEST TIME TO SKETCH: Evening of 14 December FIELD OF VIEW SHOWN: 300x322km; 226x magnification

ALL PICTURES: CAROL LAKOMIAK

L

ocated on the Moon’s northwest quarter is an elevated block called the Aristarchus Plateau. On the southern edge of this region are two craters, Aristarchus and Herodotus. Aristarchus has a central peak and dark radial bands (often referred to as spokes) in the bright terracing of its western inner wall. It is the brightest crater on the Moon, and can easily be seen glowing in earthshine. Crater Herodotus, on the other hand, is quite dark and smooth because of the lava covering its floor. Just above Herodotus is a volcanic crater known as the Cobra’s Head. Schröter’s Valley snakes north from this feature, then veers southwest before fading at the plateau’s western edge. Just northwest of the plateau are the Agricola Mountains. These are not actually part of the plateau, but make a good border for your sketch. First, make a rough drawing of the plateau’s main features and then mark the location of the deep shadows. The shadows are constantly on the move, so for accuracy’s sake it’s best to record their positions within 10 minutes or so. If you normally rest the skyatnightmagazine.com 2013

heel of your hand on the paper as you sketch, put another piece of paper under your hand to avoid smudging the graphite. Like the rest of the lunar surface, the plateau contains many shades of grey in addition to its black shadows and white regolith. The darker shades of grey on the plateau are easily recorded by using an HB pencil, and varying the pressure you use. For the lightest grey areas, we’ll be using an H pencil – it’s a bit harder as it has a slightly higher clay content than the HB. In Steps 2 and 3, we’re going to place the graphite on top of the paper’s texture, then push it into the lower layers with the blending stump. This makes the graphite appear darker after blending, so use a light touch when applying the shading graphite. Finally, lunar libration gently makes the Moon ‘rock and roll’, bringing features closer to or farther from the visible lunar limb. So don’t be concerned if the plateau looks different on the sketch night to what’s shown here. Carol Lakomiak is BBC Sky at Night Magazine’s sketching expert

STEP 2 Using the flat edge of your HB pencil, place a layer of graphite where the plateau’s grey colour is darkest. Repeat the process where the grey is a bit lighter using a bit less pressure. Blend the lighter area before the darker one, then clean the stump.

STEP 3 Apply and blend H graphite to the plateau’s lightest grey areas using the same technique as in Step 2. At this point, you can also make any shading adjustments: to darken an area, add more graphite; to lighten it, dab graphite from the sketch with a kneadable eraser.

©

DAVID NOTON

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SKILLS DECEMBER 87

SKILLS

Scope

With Steve Richards

DOCTOR

Our resident equipment specialist cures your optical ailments and technical maladies

Over the years I have collected many lenses that no longer fit modern cameras. Is it possible to refurbish or adapt these to use them on new DSLRs or CCDs? DANNY VANDEGHINSTE

< Olympus OM

lenses can be fitted to newer DSLRs with the right adaptors

STEVE’S TOP TIP sture from

What’s the best way to prevent moi building up while out observing? sutovIf you use a Schmidt-Cassegrain, Mak during later or er Cassegrain or a refractor, soon front the on form will dew ion your observing sess even can it s ition cond p dam y reall lens – and in n reflector. form on the mirrors of a Newtonia thwhile wor a e A long dew shield can mak e. Buy mak to easy very are difference and they and size to it cut mat, ping cam a cheap foam tape. duct g tape it together into a cylinder usin t of fron the nd arou Finally, attach the cylinder band. tic elas an with it in reta your telescope and

I’m trying to image Jupiter with a Canon EOS 600D DSLR on a Celestron 9.25-inch SchmidtCassegrain telescope, but the image is tiny. Can you help me understand image size?

STEVE RICHARDS, STEVE MARSH X 2

CHRIS HIGGINS

Although lens technology continues to develop, many older camera lenses have very fine optics that can be pressed into service for wide-field astrophotography with modern DSLRs and CCDs – although there are some limitations that you need to consider. Although imagers covet fast scopes (those with a low focal ratio), there are issues involved when using camera lenses of any age at full aperture, as star shapes at the edges of the field of view can be quite adversely affected. It is much better to stop a lens down a couple of stops – this will improve the image dramatically, though it will create diffraction spikes, a side effect

generated by the leaves of the lens’s iris. Many older lenses have external adjustment rings for setting the aperture, which can be very useful as modern lenses don’t have this facility; their apertures are controlled electronically. You mentioned Olympus lenses in particular: an adaptor to convert an Olympus OM lens to either a Canon or Nikon bayonet fitting costs between £10 and £20. The same lens can also be attached to a CCD camera by first using an OM to Canon adaptor, then coupling the adapted lens and CCD camera together using a Geoptik T2 Adaptor for Canon EOS lenses. Whatever old lenses you have to hand, make sure that you examine them for fungal growth before anything else, as this can be a serious problem.

This is a common problem that catches out many new lunar and planetary imagers. There is nothing wrong with your system as such, it is all down to sensor size. The wonderful, close-up images that you see of planets like Jupiter are taken with high frame rate video cameras with small sensors. When these images are reproduced on the computer screen and the whole field of Þ High frame rate video cameras are commonly view is viewed pixel for used to capture pixel, the planet looks much planetary images more impressive than the much larger field of view of the DSLR camera zoomed out to fit the screen. If you were to display the DSLR image at 100 per cent size, centred on the planet, you’d have a fairer comparison. To get the best out of your combination, use your Canon EOS 600D in video mode, but set the movie recording size to 640x480. Then use stacking software, such as RegiStax, to convert the movie into a single high-resolution image. Steve Richards is a keen astro imager and an astronomy equipment expert

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

UNIVERSALLYSUPERIOR

A SOLID FOUNDATION

DESIGNED FROM THE

12031 – Advanced VX 8 EdgeHD Camera not included

Engineered from the ground up with astroimaging in mind, the new Advanced VX series from Celestron sets a superior standard in mid-level telescopes. Advanced VX provides you with many of the features found on Celestron’s most sophisticated German equatorial mounts, at an extremely affordable price.

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REVIEWS DECEMBER 89

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

90

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

N EW

Find out how Takahashi’s imaging Cassegrain fares when pitted against the great British weather

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

WWW.THESECRETSTUDIO.NET X 4

This month’s reviews

First light

90

Takahashi CCA250 corrected Cassegrain astrograph

94

William Optics ZenithStar 71 ED doublet refractor

Tried & tested Books

Gear

98

104

Mallincam Xtreme colour video CCD camera

102

We rate four of the latest astronomy titles

Including this starter set of four eyepieces

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

90

FIRST light

Cassegrain astrograph A mighty 10-inch imaging scope that stays cool under pressure WORDS: STEVE RICHARDS

VITAL STATS s Price £13,079 s Optics Corrected Cassegrain s Aperture 250mm (10 inches) s Focal Length 1,250mm, (f/5) s Focuser Motorised, moving secondary mirror s Extras Losmandy compatible dovetail rail, 7x50 illuminated reticule finderscope, toolkit s Length 870mm, including dewshield s Weight 22.8kg s Supplier Green Witch s www.green-witch.com s Tel 01767 677025

C

assegrain telescopes come in a range finish. A silver-finished top bar for support and a of designs – beyond the classic, the matching base support with a built-in Losmandyvariants include the Schmidt-Cassegrain, style dovetail bar complete the ensemble. Maksutov-Cassegrain, Ritchey-Chrétien Turning to the rear of the telescope, there is no and Dall-Kirkham. But what these external focuser as an electric motor designs all have in common is that their moves the secondary mirror towards SKY SAYS… internal reflecting surfaces direct light or away from the primary mirror to Conditions were out of the rear of the telescope through achieve focus. There is, however, a not ideal, but we rotatable connection port in the centre a hole in the primary mirror. Primary mirrors like this are known as of the back-plate for mounting were delighted Cassegrains after their 17th-century by the star shapes accessories, such as imaging cameras inventor, Laurent Cassegrain. This and star diagonals, using a wide range and colour that design produces a folded light path that of optional adaptors. This connection we captured results in a long focal length contained port can be spun through 360 º. within a short tube length. Our review telescope came already The Takahashi CCA-250 is based on the classic set up with the correct spacing adaptors needed to Cassegrain, although the CCA in its name stands for attach a DSLR, but a simple 1.25-inch eyepiece ‘corrected Cassegrain astrograph’, which means adaptor was also supplied. Completing the back there’s a correcting lens in the final stage of the light plate are three miniature cooling fans and a small path. Describing the telescope as an astrograph control module that houses two buttons for focus indicates that it is designed with imaging in mind. adjustment, a single button to turn on the fan, a USB connector and a 12V input socket, which powers the focuser and fans from an external power supply. After a one-hour cooling down interval with This unusual and substantial telescope is beautifully the automatic cooling system in operation, a star built in typical Takahashi fashion. The main tube test confirmed that the CCA-250 was perfectly assembly is manufactured from carbon fibre with a collimated. When we powered it up the focusing contrasting green-grey aluminium back plate and system completed an alignment cycle, but we had a front ring that supports the rolled-lip aluminium to gently pull a small shroud surrounding the dewshield. The interior of the telescope has an secondary mirror into place before the focus > exceptionally good matte black, non-reflective

Style icon

WWW.THESECRETSTUDIO.NET X 5

A FLAT LOT OF GOOD Whereas the ever popular Schmidt- and Maksutov-Cassegrain telescopes have a correcting lens element at the front of the telescope which also holds the secondary mirror, Ritchey-Chrétien, Dall-Kirkham and classic Cassegrains like the CCA-250 are open at the front and have a spider vane that supports the secondary mirror. On the CCA-250, light enters from the front of the telescope and passes down the tube where it is reflected back by the 10-inch wide, f/2.75 parabolic primary mirror. This light is

skyatnightmagazine.com 2013

then reflected back down the tube once more by the 5-inch spherical secondary mirror, where it is corrected by an 3-inch, three-element correcting lens. This lens is designed to produce a very flat field of focus, which is important if you want to avoid the distorted stars at the edges of the field of view – a common feature of reflecting telescopes. In our tests, star shapes were excellent right to the edge of the field of our Kodak KAF-8300’s 22.5mm diagonal sensor with no false colour around bright stars.

FIRST LIGHT DECEMBER 91

COMPUTERISED COOLING There are three computer-controlled fans on the rear plate. Temperature is monitored by three sensors: one monitoring the ambient air, another the primary mirror and the last the tube. These work in unison with the fans to maintain a stable overall temperature.

ELECTRONIC FOCUSING DEW SHIELD The permanently attached, 260mm-long aluminium dew shield does an excellent job of protecting the secondary mirror from dewing over and helps to keep stray light at bay. Like the carbon fibre tube itself, the interior is finished in a very good matte black to further counter stray light and increase contrast.

The unusual focusing system uses a microstepping motor to move the secondary mirror. Focus can be adjusted using two push buttons on the rear panel of the telescope, or by clicking on the relevant direction button in software using the supplied ASCOM driver. Achieving accurate focus manually was also simple using this system.

CARBON FIBRE TUBE The main tube is made from carbon fibre, which not only reduces the telescope’s weight, but also introduces a level of thermal stability not possible with an aluminium or steel tube. Using this material combats tube expansion through temperature change, resulting in more consistent focus during an imaging session.

skyatnightmagazine.com 2013

92 FIRST LIGHT DECEMBER

FIRST light FINDERSCOPE The CCA-250 is supplied with a 7x50 illuminated reticule finderscope that can be attached to one of two locations on the rear of the telescope with a single large bolt. This attachment allows you to choose a wide range of positions to suit your requirements. Making adjustments to align the finder with the telescope is also simple.

> system would operate using the push buttons.

After this, focusing was quick and smooth although we would have preferred a small, wired hand controller to adjust focus rather than having to make adjustments by pressing the two buttons on the rear of the telescope. The Takahashi CCA-250 ships with an ASCOM driver for full auto focus, but this was not compatible with our version of MaxIm DL so we were unable to test it.

> The Great Globular

Cluster in Hercules, imaged with LRGB filters

< The Dumbbell Nebula in Vulpecula, imaged in Ha and OIII, plus luminance

WWW.THESECRETSTUDIO.NET, STEVE RICHARDS X 2

Eyes on the skies Although designed for astro imaging, we wanted to try the CCA-250 as an observing tool and it doesn’t disappoint when used in this capacity. An early morning opening in the clouds gave us the opportunity for some fine observing. The telescope showed the Orion Nebula’s Trapezium region beautifully in our 5mm eyepiece and a huge swathe of nebulosity in our 24mm eyepiece. Open clusters M34, M36, M37 and M38 were stunning; turning to Jupiter, the seeing wasn’t good enough to handle the 250x magnification of our 5mm eyepiece, but the planet was a fine sight in our 8mm one, especially so with an unplanned straight-line alignment of the Galilean moons. But, this scope is an astrograph so we happily replaced our eyepieces with our QSI 683WSG CCD camera. We captured images of the Great Globular Cluster in Hercules in LRGB and the Dumbbell Nebula in narrowband using hydrogen-alpha and Oxygen III filters, to assess skyatnightmagazine.com 2013

colour correction and field flatness. Although sky conditions were not ideal during the review period, we were delighted with the star shapes and colour that we captured. The CCA-250 is aimed at advanced deep-sky imagers with a permanent observatory and stargazers in this bracket won’t be disappointed with this telescope. S

VERDICT BUILD AND DESIGN EASE OF USE FEATURES IMAGING QUALITY OPTICS OVERALL

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

SKY SAYS… Now add these: 1. EM-500 German equatorial mount with Temma-2 control system 2. SXVR-H36 monochrome CCD camera 3. Takahashi heavy-duty tripod

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Baader Classic Q-Eyepiece Set Classic eyepieces: 6mm, 10mm, 18mm Ortho and 32mm Plossl, Q-Barlow 2.25x, Q-Turret quad eyepiece revolver, Astro Box #1

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94

FIRST light William Optics ZenithStar 71

ED doublet refractor A remarkably short instrument that dispels the notion of a ‘typical’ scope WORDS: PAUL MONEY

VITAL STATS s Price £369 s Aperture 71mm (2.8 inches) s Focal length 418mm, f/5.9 s Optical design Air-spaced doublet s Focuser 2-inch rack and pinion dual-speed with microfocuser s Length 310mm, 355mm with dew shield extended s Mounting L-type bracket s Weight 2.7kg s Extras 2- to 1.25-inch adaptor s Supplier Widescreen Centre s www.widescreencentre.co.uk s Tel 020 7935 2580

SKY SAYS… The field of view was good across 85 per cent with only slight trailing off towards the field edge

R

efractors are the ‘typical’ telescope first-time stargazers tend to associate with looking at the night sky; the image they imagine is usually one of a long tube with the eyepiece at the end. But improvements in manufacturing and grinding techniques have led to shorter focal length lenses with good colour correction – dramatically shortening the length of the tube required. Following in this tradition is the latest scope from William Optics, the ZenithStar 71 ED, a doublet refractor just 310mm long. The ZS71 ED has a 2.8-inch, air-spaced and fully multicoated doublet objective lens made from Ohara ED glass. This lens has a short focal length of 418mm, giving a fast focal ratio of f/5.9, which is ideal for imaging. The scope also features a retractable dew shield – when extended, this increases the scope’s overall length to 355mm. At the other end, the focuser back can be fully rotated and has a locking screw that firmly keeps it in place when set in the desired position. We did notice a little play when our Canon EOS 50D DSLR was attached and found that it was best to recheck the focus after rotating the back section. This is a minor quibble, however: we found we could quickly refocus and then continue with our imaging tests. The focuser itself is a dual-speed rack and pinion design and has a generous 80mm of travel. The telescope comes with a 1.25- to 2-inch adaptor and an L-style mounting bracket, which allows the scope to be used on a photographic

WWW.THESECRETSTUDIO.NET X 4

OPTICS The objective lens is made from Ohara ED (extra dispersion) glass and all surfaces are multicoated. The doublet design corrects for chromatic aberration and visually, gave good views of the sky. Photographically, there was slight colour fringing on the brightest stars, but this was a minor issue.

DEW SHIELD The retractable dew shield was smooth to use and easy to retract for storage after use. It gave decent protection from dewing up under normal conditions and did a good job at cutting out extraneous light as well.

skyatnightmagazine.com 2013

tripod. It’s also easy to attach to a Vixen-style mount for long imaging sessions or visual observations. We were also loaned a William Optics field flattener designed for short focal length instruments for our review.

Cut a wide swath We used a trusted 26mm eyepiece and star diagonal to check out the field of view, which was good across 85 per cent with only slight trailing off towards the field edge. Chromatic aberration – where not all the colours are brought to the same focus – was well controlled, so we sought out a couple of double stars to test the resolution. This is a wide-field instrument, so we added a 5x Powermate to the 26mm eyepiece to boost magnification to 80x and enjoyed good views of Albireo in Cygnus. Keeping the Powermate >

FIRST LIGHT DECEMBER 95

OPTICAL VERSATILITY Cheap, small refractors often put people off, but today’s short focus models are a long way from their ancestors and can be used for a wide variety of purposes. The ZS71 ED is light enough for you to use on a photographic tripod, either as a visual system or an imaging one, for casual astronomy or nature studies. Along with its low weight, it is quite compact and can therefore be taken abroad in airline hand luggage, making it a good travel scope when in search of distant

dark skies. Alternatively, adding a white light filter can turn it into a scope for eclipse chasers. It is also good as a wide-field imaging system, especially when combined with the optional flattener, and we were impressed with our test images of the Andromeda Galaxy and the Pleiades star cluster. The compactness also makes the ZS71 ED ideal as a lightweight guidescope – in a single word, versatility best sums up this telescope.

FOCUSER The focuser is a dual-speed rack and pinion design with a microfocuser for fine focus control. It was smooth in use and can be easily locked in place once focus is achieved, although there was a little image shift. It accepts 2-inch eyepieces as standard, but an adaptor for 1.25-inch eyepiece is supplied.

BODY The tube is quite lightweight and easy to handle at 2.7kg, but it is still robust. It is 310mm long, extending to 355mm when the dew shield is in use. The internal matte coating does a good job in cutting down on reflections within the tube, which can spoil the contrast in faint deep-sky objects.

skyatnightmagazine.com 2013

96 FIRST LIGHT DECEMBER

FIRST light

ROTATABLE VIEW The back section of the tube can be rotated through 360º and has a locking screw to hold it in place. This is a useful feature, but we did notice more play than we’d have liked, which meant we did have to refocus, especially when imaging.

SKY SAYS… Now add these: 1. William Optics 0.8x reducer-flattener

3. William Optics 90°, 2-inch quartz dielectric star diagonal

> The Andromeda Galaxy, imaged without the loaned field-flattener

> Composite image of the Pleiades open star cluster in Taurus

> but switching to a 9mm eyepiece, giving

232x magnification, we could nicely split Alpha Piscium. Its component stars are separated by a mere 1.8 arcseconds. Using our 26mm eyepiece again, we located galaxy pair M81 and M82, despite their small apparent size in the approximately 3º field of view. The size of the field meant we could nicely fit Orion’s belt in the view plus Sigma Orionis. Large bright objects are ideal targets for this

instrument, something we clearly saw with the Andromeda Galaxy, which appeared in the guise of a glorious haze with a large central bulge. Star clusters such as the Pleiades sparkled in the view, as did the myriad delights that could be spotted along the Milky Way. We were impressed with how well the telescope could bear higher magnification on many of these objects. This was also evident when we spotted Jupiter rising, so we pushed the magnification with the 9mm eyepiece and 5x Powermate and could easily see the two main bands and the Galilean moons. Later we also enjoyed the craters of the Moon – visually, this is a very capable telescope. Attaching our Canon EOS 50D DSLR, we imaged the Andromeda Galaxy by taking 32, 120-second exposures at ISO 800 and stacking them. This captured plenty of detail in the spiral arms, but as expected there was some distortion of stars at the image edges. We repeated the exercise with the loaned field flattener, which left stars pin-sharp all the way to the edge. The ZS71 ED is a lovely wide-field instrument that gives good results both for visual and imaging needs. S

VERDICT BUILD AND DESIGN EASE OF USE FEATURES IMAGING QUALITY OPTICS OVERALL skyatnightmagazine.com 2013

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

WWW.THESECRETSTUDIO.NET, PAUL MONEY X 2

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98

TRIED & tested

www.skyatnightmagazine. com/360/macx

We review well-established equipment that’s stood the test of time

VITAL STATS

WWW.THESECRETSTUDIO.NET X 4, MARK PAYNE-GILL X 3

s Price $1,499.95 s Sensor Sony ICX 418 s Sensor dimensions 795x596 pixels (PAL) s Telescope connection C-threaded 1.25-inch nosepiece s Ports Composite and S-video, aux, 12V power input s Dimensions 100x50x50mm s Weight 300g s Software Mallincam s Supplier Jack’s Astro Accessories s www.mallincamusa.com s Tel +1 985 863 2165

SKY SAYS… The camera is optimised for live viewing and pushes the boundaries of what is possible with a video sensor

Mallincam Xtreme

colour video

CCD camera N Bring the skies to life with stunning video footage WORDS: MARK PAYNE-GILL

ot long ago the possibility of enhancing what is visible through a telescope with deep-sky video astronomy would have seemed far-fetched. But a few products have appeared on the market claiming to do just that – and in colour. No computers, no image processing, just a video camera and TV with instant live results. One such product is the Mallincam Xtreme, a dedicated deep-sky astro video camera that is also capable of shooting solar, lunar and planetary objects. It’s compact and solidly built. The circuitry and software have all been designed with customised features optimised for astronomical use, pushing the boundaries to the extremes of what a video sensor can record.

Roll cameras We tested the Xtreme using a Meade 14-inch RCX telescope connected to a domestic 19-inch TV monitor and targeted some iconic Messier objects. It is crucial to set focus on a bright star after powering up the camera, as an unfocused image around a deep-sky object will just leave you looking at a blank monitor.

For deep-sky filming the Xtreme circuitry features a Peltier cooler, which mildly lowers the temperature of the 0.5-inch video sensor. This feature is unique to Mallincams and is included to reduce electronic noise and speed up acquisition times. Setting up is relatively straightforward. The camera is controlled by the five menu buttons on the back. Pushing the middle menu button activates the menu on a connected monitor. The other buttons navigate around the options and change the various settings. One minor criticism is that the onscreen menu could do with a more descriptive guide than the one supplied. An explanation of all the abbreviations would be really helpful. Once set up the most important settings are the integration time (‘Sense Up’), gain (‘AGC’) and contrast. Adjusting these will be enough to start acquiring views of deep-sky objects. Adjusting the gain to change sensitivity activates a safety timer for up to two minutes; it’s an automatic procedure that protects the sensor from overloading while the circuitry refreshes. During this time, functions shut down and the screen will go blank until the image with the new settings is integrated. >

OWNER’S OBSERVATIONS Name Mark Payne-Gill Location Chew Magna, Bristol Equipment Mallincam Xtreme colour video CCD camera Owner since January 2011 I’ve owned a Mallincam Xtreme for nearly three years and have used it on a variety of scopes from my 14-inch RCX Meade right down to 3-inch apo refractors – and it produces wonderful live views. Although twice the price of other astro video cameras, this one stood out thanks to its versatility and the features it has that aren’t found on other products, particularly the top-grade sensor, extended

skyatnightmagazine.com 2013

integrations and Peltier cooling. Mallincam also gives great online support, which went a long way towards helping to understand the camera’s features and operations not covered in the manual. A 0.5x focal reducer was a necessary addition to my kit to offset the high magnification of the small chip, along with external cooling fans to further increase the sensor’s performance. I’ve also added a flip mirror system to aid object locating and centring. With this I can effortlessly switch between eyepiece and live camera views. It’s great fun watching the faint, fuzzy blobs transform into picture-book images on a TV screen.

TRIED & TESTED DECEMBER 99

SOFTWARE Functions can also be controlled by computer using the included Mallincam software, with modes for deep-sky, lunar, planetary and solar observing. Footage can also be captured to computer with a suitable frame-grabber device. Software with more advanced features to extend the Xtreme’s capabilities can be purchased separately.

SENSOR At the heart of the camera is a 0.5-inch Sony ICX series sensor with 795x596 pixels, available in both NTSC and PAL versions. It gives views that approximate to a 9mm eyepiece. A Sony EXview HAD sensor with 40 per cent more sensitivity is also available.

PORTS Composite and S-video outputs at the back of the camera allow simultaneous viewing and recording. An aux port allows a remote keypad to be used for menu access without causing camera shake when pushing the rear buttons. The aux port can also be used for computer control with available software for image capture.

FRAME RATE Shutter speeds range from 4 seconds to 1/12,000th of a second. This making the Xtreme well suited for lunar and planetary filming, but deep-sky observing is where it excels. An optional wireless exposure controller is a must as it sets the Xtreme apart, allowing for longer exposures of up to 99 minutes.

skyatnightmagazine.com 2013

>

1. Wireless exposure keypad 2. Hand controller 3. MFR-5 focal reducer

> The rarified gas of the Dumbbell Nebula in Vulpecula showed up well

view, revealing more subtle colours. Something that was an indistinct smudge through an eyepiece of the 14-inch scope became instantly recognisable.

Going live The overall image quality doesn’t compare to that of astro CCD cameras with their larger sensors, but you have to remember this is a video camera optimised for live viewing with no processing or image stacking and, as such, it is impressive. With knowledge, the Mallincam Xtreme is straightforward to operate; a familiarity of video would come in handy for getting to know it. However, once you grasp the principles, getting to see barely discerned objects come to life with shape, structure and – best of all – colour becomes addictive. From ‘wowing’ friends by turning ‘faint fuzzies’ into the real thing, to broadcasting live views at star parties or even helping as an optical aid for those with poor eyesight, this is a great outreach tool for enhancing deep-sky observing. For some it might just replace the eyepiece permanently. S

VERDICT

> The colours of the Ring

Nebula in Lyra were easily differentiated

skyatnightmagazine.com 2013

BUILD AND DESIGN CONNECTIVITY EASE OF USE FEATURES IMAGING QUALITY OVERALL

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

WWW.THESECRETSTUDIO.NET, MARK PAYNE-GILL X 2

SKY SAYS… Now add these:

recorded after just 20 seconds. These could be enhanced with the auto white balance setting in the menu. Adjusting the Gamma setting from 0.45 to 1 darkened the background, increasing contrast nicely. Once displayed, the image remains while the sensor builds up the next exposure. If there is any movement in the imaging train between exposures it shows up on screen, adding to its live feel.

       
Our HI-LUX coating can be applied to almost any reflector, in virtually any condition or no matter how High Reflectivity old. Improves the reflective efficiency of your mirrors. Coating Find out more on our website: Optics > Mirror Recoating or call / email

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102

Books New astronomy and space titles reviewed

Unseen Cosmos The Universe in Radio

IANTCONFIG SKA SA

Francis Graham-Smith Open University Press £19.99 z HB Radio astronomy is a powerful tool in the modern astronomer’s arsenal. The discipline, although less than 80 years old, has led to significant advances in our understanding of the cosmos, from tests of Einstein’s theory of general relativity to or method, allowing the reader time to observational evidence for the Big Bang. comprehend its significance. The mapping Indeed, of the 10 astronomers who have of the Milky Way’s structure, cosmic rays, been awarded the Nobel Prize in Physics, radio spectral lines, the discovery of six of them employed radio telescopes for quasars, black-hole induced activity in the work that won them the accolade. radio galaxies, the serendipitous There can be no better discovery of pulsars and the advocate for the field than cosmic microwave Sir Francis Graham-Smith. background: all of A former Astronomer these are dealt with Royal and director of in a succinct and the Royal Observatory accessible way. For Greenwich, Grahamamateur science Smith is a veteran of enthusiasts there radio astronomy, can be no better beginning his career introduction than this. in the field’s infancy Graham-Smith rounds and playing no small off with a summary of part in its development. current and planned radio Unseen Cosmos is therefore scopes. The Square Kilometre written with a conviction and The SKA will be comprised of around Array (SKA), a mammoth soon personal involvement not 3,000 dishes to be built in Australia and found elsewhere. Africa will have a sensitivity 50 times what This is a history of radio astronomy, is currently available. Needless to say, we can but the text does not linger on the look forward to the discoveries this (and historical development or languish in other) instruments will make with relish. overly detailed narrative. The reader is taken quickly through a journey that ★★★★★ began with Grote Reber’s first detection of cosmic radio noise in 1937 through to ALASTAIR GUNN is a radio astronomer Jansky’s seminal work and the expansion at Jodrell Bank Observatory in Cheshire. of the technique in the post-war era. At each major discovery, the author takes Reader price 16.99, subscriber price 15.99 time out to consider the basic science, P&P £1.99 Code: S1213/1 skyatnightmagazine.com 2013

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

TWO MINUTES WITH FRANCIS GRAHAM-SMITH What inspired you to write this book? I have been a radio astronomer since the early discoveries in 1946. I wanted to share the excitement and joy of discovery in this new window on the Universe. What have radio telescopes taught us that we didn’t know before? The new window has revealed new objects and new physics, and given us the first evidence of the origin and development of the Universe. There have been discoveries like superdense matter in neutron stars as pulsars and superstrong magnetic fields in these pulsars. We’ve found superweak magnetic fields between the stars, traced the structure of galaxies from radio hydrogen spectral lines and identified quasars – the most energetic and most distant objects in the Universe. Radio telescopes have imaged the cosmic microwave background and identified organic molecules from their radio spectral lines. We’ve even been able to prove Einstein’s theory of general relativity through pulsar timing. What do you think the future holds for radio astronomy? A number of new telescopes using new techniques are coming into use across the globe and in space. The largest is the Square Kilometre Array, a huge international project that will improve our capabilities by orders of magnitude. It will address all branches of astronomy, including the understanding of the origins of life. FRANCIS GRAHAM-SMITH was Astronomer Royal from 1982 to 1990

BOOKS DECEMBER 103

Comets!

BOOK OF

including the dramatic break-up THE of Comet Shoemaker-Levy 9 and MONTH its subsequent battering of Jupiter in 1994. History’s great comets are also covered, including the relatively recent beauties Hyakutake, Hale-Bopp and McNaught, as is the science from David J Eicher close-up studies by robotic spacecraft and Cambridge University Press the effects comets have had on the growth £19.99 z PB of the Solar System – and perhaps even the spread of life. We also learn how these Author David J Eicher unexpected ‘hairy stars’ have influenced admits that this is the human culture. quickest book he has ever While recognising that C/2012 S1 ISON written, clearly keen to reach readers as excitement could become a great comet, Eicher sensibly avoids making any firm guide to builds around Comet its behaviour. There is, however, a section C/2012 S1 ISON. But it on how to observe and even search for seems in no way rushed. comets, plus advice on imaging them. In We are in the safe hands of an all, this is a lovely guide to comets that will experienced astronomer and journalist remain valuable long after this particular whose own interest in stargazing was icy visitor has departed our skies. piqued by the splendid pre-dawn sight of Comet West from a corn field in 1976. For ★★★★★ Eicher this was a life-changing moment – as he says, comets “trigger something PAUL SUTHERLAND is a regular contributor deep within the soul”. to BBC Sky at Night Magazine His highly readable account describes what comets are, where they come from Reader price 17.99, subscriber price 16.99 P&P £1.99 Code: S1213/2 and how they perform, with examples

Visitors from Deep Space

Planisphere and Starfinder Carole Stott and Giles Sparrow DK £14.99 z HB In a market awash with inexpensive planetarium apps for smartphones, the idea of holding a traditional planisphere above your head as an aid to identifying the stars may seem quaintly anachronistic. But in this case, even the iTunes generation should take notice. Jointly authored by Carole Stott and Giles Sparrow, Planisphere and Starfinder is a profusely illustrated 128-page hardback targeted at beginners that comes with a 28cm-diameter planisphere. In four concise yet comprehensive sections the book introduces you to night-sky nomenclature, the Solar System, the constellations and a detailed monthly sky guide through to 2019. While the planisphere is configured for

a latitude of 55° north, the constellation section covers the whole sky in order of decreasing declination from the north celestial pole. The planisphere shows a wealth of clear detail, including prominent deep-sky objects, but when we took it our for a test run we found the text on the moveable date and time dial was faint and barely legible, especially under red light. A guide to scale in everyday terms of reference, like the span of a fist or hand at arm’s length projected onto the sky, would be a useful aid for those new to astronomy, particularly in reference to star hopping and the constellations, and there are minor errors: the photograph of the Keystone asterism in Hercules is upside down (page 109), plus there are actually three main types of telescope design, not two (page 31). But in an otherwise well conceived and produced beginner’s guide that offers good value for money, these are relatively minor detractions.

★★★++

ADE ASHFORD is an astronomy writer

Planetary Climates Andrew P Ingersoll Princeton University Press £19.95 z PB Prof Andrew Ingersoll has made many important contributions to planetary science through his career, and in Planetary Climates he wields his immense expertise to really get across the weirdness of weather systems on other worlds. Why is it that as you move out through the planets of the Solar System wind speeds actually increase rather than grow calmer? Or that on Earth, the weather is dominated by the water cycle, but Mars has two kinds of cloud – water and carbon dioxide – while the atmosphere of Jupiter has three distinct cloud layers: water, ammonia, plus a compound of ammonia and hydrogen sulphide, stacked atop each other? The author explains all, as well as why the rainiest regions of Saturn’s moon Titan, where we find the hydrocarbon lakes, are towards the poles rather than around the tropics as on Earth. Ingersoll delves into detailed explanations of such fascinating alien weather and offers mathematical definitions in separate sections that don’t break the flow of the narrative. This makes Planetary Climates a perfect undergraduate primer as well as a book for interested amateurs. Although the writing is a little dry, Ingersoll’s passion for the subject carries you along and the text is studded with intriguing revelations. My favourite: that the deep internal heat source in Saturn is the precipitation of helium raindrops, just like how the condensation of water vapour powers hurricanes on Earth.

+++++

LEWIS DARTNELL is an astrobiologist at the University of Leicester Reader price 13.99, subscriber price 12.99 P&P £1.99 Code: S1213/3

Reader price 11.99, subscriber price 10.99 P&P £1.99 Code: S1213/4

skyatnightmagazine.com 2013

104 GEAR DECEMBER

Gear

Vincent Whiteman rounds up the latest astronomical accessories

1 1 Mars Jigsaw Puzzle Price £14.99 s Supplier Jigsaw Puzzles Direct 01287 659036 s www.jigsawpuzzlesdirect.co.uk Explore the surface of the Red Planet with this 1,000-piece puzzle. Discover Mars’s features, explore its internal structure and learn more about its two moons, Phobos and Deimos.

2 Polarscope Illuminator Price £46.20 s Supplier 365 Astronomy 020 3384 5187 sWWWASTRONOMYCOM Having trouble aligning in the dark? This illuminator fits into the front opening of your mount’s declination axis to provide a red glow, gently lighting up your polarscope’s reticule.

3 Celestron Homecast Deluxe Weather Station Price £85 s Supplier Rother Valley Optics sWWWROTHERVALLEYOPTICSCOUK Celestron’s weather station provides real-time local information on its five-icon display to help you plan your observing sessions. Sun and Moon rise and set times are also displayed, as are Moon phases.

4 Ostara 1.25-inch Luminance Filter Price £24.99 s Supplier Northern Optics 01724 782022 s www.northernoptics.co.uk Tackle oversensitivity to ultraviolet and infrared light in your CCD camera with this luminance filter – specifically designed for CCDs to help you reduce oversaturation.

5 Helix Nebula iPhone 5 Cover

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Price £26.78 s Supplier Redbubble sWWWREDBUBBLECOM Shroud your smartphone in stars with this iPhone 5 cover showing off one of Hubble’s awe-inspiring images of the Helix Nebula. Covers for older models are available too.

6 Hyperion Eyepiece Starter Set Price £400 s Supplier David Hinds www.baader-planetarium.uk.com Supplied in a padded hard case, the four eyepieces in this set (5mm, 10mm, 17mm and 24mm) are all multicoated for optimum image contrast and light transmission.

6

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106 EXPERT INTERVIEW DECEMBER

WHAT I REALLY WANT TO KNOW IS…

How can we look for life on exoplanets? John Lee Grenfell is preparing to work with powerful new telescopes to look for biosignatures in alien atmospheres INTERVIEWED BY PAUL SUTHERLAND

I

n recent years, hundreds of new planets have been discovered orbiting other stars. The vast majority of them are likely to be inhospitable but I want to know if we could detect signs of life on those planets that are in a position to support it. As bigger and more powerful telescopes become available, I believe we might be able to pick up ‘biosignatures’, signals that will tell us that life could be present. I’m not talking about deliberate alien messages, such as radio communications, but rather the types and abundances of gases in a planet’s atmosphere. For example, microbes give off methane and nitrous oxide, so high abundances of those gases might indicate life on an exoplanet. With next-generation telescopes, we think it will be possible to detect such signals from close-by terrestrial planets, providing conditions are right. But the signals will be very weak and so to be able to measure them, the telescopes will need to be very powerful.

Is anything out there? Clues to the presence of life may be found by examining exoplanet atmospheres

THINKSTOCK

Laying the foundations We will need to wait for instruments such as the European Extremely Large Telescope (E-ELT) and NASA’s James Webb Space Telescope (JWST) to come online before we can start searching for these biosignatures. The JWST won’t launch until 2018, at the earliest, and the E-ELT won’t be built until a few more years after that. In the meantime, we are busy carrying out computer modelling to discover what range of signals could be expected. One way of doing this is to imagine that Earth is our planet-of-interest and to consider how we might pick out the biosignatures if Earth were orbiting other stars. Although we base our studies on Earth – the only example we have of a planet with life – we have to keep an open mind and be prepared for surprises when examining signals in alien atmospheres. skyatnightmagazine.com 2013

ABOUT JOHN LEE GRENFELL

Dr John Lee Grenfell is a researcher investigating exoplanet atmospheres at the German Aerospace Centre’s Institute of Planetary Research in Berlin.

We will want to study exoplanets that orbit their host star in the habitable zone, the orbital region where water could exist as a liquid on a planet’s surface. And we will need to study planets that transit across the face of those stars to gain information on their chemistry. We have therefore been simulating abundances of different biomarkers under different conditions (for example varying the planet-star distance or the type of star) to model the signals that arise when light shines through a planet’s atmosphere and travels to Earth. The stars we will focus on in our search for planetary biosignatures are likely to be the cooler ones, such as red dwarfs, because they will make our hunt easier. They are less bright and smaller, so the planetary signal is relatively stronger. Also, because the habitable zone around a cooler star must be closer to it, our target planets would orbit much more quickly. They’d orbit in days rather than years, which means we would be able to observe more transits over a given period. One thing we’ve learned is that there seems to be a ‘Goldilocks’ effect with respect to the biosignature of ozone. If the ultraviolet radiation from a host star is weak, less ozone is produced in the planet’s atmosphere, making its detection challenging. But too much ultraviolet light leads to increased heating in the atmosphere, which destroys the signal. Somewhere between the two, the conditions for detecting ozone are ‘just right’. Some people ask why we’re starting work on this now when we’re not going to get any data for perhaps another 10 years. The reason is that we need a strong theoretical framework to get an idea of what the main challenges are, because the process so complicated. We need to know what is important to find out about stars and what isn’t. That way we can devise a process that allows us to predict of the type of signals we might eventually detect. Preparation is everything. S

SOUTHERN HEMISPHERE IN DECEMBER With Glenn Dawes

> 1 December 00:00 > 15 December 23:00 > 31 December 22:00

DECEMBER HIGHLIGHTS

STARS AND CONSTELLATIONS

Venus is impressive in the western evening sky. In the first week of December it is visible 7° to the upper right of the handle of the Teapot asterism in Sagittarius. As Venus heads towards inferior conjunction – when it moves between Earth and the Sun – in January, its size and appearance will change. December opens with the planet 38 arcseconds across, with a shape similar to a four-day-old Moon. By Christmas it has grown to 55 arcseconds with the phase shrinking to just a sliver.

Here’s some trivia for your next star party: mag. +2.0 Hamal (Alpha (_ Arietis), mag. +2.2 Algieba (Gamma1 (a) Leonis) and mag. +1.2 Pollux (Beta (` Geminorum) are all due north this month. They are three of the brightest stars known to have at least one exoplanet – the first two in their habitable zones. Other naked-eye stars that have exoplanets and are visible this month include mag. +3.5 Epsilon (¡) Tauri, mag. +3.7 Epsilon (¡) Eridani and mag. +4.1 Upsilon (¯) Andromedae.

H E AS T

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

RT O N

WHEN TO USE THIS CHART

THE PLANETS Uranus are best caught in the evening, setting around 23:00 EST and 01:00 EST mid-month. Mars is now well placed in the pre-dawn, arriving around 01:00 EST. Saturn climbs out of the eastern dawn sky and at month end rises around 02:00 EST.

EAST

December opens with Venus low in the west after the end of twilight, but it is bathed in the Sun’s glare by month end. Jupiter, near to mag. +1.9 star Castor (Alpha (_ Geminorum), is at opposition in January and visible most of the night. Neptune and

DEEP-SKY OBJECTS The southern constellation of Sculptor is a dream for galaxy observers. Edge-on spiral galaxy NGC 134 (RA 0hr 30.3m, dec. –33° 15’), pictured, just 0.6° east-southeast of mag. +4.9 star Eta (d Sculptoris, is a great example. The galaxy appears as a mag. +10.3 haze measuring 5 arcminutes by 1 arcminute, with quite a bright, extended central region.

Look 1.8° south-southeast of NGC 134 and you’ll find the double star HIP 2663 (RA 0hr 33.7m, dec. –35° 00’). Its mag. +6.6 and mag. +8.5 yellow stars are separated by 5 arcseconds. Kappa1 (g) Sculptoris (RA 0hr 09.3, dec. –27° 59’), a close double with mag. +6.1 and mag. +6.2 components, is tougher: you’ll need a 6-inch scope and 200x magnification to split this one.

H UT O

GALAXY

ASTEROID TRACK

DOUBLE STAR

METEOR RADIANT

VARIABLE STAR

QUASAR

MAG. +3

COMET TRACK

PLANET

MAG. +4 & FAINTER

OPEN CLUSTER GLOBULAR CLUSTER

ESO

PLANETARY NEBULA

skyatnightmagazine.com 2013

STAR BRIGHTNESS:

DIFFUSE NEBULOSITY

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

S EA

CHART KEY

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SOUTHERN HEMISPHERE NORTH SOUTH