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Popular Astronomy 3www.popastro.comJanuary - February 2017

4 Editorial Amanda Doyle4 AstroNews Amy Tyndall

Supermassive black hole observed in galactic debris Andrew May Riddle of Moon's mysterious ringed crater solved Nicholas House Quasar halos could change theory of galaxy formation Thomas Barratt Imaging the birthplace of planets Emma Foxell New space strategies for “New Space” Matjaz Vidmar 9 Q&A with Chris Lintott 10 Telescope Topics Ian Morison Astronomy books, software and websites that will help you enjoy the night sky. 12 Amateur Scene Peter Wade Irish society selection / ASH members put to the test

Points mean prizes / On the trail of D. E. Benson A society in numbers / Out and about 17 Citizen Science Alice Sheppard Science, art and space junk 22 Young Stargazers Robin Scagell Hop on an asteroid Alan Ackerley From the Chief Stargazer Lucie Green Space hazards! Alice Sheppard Rocket race game Alice Sheppard

31 Space Exploration Helen Walker ExoMars Trace Gas Orbiter and Schiaparelli lander /

Launchers and landings / Curiosity and Opportunity still going strong / Goodbye to Rosetta / The Moon and an asteroid impact

34 Book Reviews The Cosmic Web Amber Hornsby Searching for the Oldest Stars: Ancient Relics from the Early Universe Osnat Katz 35 Section Reports Deep sky Dave Finnigan Lunar - Planetary Alan Clitherow Aurora and NLC Sandra Brantingham Variable stars Tracie Heywood Meteor Tracie Heywood 42 The Society Pages The SPA at Jodrell Bank SPA meetings Einstein’s Relativity: tested to the limit with pulsars Jack Meadows (1934–2016) 44 Sky Diary Moon data Mandy Bailey Lunar occultations / Planets Mell Jeffery / Alan Clitherow Meteor notes / Variable Star notes Tracie Heywood 46 SPA contacts47 Showcase

Features

EditorAmanda [email protected] TeamAmy Tyndall, Jo Barstow, Dwane DoyleMagazine LayoutMandy BaileyAdvertising ManagerMargaret PenstonDistribution ManagerBarry Turvey36 FairwayKeyworthNottinghamNG12 [email protected] and distributorsAdlard PrintThe Old School, RuddingtonNottingham NG11 6HH

Popular Astronomy welcomes articleson all aspects of astronomy. Opinionsexpressed in Popular Astronomy arenot necessarily those of the SPA. TheSPA can’t be held responsible for theaccuracy of descriptive statements orfor the quality of goods advertised. ISSN: 0261-0892© 2016 The Society for Popular Astronomy.

Regulars

14 The jewels of Perseus Martin Griffiths

18 The origins of popular astronomy Allan Chapman

26 A day in the life of a radio astronomer Megan Argo

28 Is Proxima b habitable? Amber Hornsby

Cover:Artist’s impression of

the surface of the planetProxima b orbiting thered dwarf star Proxima

Centauri. The doublestar Alpha Centauri AB

is also shown.Credit: ESO/

M. Kornmesser

Production

Popular AstronomyVolume 64, Number 1 January–February 2017

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EDITORIAL

www.popastro.com4 Popular Astronomy January - February 2017

Astronomers have used a global network of ten radio telescopes toobserve a supermassive black hole speeding away from the aftermath of

a galactic collision.As galaxies such as our own hurtle through the Universe at hundreds of

thousands of kilometres an hour, collisions are inevitable. Whilst our MilkyWay is not due to cross paths with the Andromeda galaxy for another 4billion years or so, two galaxies within the cluster ZwCl 8193 have not beenso lucky. Observations using the Very Long Baseline Array (VLBA) haverevealed the fascinating debris of this cosmic collision, located two billionlight years away – an object known as B3 1715+425

As the smaller galaxy of the two smashed through its neighbour, nearly allof the stars and gas were torn away, allowing only the core to survive andescape at a speed of around 3200 kilometres per second. In most galaxies, asupermassive black hole resides at the very centre and this is what has beenobserved in B3 1715+425 – the remaining supermassive black hole,surrounded by a very small amount of stellar material. In such smallquantities, this material will no longer be undergoing active star formation,meaning that the galactic remnants will eventually become unobservable.This raises the tantalising possibility that many of these objects exist in theUniverse but are simply too faint to detect.

These observations were carried out as part of wider survey dedicated tosearching for supermassive black holes not found in the centres of galaxies,which may be millions or even billions of times the mass of our Sun. “Wewere looking for orbiting pairs of supermassive black holes, with one offsetfrom the centre of a galaxy, as tell-tale evidence of a previous galaxymerger,” said James Condon, of the National Radio Astronomy Observatory.“Instead, we found this black hole fleeing from the larger galaxy and leavinga trail of debris behind it.”

It has been possible to acquire such exquisitely precise images because theVLBA is an interferometer: an array of telescopes that combine their signalsto synthesise a much larger dish, in this case consisting of ten 25m disheslocated from the Caribbean to Hawaii.

The results, which are soon to be published in Astrophysical Journal, werecompiled by Jim Corden at the National Radio Astronomy Observatory,along with Jeremy Darling (University of Colorado), Yuri Kovalev (AstroSpace Center, Lebedev Physical Institute in Moscow), and Leonid Petrov(Astrogeo Center in Falls Church, Virginia).

Andrew May is a PhD student in the Jodrell Bank Centre for Astrophysicsat The University of Manchester, where his work is presently concerned

with the development of instrumentationfor several forthcomingexperiments to study the cosmic microwave background.

ASTRONEWS

Calling all YoungStargazers! Would you like

to play a board game to race tothe nearest habitable planet? Ifso, turn to page 24 to playRocket Race and see page 23 forfurther details on your spaceadventure.

In reality, it will be a longtime before we can travel tohabitable planets beyond ourSolar System. But the search forsuch a planet is well and trulyunderway, and the discovery ofa potentially habitable planetaround our nearest star is quiteexciting. The planet – known asProxima Centauri b – wasdiscovered as part of the “PaleRed Dot” programme, which issearching for planets aroundnearby red dwarf stars. On page28 Amber Hornsby writes aboutthe newly discovered planet anddiscusses its potential as ahabitable planet.

A different red planet that ismuch closer to home – Mars – isproving that space explorationwithin our own Solar System isstill a precarious endeavour.Mars has claimed yet anotherrobotic victim with ESA'sSchiaparelli lander, whichcrashed into the surface on 19October. Unlike the ill-fatedBeagle 2 lander which crashedon Mars in 2003 and remainedlost until recently, theSchiaparelli crash site hasalready been imaged from orbitby NASA's Mars ReconnaissanceOrbiter. However, there is stillsome good news to this story, asthe orbiter that releasedSchiaparelli – the Trace GasOrbiter – is now in orbit aroundMars and is sending back data.You can read more about whatthe Trace Gas Orbiter will bedoing at Mars on page 31.

Amanda Doyle, Editor

Supermassive black holeobserved in galactic debris

▼ Artist's conception of how the “nearly naked” supermassive black hole originated.Credit: Bill Saxton, NRAO/AUI/NSF.



ASTRONEWSAMY TYNDALL presents the latest in

astronomical research and observations

New research into the Orientale Basin, a huge andenigmatic ringed structure on the lunar surface,

has revealed a much more complex and violent historythan initially expected. Utilising gravitational datacollected by a pair of NASA spacecraft as part of theGravity Recovery and Interior Laboratory (GRAIL)mission, a research team at Brown University, RhodeIsland, were able to reconstruct the basin and accuratelymodel its formation.

Positioned to the south west of the Moon's Earth-facingside, the Orientale Basin was formed some 3.8 billionyears ago and, at its maximum, has a diameter of over930 kilometres. Although it is agreed that the basin waslikely formed by a large impactor rather than internalprocesses, until now it has been debated exactly whattook place to form the feature's distinctive rings,especially in the subsurface. “In the past, our view ofOrientale Basin was largely related to its surfacefeatures,” remarked Jim Head, a Brown Universitygeologist, “but we didn't know what the subsurfacestructure looked like in detail. It’s like trying tounderstand how the human body works by just lookingat the surface.”

The importance of understanding exactly howstructures such as the Orientale Basin formed lies in thefact that they are unchanging records of planetarydevelopment, preserved from the early Solar System.Understanding the formation of these structures notonly helps us to decipher the early development of theMoon, but also many other planetary bodies thatexperience similar events. These bodies include Mars,Mercury and even Earth, where eons of tectonicprocesses have erased its own early features that couldhave helped us to understand crustal development.Head sums this up well as he explains “The Moon insome ways is a laboratory full of well-preserved featuresthat we can analyse in great detail.”

Typically, smaller impacts cause a depressed craterwhere material is expelled from the planetary body andthe impactor is completely obliterated. However, withevents such as the one that formed Orientale, where it isestimated that an almost 65 kilometre wide objectimpacted the Moon at upwards of 14 kilometres persecond, the result can be much different. Data fromGRAIL generated a model confirming that the sheerforce of this large collision caused what is known as a

transient crater between 320 and 480 kilometres indiameter and expelled over 1.3 million cubic kilometresof material. The impact would have caused the crust toheat, becoming very malleable and acting almost like afluid. As with a raindrop hitting water, the crust wouldhave flowed in towards the impact site, erasing theinitial transient crater and then rebounded outwardscausing the distinctive ripple-like features. Unlike atraditional fluid where the ripples dissipate, the ripplespropagating through the crust are frozen almostimmediately after impact. The resulting feature iscomposed of several concentric rings consisting of cliffsthat can reach several kilometres above the lunarsurface and a large and unstable central peak thatwould have eventually slumped outwards to form theinnermost ring.

This is the first time such a model has been developedto reproduce the formation of these ring basins and withseveral having been identified on the surface of Mars,this research gives a tantalising insight into whatknowledge is still to be gained from the GRAIL missionand into common processes of planetary developmentacross the entire Solar System.

Nicholas House is a Geology graduate with a passionfor writing and a keen interest astronomy. He currently

lives and works in Oxfordshire as a Systems Developer for the NHS.

Riddle of Moon's

mysterious ringed

crater solved

▲ The Orientale Crater. Credit: Ernest Wright, NASA/GSFCScientific Visualisation Studio.


ASTRONEWS

6 Popular Astronomy www.popastro.com January - February 2017

New observations of a sample of19 Quasi-Stellar Objects, or

“quasars”, using ESO’s Very LargeTelescope (VLT), have revealedgiant gaseous halos around each,which could require astronomers torethink how galaxies formed in thevery early Universe.

Quasars are some of the brightestand most distant objects in theUniverse. These phenomena, whichbear a visual similarity to stars intelescope images yet can shine 100times brighter than our entire MilkyWay, are the active cores of distantgalaxies. The light from a quasar isgenerated when the centralsupermassive black hole, thought tosit at the heart of most galaxies,consumes stellar material from anearby galaxy with which it iscolliding. As the material falls ontothe accretion disc of thesupermassive black hole, it releasesan incredible amount of radiationalmost uniformly across the

electromagnetic spectrum.It is this immense energy output

from the central quasar thatilluminates the gaseous halosurrounding them, causing them toglow and become visible toastronomers – something that hasbeen observed in around just 10% ofobserved quasars in previousstudies. The detection of such cloudsaround each of the 19 quasars inthis new study means thatastronomers may have to rethinksome of what they thought theyknew about how galaxies formednear the beginning of the Universe;as this new sample is so distant, weare in fact seeing how galaxiesinteracted and grew billions of yearsago.

A further surprise discovery wasthe temperature of the giant gasclouds. Analyses showed that thegas was around 10,000 degreesCelsius, which, in astronomicalterms, is quite cold. In fact, if the

current theories of galaxy formationwere correct, these gas clouds shouldbe much hotter, upwards of a milliondegrees.

“It is still too early to say if this isdue to our new observationaltechnique or if there is somethingpeculiar about the quasars in oursample,” said lead author of thestudy Elena Borisova of ETH Zurichin a statement. “So there is still a lotto learn; we are just at thebeginning of a new era ofdiscoveries.”

This research was presented in thepaper: “Ubiquitous giant Lyαnebulae around the brightestquasars at z ~ 3.5 revealed withMUSE”, to appear in theAstrophysical Journal.

Thomas Barratt is anastrophysics graduate and sciencewriter, currently working with the

outreach department at theEuropean Southern Observatory.

Quasar halos could changetheory of galaxy formation

▼ This mosaic shows 18 of the 19 quasars observed, each surrounded by a bright gaseous halo – the first time that halos have been detectedaround all quasars within a given sample. Credit:ESO/Borisova et al.



ASTRONEWS

Planet imaging instrument SPHERE revealsstartling new details about three protoplanetary

discs and how they are being shaped bygrowing planets.

Where do planets come from? Planets in our ownSolar System and the few thousand exoplanets we

have found orbiting other stars only show us the endproduct. Stars form when clouds of dust and gas collapseunder gravity, with leftover material quickly flatteninginto a protoplanetary disc, like dough being spun into apizza base. Dust in the disc then sticks together andeventually builds up into planets through collisions.However we do not fully understand how the disc andplanets interact to affect the growing planets.

To investigate this, three teams of astronomers usedthe high resolution instrument SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) on theVery Large Telescope at ESO's Paranal Observatory inChile to directly image the structural detail of discsaround three stars. By picking stars with “transition”discs – i.e. discs that are in between the youngest andmore evolved discs – the young star has had time toblow away gas and dust close to it, so planets should beforming and their effect in shaping the protoplanetarydisc is most likely to be seen. Jos de Boer from LeidenObservatory observed young star FX J1615 anddiscovered a series of rings and gaps around it, likethose of Saturn but extending hundreds of AU (one AUis the distance from the Sun to the Earth). They alsofound suggestions of growing planets potentially causingthe gaps between rings. FX 1615 is also interesting as itis only 1.8 million years old (compared to our Sun's 4.6billion years) and is much younger than most othersystems, so we can see the first stages of planetformation.

How does SPHERE image the faint discs surroundingthe much brighter stars? Using a coronograph, likethose used to study the outer layers of the Sun,SPHERE can block most of the light from the star.SPHERE's polarimeter then filters the light to extractonly the polarised light (where the light waves oscillatein a plane) reflected from the planetary surface and

discard the unpolarised light (where the waves oscillatein different directions) directly from the star, in asimilar way to polarised sunglasses.

Another interesting example was announced soon afterby Christian Ginski, also from Leiden Observatory. Theprotoplanetary disc of HD 97048 was well known, butthe team used SPHERE to view it in unprecedenteddetail. They discovered HD 97048 also has the moreunusual symmetric ring structure with four huge ringsbetween 39 and 341 AU. They calculate that the gapscould be caused by protoplanets smaller than Jupiter.

HD135344B is particularly interesting as itsprotoplanetary disc has a large hole in the middle withno dust, suggesting it is in the last stages of transitiondisc evolution. Tomas Stolker of the Anton PannekoekInstitute for Astronomy suggests that the disc's twospiral arms may be shaped by two planets forming inthe outer disc. Amazingly, whilst SPHERE could notobserve the inner part of the disc, it could see theshadows of four objects close to the star. One shadowchanged between their observations, showing we candetect planet formation in real time!

Observations of transition discs are building on ourunderstanding of how and when giant planets form andhow the discs influence the growing planets. Futureobservations of disc chemistry and gas to dust ratio indiscs will help us place our Solar System in context.

Emma Foxell is a PhD student at the University ofWarwick searching for new exoplanets around

bright stars using ground based telescopes.

Imagingthe birthplace

of planets

▼ The planetary disc around HD 135344B as seen by theSPHERE instrument. Credit: ESO, T. Stolker et al.

▼ Unpolarised light from a star has waves that oscillate in differentdirections. When this light is reflected from a planet or a disc the lightbecomes polarised, meaning that it is now only oscillating in a singleplane. The polarimeter on the SPHERE instrument can differentiatebetween the two types of light, making it easier to spot planets andprotoplanetary discs. Credit: ESO.


ASTRONEWS


Two new reports published inOctober 2016 indicate that the

concept of “New Space” – that is,how the UK Space Sector isdeveloping – has well and trulylanded.

“New Space” is the label attachedto the radical shift in the SpaceSector make-up, which is looking toexploit advances in technologydevelopment and new sources offunding. The aim is to push forwardrapid design, manufacturing anddeployment of small, cheap anddispensable (or even replaceable)satellites for an increasing variety ofapplications, whilst making itaccessible to a growing number ofusers worldwide.

On 27 October, the Organisationfor Economic Cooperation andDevelopment (OECD) published itsSpace and Innovation report,analysing in great detail the currenttrends in the Space Sector and thevariety of policy responses countrieshave been adopting. It suggeststhree approaches for both state andprivate sectors: reviewing policy inlight of new developments, direct

involvement in new (downstream)space activities, and capturing spin-offs and technology developments.The report optimistically predictsthat “the space sector seems to be onthe verge of a new cycle ofdevelopment”, with new scientificbreakthroughs, technologicalachievements and a growing marketfor space applications – and all verybeneficial to the global economy.

The key contribution of the SpaceSector to the economy is alsorecognised in the EuropeanCommission’s Space Strategy forEurope, published on 26 October. Itsets out ways in which the EU seeksto boost growth in the sector andhow knowledge spill overs in otherdomains, through flagshipprogrammes such as Galileo(satellite navigation) and Copernicus(satellite imaging), science andinfrastructure investment, andfinancial support for start-ups andspin-offs based on space-relatedtechnologies.

Elżbieta Bieńkowska,Commissioner for Internal Market,Industry, Entrepreneurship and

SMEs, noted that although “Space isa key industrial sector in Europe'seconomy, and a strategic assetsupporting Europe's autonomy ofaction at the global stage [...], itneeds more entrepreneurs and moreprivate investment if it is to stayahead of the curve.” This can only beachieved through public and privatesectors working together and pullingthe (financial) weight.

Of course, these are long-termstrategies and it is unclear in whatway the UK Government will pursuethem, though UK leadership in thisarea has been very strong in thepast. In fact, UK National SpacePolicy, last updated in December2015, is very much at the heart ofthe current OECD and EU thinking;however, the changing globalcontext, in particular the role of theUK in European affairs, may welljeopardise our hard-earned positionof global leadership in the SpaceIndustry.

We may have to wait until nextyear’s UK Space Conference, thistime in Manchester, to measure thestrength of the new Government’scommitment to the sector and globalpartners’ reaction to our changingposition in the world.

Matjaz Vidmar is a PhD studentbased at The University of

Edinburgh / Royal ObservatoryEdinburgh, researching Innovation

in the Space Sector. For moreinformation about his work see:

www.roe.ac.uk/~vidmar.

Links for further information:

UK Government, National SpacePolicy:www.gov.uk/government/publications/national-space-policy

UK Space Conference 2017:ukspace2017.co.uk/

▲ Credit: ESA-P. Carril

New space strategies for“New Space”


When you started theGalaxy Zoo and theZooniverse, were youexpecting it to be sosuccessful?

No. We had no idea what we weredoing. It was supposed to be a nicequiet side project. I'd grown up as anamateur astronomer so the idea wasthat we'd create Galaxy Zoo and maybeI'd talk to an astronomy society andmaybe 50 people would do 50classifications each. We estimated in2007 that by 2012 we might have gonethrough a million galaxies once each –we did that in the first three hours. Soit's completely unexpected and Iremember sitting there wonderingwhat on Earth we'd done. Mainly Ithink that was a lack of optimism.What I'd missed was that even peoplewho aren't already interested inastronomy wanted to make acontribution to science and the ideathat they could do something usefulwas very exciting. So once you'verealised that people are generally goodand happy to help then perhaps it's notso unexpected.

How important is citizenscience to professionalresearch and how muchof it have you used?

We won't launch projects that don't getused so we test our projects to makesure that they're useful. There havebeen more than 120 papers publishedusing the results of Zooniverseprojects, most of them in astronomywhich is excellent. But I think the realimportance is that it allows us to payattention to the weird and the unusual.We got quite good as astronomers atdealing with big surveys and bigdatasets and studying normal galaxies,normal stars, normal planets – butthere's an old fashioned version ofastronomy that's still very usefulwhich is to find the unusual object anduse that to tell you about the Universe.With citizen science we can payattention to every image and everyobject. Then we have volunteers whoare good at highlighting those things,as well as just sorting through the bulkof data; finding the serendipitous hasbeen really good. Things like Hanny's

Voorwerp – which is a gas cloudenergised by a black hole – or therecent “WTF star” which is the starwith a ridiculous series of transitswhich make no sense whatsoever, butwhich some people think might be analien “megastructure”. Whatever thatis – I'm not convinced! Butnevertheless it's a sign of how unusualthe thing is that people are reaching tothose explanations. And no one wouldhave paid any attention to thatwithout volunteers looking at it.

What does your ownresearch involve? Areyou just using the datafrom Galaxy Zoo?

My own research uses data fromGalaxy Zoo and I'm particularlyinterested in what astronomers havestarted to call secular evolution, whichis a terrible name for what happens togalaxies when they haven't had amerger. When I was growing up andmaybe even as recently as 5-10 yearsago, the textbook story was that therewere mergers between galaxies – thesebeautiful fireworks displays – andthat's what influenced the future of thegalaxy. Actually most of the stars arenot born in big major mergers andcertainly in the local Universe it's notthose mergers that are determiningthe galaxies that we get. We're tryingto look at how more subtle processeswork. For example, there's a set ofgalaxies in Galaxy Zoo which are discgalaxies but which have no bulge atthe centre. So if you think of the MilkyWay as two fried eggs, there's no yokehere. And that's exciting because thesegalaxies are basically guaranteedmerger free. If you had any sort of bigmerger you would have ended up witha bulge. These are a test case for whatcan happen to a galaxy. So we've beenstudying those and we've got sometime on the Hubble Space Telescope tofollow up on a sample of these thingswhich is really exciting.

What was it like to gofrom watching the Sky atNight to presenting it?

It seems like it happened gradually. Igrew up watching it – actually I grewup watching videos of the Sky at Night

in our school astronomy club. We'dcome in the next day and watch it atlunch time. And then to find myselfpresenting has been an enormousprivilege. I think it's a very unusualshow in that we try and present what'shappening in astronomy as simply aspossible without losing track of the factthat we're reporting on the cuttingedge stuff – the real debate that'sgoing on. So I think having watched itI have quite a good sense of what thatis. I'm not really answering yourquestions because it's very hard todescribe. I still find it surreal thatanyone out there is watching. Youknow I actually feel like I'm stillwatching it, it's just that I get to askquestions, I get to talk to thesewonderful people, and I get to be inamazing places.

Do you still get muchtime for amateurastronomy?

I do the world's least serious amateurastronomy. I have a 6” reflector whichhas no drive, and I've never used it forastroimaging and I'm not going to. Therest of my life is staring at the laptopscreen but when it's clear I'll beoutside normally looking at the OrionNebula if it's winter or just scanningaimlessly along the Milky Way in thesummer. So I do very casual amateurastronomer. It's a nice reminder of whyall of this is interesting – the fact thatit's also beautiful.

Q&A WITH CHRIS LINTOTT


Professor Chris Lintott, talks to Amanda Doyle aboutstarting Galaxy Zoo, the contribution citizen science makes toresearch and presenting Sky at Night.

▲ Image courtesy Chris Lintott. Credit: Sky at Night magazine.

Q

Q

Q

Q

Q


TELESCOPE TOPICSIAN MORISON explains aspects of instruments and observing

Star AtlasesAclassic, large scale, atlas is Will Tirion’s

Sky Atlas 2000 (2nd Edition). This can beobtained second-hand for ~£64 (~£150 new).A smaller version, also by Tirion, is TheCambridge Star Atlas (4th Edition) that canbe obtained new for ~£25. However, there isno doubt that the best, by far, is the newInterstellarium Deep Sky Atlas by Stoyan andSchurig (CUP). This contains 113 chartsshowing stars down to +9.5 magnitudes withclusters, galaxies and nebulae shown incolour. The size and saturation of the font foreach object indicates what sized telescope (4,8 and 12-inch) could be used to observe themvisually. The cost is now ~£60.

A wonderful photographic star atlas, TheGreat Atlas of the Stars by Serge Brunier,includes star fields taken by Akira Fujii anduses transparent overlays to highlight objectswithin the field. This can be bought second-hand for ~£25 (new £131!) and I urge you to buy one. A small section is shown in Figure 1. A more modernphotographic star atlas is The Cambridge Photographic Atlas of the Stars by Axel Mellinger and Ronald Stoyanwhich is available new for ~£40. The star fields are wonderful but not so “artistic” as those taken by Akira Fujii.

Books relating to observing the night skyAwonderful, and low cost (~£10), beginner’s guide to what can be seen in the heavens has been written by Robin

Scagell, our SPA vice president. Titled Philip’s Night Sky Atlas, it includes star charts by Will Tirion alongwith photo-realistic versions of the same regions and four excellent (one for each quadrant) lunar charts. There aresections on each of the major constellations and the objects to be seen within them, and guides to observing theplanets. Also, no beginner should be without Turn Left at Orion by Guy Consolmagno (the Pope’s astronomer) whichdescribes one hundred objects to observe with binoculars or a small telescope. It can be purchased from £16 new.Two of its charts are shown in Figure 2.


Astronomy books, software and websites thatwill help you enjoy the night sky.

▲ The transparent overlay over the Leo Image in The Grand Atlas of theStars. Credit: Bordas.1

▼ Two of the M42 diagrams in Turn Left at Orion along with the author’s image. Credit: CUP/Ian Morison.2


The Messier Catalogue is covered by many books. A mostimpressive book, with wonderful large scale images, is Atlas of theMessier Objects by Ronald Stoyan (CUP). It is available used from~£33. A further excellent book also published by CUP is Deep SkyCompanions: The Messier Objects by Stephen James O’Meara. Hehas also written further books in this series: The Caldwell Objects,The Secret Deep, Hidden Treasures and Southern Gems. All arewell worth buying. A slim, but excellent book, worth tracking downis The Messier Album: An Observer’s Handbook by John H. Mallas(who produced the text and drawings using a 4-inch refractor) andEvered Kreimer (who took the photographs using a 12.5-inchreflector). This can be obtained second-hand from ~£22. It includesa biography of Messier and a copy of his original catalogue (inFrench!) and gives an excellent feel of what we can expect toobserve ourselves. A final excellent book is Messier’s Nebulae andStar Clusters by Kenneth Glyn Jones – £44 in paperback.

Lunar atlases and booksAclassic, hand drawn, lunar atlas is the Atlas of the Moon by Antonin Rükl. It is well worth seeking out a second-

hand copy. (New copies are VERY expensive!) A superb photographic atlas is the 21st Century Atlas of the Moonby Wood and Collins. This is ~£25 from Amazon but may be found for less. The large scale Times Atlas of the Moonis based on the Lunar Surveyor images and charted by the US Air Force. This is the highest resolution lunar chartavailable and can be bought second-hand for ~£64.

A classic book with excellent descriptions of lunar craters and features is The Moon by Wilkins and Moore. Itincludes very detailed maps drawn by Wilkins. This can sometimes be found second-hand but is now quite rare.

Astronomical softwareThe classic, free, planetarium program is Stellarium which has much to

commend it. It is available for Linux, Mac and Windows computers andincludes 600,000 stars. I actually prefer Sky Safari Plus which costs about £10but is only currently available for Mac computers and iOS and Android tabletsand phones. My Mac version is used to control my telescope mount through a“SkyFi” wi-fi link and automatically downloads ephemerides for comets somaking them easy to locate. There is a “Pro” version which includes 12 millionstars and 740,000 galaxies! To keep track on the Moon’s phases and surfacefeatures, an excellent free program is the Virtual Moon Atlas:sourceforge.net/projects/virtualmoon/. A comparison of its chart and theauthor’s image at the same lunar phase is shown in Figure 3.

A very useful program for imagers is the Field of View Calculator found atastronomy.tools/calculators/field_of_view/. This allows one to select a very widevariety of telescopes and cameras and shows the field of view that will be seenrelating to many astronomical objects. Figure 4 shows the field of view thatwould be achieved when using an 8-inch, f/4, Newtonian and an 8 MegapixelCCD camera when used to observe the Leo Cluster of galaxies.

WebsitesMy own Night Sky page www.jb.man.ac.uk/astronomy/nightsky/ is as probably as good as any and describes

what there is to see each month, with details of the planets and constellations that are best seen along with alist of “Highlights”. The Sky & Telescope page written by Alan MacRobert gives details on a weekly basis:www.skyandtelescope.com/observing/sky-at-a-glance/. The National Schools’ Observatory gives star charts for eachnight at www.schoolsobservatory.org.uk/astro/esm/nightsky.

An excellent website to follow events relating to the Sun, Aurora and comets is spaceweather.com/. A further Sky& Telescope page, www.skyandtelescope.com/online-gallery/planet-pictures/, posts images taken by readers of theplanets and is well worth following.


TELESCOPE TOPICS

▲ A comparison of the Virtual Moon Atlas chartand the author’s image of the first quarter Moon.Credit:Virtual Moon Atlas/Ian Morison.

3

▲ The screen display produced bythe Field of View Calculator whenthe Leo Triplet is chosen to beobserved with an 8-inch Newtonianand CCD camera. Credit:Astronomy Tools.

4


AMATEUR SCENEPETER WADE’S round up of local astronomical society news and events

The island of Ireland has awealth of astronomical

societies, several spanning theborder between the UK and theRepublic.

The Irish Astronomical Society(IAS, www.irishastrosoc.org) formedin 1937 and claims to be Ireland'slongest running astronomicalsociety. Based in Dublin, it producesa quarterly magazine Orbit as wellas an annual almanac Sky-High.Formal meetings are held at ElyHouse, though the society also hasan informal Dublin SidewalkAstronomers group which hasoperated since 1989.

North of the border, the IrishAstronomical Association (IAA,www.irishastro.org.uk) has amembership of over 200 drawn fromacross the UK and Ireland. Lecturemeetings are held at Queen'sUniversity in Belfast, alongside anobserving programme which pairsup experienced observers andbeginners.

Along with the IAS and the IrishFederation of Astronomical Societies(IFAS) , IAA members contributedpictures to a summer exhibition lastyear, Images of Starlight, inBelfast's Linen Hall Library. IAAmembers are also to be foundsupporting Ireland's annual cycle ofstar parties: Cosmos in Athlone,

Dunsink Observatory, Skellig inCounty Kerry and the Mayo DarkSky Festival.

Astronomy Ireland(www.astronomy.ie) is one of thecountry's newer societies.Forthcoming events include a NewYear lecture, participating at theYoung Scientist Exhibition, eveningclasses, public lectures, Jupiterwatches, Sun watches, the annualnational Perseid watch and theStar-B-Q at Roundwood in CountyWicklow, described as “Ireland'sbiggest star party”.

Galway Astronomy Club holdsobserving nights at the WestwoodHouse Hotel, Moon Fests on Salthillpromenade and back to basics

workshops. Their website(www.galwayastronomyclub.ie) hasa good beginners section with tipson finding your way around the sky,books, binoculars, equipment,YouTube resources and astronomyapps.

The Northern Ireland AmateurAstronomy Society (NIAAS) hasgrown from the East Antrim AS(hence its web address ofwww.eaas.co.uk) which originallyformed in 1997. Meetings are heldat Ballyclare High School and, aswell as lectures, activities includeobserving events, barbecues andpublic involvement events. TheNIAAS's magazine Azimuth isproduced every other month.


Irish society selection

ASH members put to the testMembers of the Astronomical Society of Haringey

(ASH) have been put through their astronomicalpaces with a quiz set by society Treasurer, KyriVaskou. One letter from each answer spells out thename of a well-known part of a winter/springconstellation.

For those who want to pit their wits against the ASHmembers, the clues were as follows: a University ofManchester TV astronomer; the second man to walkon the Moon; the Chinese lunar rover; an ex-planetbeyond Neptune; constellation containing X-1; a 111 mrocket; the creator of the Jodrell Bank radio telescope;the colour of the hottest stars; the star closest to the N

celestial pole; and Saturn's largest moon.The quiz looks set to become a regular feature of

ASH's newsletter, 2002. A follow-up AstronomicalQuestion Time gave clues to an object to be found atthe heart of our Galaxy. Again, the object was revealedwith one letter from each answer.

The clues were: the opposite of Australis; theEdmond whose name is given to our most famouscomet; a minor planet; the closest planet to the Sun;The Sky at Night's longest-serving presenter; the "BigEye" telescope at Mount Palomar; Mars' larger moon;Earth's radiation belts; and the constellationcontaining Castor and Pollux.

▲ Skellig star party 2016. Credit: Pete Williamson FRAS.


The speakers at forthcomingmeetings of Liverpool AS

are Melanie Davies with ThePleiades on 20 January and DrAllan Chapman on 24 February.The meetings start at 19:00 inthe Quaker Meeting House,School Lane, Liverpool.

Cardiff AS welcome MarcDelany with his

Introduction to PracticalAstronomy (5 January), Dr JanaHorak from the NationalMuseum of Wales on Meteoritesand Impactites (19 January),Phillip Wallace on Project Orion(2 February) and Prof HayleyGomez on Space dust (16February). Meetings are held inthe Physics and AstronomyDepartment of CardiffUniversity. For details visitwww.cardiff-astronomical-society.co.uk.

The Federation ofAstronomical Societies held

its 2016 Annual Convention atthe University of Birmingham inOctober.


AMATEUR SCENE

Out andabout

Write toAmateur Scene

If you would like your society’sactivities (past, present or future)

mentioned in these pages of Popular Astronomy, write to:Peter Wade: 24 Manor Grove,

Morecambe, LA3 1JAor email [email protected]

In the September-OctoberAmateur Scene I asked if

anyone could help GerardGilligan in his quest forinformation about D. E. Bensonand his pamphlet The Making ofa Speculum.

Tony Kinder, a past Director ofthe Historical Section of theBritish Astronomical Association(BAA), has been in touch withsome clues. First, we know thatBenson became a member of theBAA in 1894 and that his addresswas given as Queenwood,Lansdowne Road, Southport.Census returns reveal that hewas born in Manchester in 1860

and that his employment in 1901was described as both engineerand laundry proprietor. Thefollowing census in 1911 describeshim simply as a laundryproprietor. Benson died in 1937.

As to Benson's pamphlet, Tonyis certain no copy liesundiscovered in the BAA Library.However, he suggests a copy mayyet be found in the collection ofthe Royal Astronomical Society.

Gerard Gilligan has meanwhilebeen in touch with news ofBenson's photographic exploitsand his attempt to repeatedlyphotograph the Moon over thecourse of a month.

On the trail of D. E. Benson

Mexborough and Swinton AS(M&S AS) will give a warm

Yorkshire welcome in March to thelatest of the Back to Basicsworkshops arranged around thecountry by the British AstronomicalAssociation.

The society was formed in 1978and quickly grew, moving into itscurrent meeting place in SwintonWorking Men's Club in 1980.

M&S AS's activities aresummarised in numbers in thesociety's annual report: 46 members,55 meetings, 16 guest speakers, and45 community and access eventsreaching 983 members of the public.

Outreach events have been held inpartnership with the RSPB, Friendsof Clifton Park, and ThryberghCountry Park, with community

access events including viewingevenings and summer solar viewing.M&S AS has also supported largenational events such as NationalAstronomy Week, National Scienceand Engineering Week and theInternational Year of Astronomy.

M&S AS's JA Jones HooberObservatory opened in 1993 andstands on a site rented fromYorkshire Water. Fundraisingincluded a sponsored swim along thelength of Lake Windermere. Theswim on a freezing November dayraised a much needed £400 for theobservatory.

To find out more aboutMexborough and Swinton AS visittheir website at msas.org.uk whichhas full details of their programmeof meetings.

A society in numbers

Orwell Astronomical Society has been running aMember of the Year scheme in which members are

awarded points for helping run society events or inpromoting the society. Leading a workshop resulted inthe award of 20 points, helping at an outreach event 10points, introducing a new member 5 points and writinga newsletter article 3 points.

The Member of the Year scheme ran up to the end ofAugust with points translating into prizes, in this case ayear's free membership. The winner was Bill Bartonwith an amazing 196 points, well ahead of his nearestrivals Alan Smith and Mike Nicholls. The race isalready on for this year's prize!

Points mean prizes


The constellation of Perseus is instantly recognisableand can be seen from the UK for an appreciable

part of the year as much of the group is circumpolar.The constellation is representative of the eternal storyof triumph over adversity that features in many Greekplays of the classical period. Perseus was the son of Zeusby the princess Danae and was fated to go throughmany adventures, including the killing of Medusa theGorgon and Cetus the sea monster, to finally get the girlat the end of the story. All the characters in the Perseuslegend are with him in the sky as constellations in theirown right; Andromeda, Cassiopeia, Cepheus, Cetus andthe winged horse Pegasus.

Perseus is one of the truly great constellations as faras the observer is concerned. Lying along the MilkyWay, the astronomer is guaranteed a feast of objects todelight and inspire, and that is what Perseus has inabundance. His figure sweeps along the galactic plane;sword held high, feet firmly planted, it is easy to see thepattern of stars as none other than a heroic figure. Theprimary star of the constellation, Mirphak, is part of alarge cluster of relatively nearby stars that are a stellarassociation called the alpha (α) Persei moving group orMelotte 20, a wonderful sight in binoculars, as thecompanions are mostly bright B-type stars numberingover 40 in a scattered little field. Melotte 20 is between550 and 650 light years away so the stars making upthis group are very bright giants. Mirphak itself is an F-type yellow-white star and is classed under the

Morgan-Keenan-Kellman (MKK) system as class Ibmeaning that it is amongst the most luminoussupergiant stars in the sky.

Follow the upraised arm of Perseus along the MilkyWay to a misty spot of diffuse light midway betweenPerseus and Cassiopeia, and you will be rewarded withthe most exquisite star cluster in the whole heavens, ormore appropriately, two clusters. This is the famous“Sword Handle”; NGC 869 and NGC 884, commonlyknown as Caldwell 14 too. The clusters are burstingwith stars, containing over 1000 in two differentgroupings. Despite their extreme distance of 7,500 lightyears the two groups are easily visible in binoculars andsmall telescopes where the sight is awe-inspiring; astarfield dripping with stardust and chains andpatterns of all descriptions. There are more than 300blue supergiants in the clusters and together they havea mass close to 20,000 times that of the Sun, hinting ata massive halo of stars that just cannot be seen due tothe enormous distance.

The objects were first described by Hipparchus ofRhodes in 130 BC as a mist patch in the heavens thoughit was William Herschel who catalogued them as twoseparate entities. Words fail to describe this tiny part ofour galactic home; it is a veritable jewel box of stellarbodies in such profusion as to stagger the imagination.If this is the only thing you will ever see through atelescope, then it is no exaggeration to say you willremember the sight for the rest of your days.

Messier must have thought them so obvious as to benot worth mentioning, an odd thing to do when hecatalogued the Pleiades as M45, but he did not miss outon another showpiece cluster that now bears his stamp,M34. This cluster is approximately the size of the fullMoon, containing 50 stars of 6th-10th magnitude in arich field that is easily visible in binoculars. Messier 34lies over 1,500 light years away and contains over 400stars of which the above brightest 30-50 can be seen insmall telescopes. Astrophysical studies of Messier 34


The jewelsof PerseusMartin Griffiths describes the

wonders that can be seen in theconstellation of Perseus.

▲ Perseus constellation map. Credit: Torsten Bronger.

▼ The Double Cluster NGC 869 and NGC 884. Credit: Martin Griffiths.


have revealed at least 19 white dwarf stars, indicatingthat the cluster must be close to one billion years oldand once contained stars that were 5 or 6 times largerthan the Sun that evolved quickly and became planetarynebulae. Today no such object graces the stars of M34but in future years it may be worth keeping an eye onthe system for protoplanetary nebulae.

If you follow a line from Algol, back up to α Persei, youwill encounter a rich field of stars that steadilyagglomerate into a small but interesting cluster of 30 orso stars called NGC 1245. Discovered by WilliamHerschel in 1786, it has over 200 members and can beseen in 10 x 50 binoculars. The field is worth regularexploration as several bright novae have occurred herein the past, and may readily do so at any time again, sokeep an eye on it! NGC 1245 is at the amazing distanceof 9,800 light years so its members must be brightgiants.

Where the eastern arm of Perseus curves around,there are several interesting star clusters worthobserving. The finest of these is NGC 1528, a smallcluster of 40 bright stars just above the curve of thearm. This group is again relatively distant at 2,500 lightyears but it has an integrated magnitude of +7.5,making it an easy object for binoculars, although theview through a telescope is more rewarding. WilliamHerschel discovered this cluster and the relativelycloseby cluster, NGC 1545 in 1790. NGC 1545, at adistance of 2,350 light years is a small but rich littleasterism of 20 stars that is worth taking the trouble tofind and its brightest member is an orange K5 IIIsupergiant that can be seen as a coloured star in

binoculars shining at magnitude +7.8.Returning to the rich area of the Milky Way around

the double cluster, the observer can spot just to the eastof the two groups a smaller, dimmer collection of starsthat melt into the starry background. This is the starcluster NGC 957. Discovered in 1831 by John Herschel,the group lying at a distance of almost 6,000 light yearsand shines with an integrated magnitude of +8.1.Telescopes reveal about 20 stars surrounded by a fainthalo of starry points that flow into the Milky Way in apattern that at first sight seems rather scattered untilone becomes accustomed to looking at the group where aroughly rectangular outline to the object can beperceived. Visually, the brightest stars make out a littleletter – the Greek lowercase lambda (λ) – that should beeasy to spot as can be seen, in the image below left.

Not far away to the south east is the tiny little clusterTrumpler 2 which is marked on Sky Atlas 2000 and issurprisingly bright at magnitude +6.1. Some observerseven report being able to see this tiny knot of stars withthe naked eye but I find that binoculars or a smalltelescope bring out the stark beauty of its few stars.

Trumpler 2 is 2,000 light years away and has a lovelyorange red K III star at the centre of its scattered group.

Perseus contains some beautiful star clusters andnebulae, but the nebulae are generally faint andindistinct whereas its star clusters shine out against thebackground of the Milky Way like studded diamondsagainst a silvery backdrop.

Additional star clusters that are worthy of interest areNGC 744, NGC 1220, NGC 1342 and NGC 1513, thoughit is so tempting to cross the border into Cassiopeia andCamelopardalis to seek out other star clusters of thePerseus arm of our galactic home. Nevertheless, one canlook forward to enjoying some of these jewels almost allyear round, so I hope this brief taster will whet yourappetite for the jewels of this superb constellation.

Martin Griffiths is an enthusiastic sciencecommunicator, writer and professional astronomer. He is

Director of the Brecon Beacons Observatory, a Dark SkyAmbassador for the Brecon Beacons National Park, a

committee member of the International Dark Sky ReserveSteering Groups of Snowdonia and Brecon Beacons

National Parks and a science presenter and consultantfor Dark Sky Wales.


▼ Star Cluster Trumpler 2. Credit: Deep Sky Survey 2,copyright 1993-1995 by the California Institute of Technology.

▼ Star Cluster NGC 957 showing the stars making theshape of the Greek letter lambda. Credit: Deep SkySurvey 2, copyright 1993-1995 by the CaliforniaInstitute of Technology.

▼ Star Cluster NGC 1245. Credit: Deep Sky Survey 2,copyright 1993-1995 by the California Institute of Technology..


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Why not combine a family holiday with some exciting astronomy? TheAlgarve is a popular holiday destination for all the family and COAA is onlya short drive from the beach. The records indicate that the Algarve is thesunniest corner of Europe and temperatures average 10°C warmer thanBritain.

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Popular Astronomy 17wwww.popastro.comJanuary - February 2017

Science,art andspacejunk

CITIZEN SCIENCEALICE SHEPPARD presents

public participation in space research

My workplace recently held a citizen science event atwhich one of the speakers told us that during the

Renaissance, art and science flourished together – and thathe considers the same to be happening today.

This is the case for Project Adrift, an interactive artproject on space junk. Its producers, Cath LeCouteur andNick Ryan, want to raise awareness of the problem oforbital debris. A cloud of 170 million-plus objects, includingdead satellites, pieces of spacecraft and equipment left overfrom losses and explosion, now circles the Earth – silent,small and sometimes deadly. The International SpaceStation regularly manoeuvres to avoid them, and ESA’sSentinal 1A satellite’s solar panels were impacted in 2016.

LeCouteur, an award-winning short filmmaker, has madea documentary about orbital debris which you can watch atprojectadrift.co.uk. From here you can also “adopt” threewell-known pieces of debris on Twitter: @VanguardAdrift,@FengyunAdrift and @SuitSatAdrift. These are able to tellyou their location, their speed, facts about themselves andhow they came to be there. Artificial intelligence will enablethem to reply to your tweets with status reports. Butbeyond these technical achievements, LeCouteur isfascinated by the emotions that orbital debris can evoke:awe, fear, loneliness, even love? They are human-made, yetout of our control, and making it harder rather than easierfor us to enter space.

Ryan, meanwhile, is developing a type of citizen art,starting from open databases which track the movements oforbital debris. Tracking these objects is not easy, explainsAlice Gorman, a space archaeologist and space junk expert,who thinks Project Adrift is “wonderful”. Space junk doesnot necessarily stay where we leave it. If low enough, it willbe dragged down by our atmosphere and hopefully burn up– though not always (on her blog, Zoharesque, Gorman hasa list of actions to keep safe and scientific should orbitaldebris come blazing down from the sky near you). Higherup, it can drift, or its orbit become erratic. It may bounce inand out of Lagrange points between the Earth and Moon, ordisappear altogether.

Still, several databases are publicly available, and Ryanand LeCouteur used celestrak.com and celestrak.com/satcatto create an Orbital Mechanic Simulator to predict wherethousands of objects will be at a given time. (Gorman also

recommends heavens-above.com.) Sadly, the OrbitalMechanic Simulator is too heavyweight to be made publiclyavailable – but Ryan, an audio specialist and composer, isrepresenting the objects with sound. And this is where youcan help.

Ryan asks the public to send in objects that remind themof space junk. It could be something shiny, poetic, or asordinary as clothing. He too is interested in the enigmatic,the inexplicable emotions, raised by space junk and bysound. And when he has 1,500 items, he will attach acontact microphone to each and drag them along a hardsurface. The sound each makes will represent a piece oforbital debris. Ryan has a 1.5 m cylinder with 1,500 grooves(large for low sounds and large pieces of space junk; smallfor high sounds and small pieces). You will be able to tunein and every time a piece of orbital debris passes overhead,you will hear one of the sounds, a sound chosen out of 1,500to represent that piece.

Project Adrift’s art is not direct representation, but it willcertainly be evocative, and, being art, it is intended toinvolve and to drive action. I asked Alice Gorman whataction citizens can take about space junk.

First, you can join the several citizens observing it, andthere is an amateur tracking station called SatTrackCamLeiden. Second, we can pressure governments and bothprivate and public space organisations to clear up theirmess. Although ESA, NASA and the UN have all publishedguidelines about space junk, as many as 40% of missionsignore these due to cost and a lack of policing.

“Historically, space has been seen as the very last frontier,ripe for colonial conquest,” Gorman wrote for TheConversation in April 2013. “Just as on Earth, themotivations for colonisation are not just about curiosity, oran ‘urge to explore’, but about finding new resources toexploit for terrestrial markets. The unstated rationalebehind this draws heavily on Western anthropocentric ideasof the mastery of creation — the assumption that the non-human world is there for our use. This instrumental view isstill very prevalent in the way the space industry justifiesits activities.”

Alice Sheppard has been involved with citizen science for9 years, first running the Galaxy Zoo discussion forum and

now working at UCL's Extreme Citizen Science department.

◄ Representation ofknown satellites and

objects orbiting Earth.Credit: ESA.


It is impossible to say when aninterest in “popular astronomy”

began, for a knowledge of theconstellations, seasons, and themotions of the astronomical bodiesgoes back to Stonehenge andbeyond. Geoffrey Chaucer’sCanterbury Tales (c. 1381) take itthat the reader knows the basicfeatures of the sky, as doShakespeare’s plays. Then in the16th and 17th centuries, popular

printed astrological almanacs firstbrought the basics of Ptolemy’sEarth-centred cosmos before a massreadership. A readership thatincluded shepherds, milk-maids,and working people – indeed,anyone who, by 1600, wassufficiently lettered to be able toread the English Bible, and who hada few pennies to spare.

One of the first social groups totake astronomy to heart was

Anglican clergymen, especially afterabout 1660. These men were well-educated, had some spare cash andleisure time, and often took a delightin using and owning telescopes,accurate clocks, quadrants, andother scientific instruments. Theyobserved and timed eclipses and startransits, studied the surface of theMoon and planets, monitored theappearance of comets, andfrequently ran a local time service;their instruments determining thetime at which to set the parishchurch clock. Lots of thesegentlemen survive in the historicalrecord, such as the Revds. MrWalton and Mr Burgess ofWaddesdon near Aylesbury, whowere giving popular astronomyclasses to working people in the1850s.

It was one such serious amateurastronomer who became theastronomical ancestor of the late SirPatrick Moore. This was the Revd.Thomas William Webb, Vicar ofHardwicke, a rural parish on theborder between Herefordshire andSouth Wales. Thomas Webb alreadyhad a passion for astronomy whenhe was an undergraduate atMagdalen College, Oxford, in the1820s, and would go on to be theinspiration of countless amateur


The originsof popularastronomyDr Allan Chapman tells us the

history of how astronomybecame popular.

▼ Planisphere fromAstronomicum Caesarium

(Petrus Apianus) c.1540.Credit: Royal Astronomical

Society.

▼ Illuminated illustration of the Ptolemaic geocentric conception of the Universeby Portuguese cosmographer and cartographer Bartolomeu. From his workCosmographia, made in France, 1568. Credit: Bartolomeu Velho/Public Domain.


astronomers.Although a wealthy man in his

own right, Thomas Webb was notespecially drawn to high-level“Grand Amateur” fundamentalastronomical research intoplanetary dynamics or cosmology.Instead, what he enjoyed wasobserving, and delighting in, thesheer glory and beauty of the nightsky, using relatively modestinstruments, and encouragingothers to do so as well. Needless tosay, he knew the night sky like theback of his hand, and was fullyinformed of all the mathematicaltheory that lay behind contemporaryresearch, which made him an idealpopular astronomical communicator.

Webb’s Celestial Objects forCommon Telescopes (1859) wasdestined to become the touchstone ofthe new generation of Victorianpopular astronomers. It told you allyou needed to know about how to getstarted, complete with star andMoon maps, detailed discussions ofthe constellations, double, coloured,and variable stars of especial note,“nebulae” and where to find them,Right Ascensions, Declinations,planets, asteroids, comets, and soon.

It says something about the cost ofastronomical-quality refractingtelescopes of that time, however,

that the “common telescopes”referred to by Webb – three- or four-inch refractors of five feet focallength – would cost at least £25apiece second-hand, or about sixmonths’ wages for a working man.On the other hand, one might makean instrument. Webb also becamethe great advocate of what would bethe “standard” amateur’s telescope:the six- to nine-inch-aperturesilvered glass Newtonian reflector.

One such reflector was made forWebb around 1860 by George With,a schoolmaster of Hereford and apioneer and advocate of the newsilver-on-glass mirror reflectingtelescope. Now all of a sudden, bythe late 1850s, it was possible forskilful amateur astronomers to buya piece of thick plate glass for a fewshillings, and then figure it into aparabolic mirror, silver it, build awooden stand – and begin to worktheir way across the night sky! TheEnglish Mechanic magazine after1865 began to carry all manner ofadvice and practical tips for aspiringtelescope makers, while CaptainWilliam Noble would come to writeregular articles on popularastronomy.

But just like Sir Patrick Moore, theRevd. Thomas Webb had all kinds ofpeople writing to him aboutastronomy and seeking practicaladvice. His Celestial Objects becamea best-seller, and his astronomicalprotégé and clerical colleague, theRevd. Theodore H. E. C. Espin,revised and edited a sixth edition in1917.

Webb certainly gave lectures onastronomy, but the man who cameto epitomise “popular astronomy” inthe late Victorian and Edwardian

age was that colourful Irishman SirRobert Stawell Ball. The world wasmoving fast by 1870, with railways,electric telegraphs, photography,and mass-circulating newspapers,magazines, and books, and with it, anew breed of popular lecturers werebeginning to make a good livingfrom fee-paying astronomy “shows”.

Sir Robert Ball was born into awell-to-do Dublin professionalfamily, and was both a student, thenAndrews Professor of Astronomy, atthe prestigious Trinity CollegeDublin. In addition to being Directorof the Dunsink Observatory, Dublin,and a fine astronomical observer,Ball had a genius for teaching: notonly the high-level teaching of theUniversity, but also popularastronomy.

England’s rapidly-growingpopulation by the 1870s craved bothentertainment and easily-digestibleinformation on interesting topics –and Ball could supply both. Neweducational technology also wasbecoming available. The electric-arclight source, for example, now madeit possible for a “magic lantern” slideprojector to throw a bright imageonto a screen from 100 feet awayacross a large theatre. Glass-negative photography, therefore,enabled a popular lecturer like Ballto delight a packed theatreauditorium with a detailed image ofthe Moon, or Saturn, that was tenfeet across! Breath-taking stuff,indeed, for an audience paying a fewpennies per head at the box office.

When not teaching andresearching in Dublin, and laterCambridge, Ball undertook lecturetours around Great Britain, and by1884, Canada and the USA, as fast,


► Revd. Thomas William Webb's 9.25-inchaperture reflector from the mid-1860s.

Its silver-on-glass mirror wasmade for Webb by George Henry With,

a Hereford schoolmaster.

The mount was known as a ‘BerthonEquestrian Equatorial’, deriving from its

inventor, the Revd. Edward Lyon Berthon,and called ‘equestrian’ from the pair of

heavy counterweights which resembledriding stirrups. The instrument rotated

around a metal plate so that the axis wasin the equatorial plane.

The drawing is by the author; AllanChapman.

▲ T. W. Webb, from the coverplate in the1917 edition of Celestial Objects for CommonTelescopes. Credit: T.W Webb/Public Domain.


comfortable ocean liners made itfeasible to cross the Atlantic in a fewdays. His travel diaries are packedwith fascinating information, suchas the new electric lighting inAmerican streets, telephones, andeven the luxury of electric fans andearly air-conditioning technology inNew York’s Madison SquareTheatre.

Another big star on the Victorianpopular astronomy circuit was theCambridge-educated RAS“controversialist” Richard AnthonyProctor. Unlike Ball, Proctor neverheld a prestigious astronomicalappointment, and used his talentsas an astronomical promoter tomake a good living, undertaking anAustralian and global lecture tour in1880. On this journey, he met andclearly enchanted Sallie DuffieldCrawley, a young American widow,who became Proctor’s second wife.Indeed, Proctor was an early “jet-set” astronomer, as he and Salliehad homes on both sides of theAtlantic. Yet Richard’s career wastragically cut short in New York in1888. He was coming from theirFlorida home to take a ship tolecture in England, caught YellowFever, and died. But Sallie steppedin, sailed to England, and deliveredall his scheduled lectures! Mary,Proctor’s daughter from his firstmarriage, became a celebratedpopular astronomer in her ownright, dying at the age of 95 in 1957.

Astronomy, trains, fast ships, and

photography notwithstanding, in1888 infectious diseases were stillthe biggest killer, although LouisPasteur’s new germ theory ofdisease would soon begin to changethat.

Proctor’s and Ball’s books are stilla pleasure to read, and like thelectures upon which they werebased, cover all the big astronomicalissues of the day. There is, of course,up-to-the-minute material about theMoon, planets, and comets, butmajor new discoveries in physics arethere as well, such as the newsciences of “solar” and“astrophysics”, in which thespectroscope revealed all manner offacts about the physics andchemistry of astronomical bodies of

which no one could have dreamt in1860.

And then, and especially followingSchiaparelli’s “discovery” of thecanals of Mars in 1877, thepossibility of life on other worldsbecame another hot topic whichseized the popular imagination: justas it does today. Then what are the“nebulae”, how vast is the Universe,and how far does it extend?Fascinating, thought-provokingsubjects that must have sparkedmany a conversation in the home,the pub, the chapel, and theworkplace amongst the people ofBirmingham, Manchester,Newcastle, and elsewhere, who piledinto the tramcars on smoky wetFebruary evenings to hear Sir


▲ Robert Stawell Ball. Credit: W. & D. Downey.(commons.wikimedia.org/wiki/File:Robert_Stawell_Ball.jpg),creativecommons.org/licenses/by/4.0/legalcode

▼ 1877 map of Mars showing the network of lines Schiaparelli called canali. Credit: Giovanni Schiaparelli/Public Domain.

▲ Dunsink Observatory. Established in 1783. Now home to the Astronomy & AstrophysicsSection of the Dublin Institute for Advanced Studies. On the right is the main building. Onthe left is the dome housing the 12-inch Grubb refractor. Copyright JP and licensed for reuse under CC-BYcSA-2.0.


Robert Ball hold forth in the TownHall or Corn Exchange!

No doubt sped on by popularlecturers and publications, popularastronomy began to diversify in thelate nineteenth century, with theformation of large amateurastronomical societies, such as thoseof Liverpool, Leeds, Belfast,Newcastle, and Manchester. Thesesocieties could work on many levels:a person might join in order to learnhow he or she might make atelescope and do serious observing;whereas another might be an“armchair” astronomer, who simplyenjoyed learning from the regularlectures. Then in 1890, the BritishAstronomical Association wasfounded, appealing mainly to peoplewho were already committedobservers.

Yet what all these amateursocieties also did was provide scopefor women: to observe, sit oncouncils, lecture, and write. FlorenceTaylor, Mary Bacon, Mary Proctor,and other women found their publicvoices in giving talks toastronomical societies, and some,such as Mary Proctor, made part oftheir income from it. And even ifthey did not lecture, womenastronomical writers, such as AgnesGiburne and Agnes Clerke, werepart of the astronomical scene by the1890s.

In the twentieth century,astronomy became ever morepopular, though ironically rarelytaught in formal school scienceclasses, leaving aspiring amateurastronomers dependent upon thesocieties and books for information.

By the 1930s, however, twoCambridge scientific Knights cameto represent popular astronomy tomost people, especially in GreatBritain. And both were ideallyqualified to present the momentousdiscoveries of Einstein, EdwinHubble, and others to popularaudiences, via books, lectures, or thenew mass media of “the wireless”, orradio. They were Sir Arthur StanleyEddington, and Sir James HopwoodJeans.

But the Universe of the 1930s wastruly a cosmos far removed from thesteady-state, single space-timecontinuum lectured upon by Balland Proctor. For Einstein’s GeneralTheory of Relativity, 1916, thefindings of the 100-inch Mt Wilsonreflector after 1917, Edwin Hubble’sdiscovery of stellar red shifts andCepheids in the Andromeda“nebula” (M31), 1924, and FatherGeorges Lemaître’s possiblyexpanding universe of 1927-30 hadshown deep space to be a verystrange place indeed.

The general public wanted to knowabout this bizarre “Alice inWonderland” cosmology in which allthe old rules had to be changed, andEddington and Jeans were the twotop-flight scientists who could “getthrough” to ordinary people.Eddington’s The Nature of thePhysical World (1926) and Jeans’sThe Mysterious Universe (1930)became worldwide best-sellers,while by the 1930s radio had givenpopular astronomy a new voice.

Radio talks on the new physics andcosmology, and the appearance ofeminent physicists on programmes

like the Brains Trust, couldtake Einstein’s and Hubble’sideas into the Welsh miner’sand the Highland crofter’scottages, if people were inclinedto “listen in”. And while a“proper” radio set was still veryexpensive for ordinary people,cheap “crystal sets”, assembledon the kitchen table from partsand instructions purchasedfrom the local hardware shop,did bring BBC Radio within thepurchasing range of workingfolk. (I still have my dad’shome-made crystal set of

c.1927, though he was more intodance bands than astronomy.)

By the early 1950s, television wasalso seen as possessing immenseeducative power, especially as thetelevised Coronation of H.M. QueenElizabeth II in 1953 had inspiredmany to save up and buy a family“telly”. Yet who was there who hadthe knowledge and the “flair” toenthuse and inspire people to look atthe heavens? After trying outvarious professional scientistswithout much success, in April 1957the BBC hit upon a 34-year-old ex-RAF officer then working as aschoolmaster. He was not a high-powered academic physicist, but avery experienced practical observingamateur astronomer. He was deeplyknowledgeable, articulate, eccentric,and utterly entertaining to watch.He would go on to present The Skyat Night for the next 55 years,become a Knight, an FRS and aglobal icon of popular astronomy.His name was Sir Patrick AlfredCaldwell Moore.

Dr Allan Chapman is a native ofSalford, Lancashire, and a historianof astronomy and medicine at OxfordUniversity. He was inspired as a boy

by Sir Patrick, and used a home-made cardboard telescope on a

tripod of old broom handles to showthe Moon to school chums and

neighbours. He is the author of adozen books, has made several TV

documentaries, and is HonoraryPresident of the Society for the

History of Astronomy, the WilliamHerschel Society, and the SalfordAstronomical Society, along withseveral others. His The Victorian

Amateur Astronomer: IndependentAstronomical Research in Britain

1820-1920 (1998) is due to bereprinted.


◄ Patrick Moore in his RAF uniform(early 1940s). Image courtesy of Chris Balcombe.


T here are lots of asteroids travellingaround the Solar System so why not

just hop on one and take a free ride?After all, the Philae probe's landing onthe surface of Comet 67P demonstratedthat landing on small space objects isdoable. But, and this is a big but, it tookten years from launch to landing, so thatbegs the question “is it worth all thateffort”?

In the case of Philae, the answer is“yes” because its scientific mission wasto study the comet as a relativelyunchanged remnant from when the SolarSystem was formed some 4.6 billionyears ago.

If you are simply doing it to hitch a ridethen the answer may be differentbecause you’d need to catch up with andmatch the course and speed of theasteroid. Having used all that fuel andeffort, why bother hitching a lift at allwhen you have done all the hard workalready? And are there enough asteroidspassing by our planet to make the ideafeasible?

According to NASA’s Near Earth Object(NEO) study, they have discovered 14,815NEOs, some 874 having a diameter ofone kilometre or larger. The study hasalso identified five asteroids that willpass from Earth to Mars before the year2100. So, suitable candidates are outthere.

There are also lots of asteroids orbitingthe Sun farther out, often with ellipticalorbits that may well get close enough tous to be useful. However, there is thelittle problem of altering their orbit tomake them useful to us. Fortunately,some work has already been done onthis and it looks feasible to nudge anasteroid into the desired path using agentle push for a long period, using asolar sail or some other means.

So what would make it worth theeffort? Number one is to be able to shieldastronauts from cosmic rays: a job thatconventional space craft are very bad at.Cosmic rays can damage human DNAand increase the risk of cancer andcataracts. Research suggests that during

a thousand-day round trip to Mars, anastronaut's cancer risk could beincreased by up to 19%. By using thebulk of the asteroid as a shield (maybeeven building accommodation below thesurface) we could greatly reduce threatsto health and also provide moreprotection from meteor strikes. Actually,in a spacecraft the aluminium used toshield current space vehicles can, overtime, produce secondary radiation worsethan the original hit from cosmic rays!So, in principle, Asteroid Life-SupportFacilities (ALFs) are a good idea.

Assuming that we have altered theasteroid’s orbit to pass by Earth and ourtarget planet at regular intervals, it wouldthen be worth making theaccommodation significantly larger andmore comfortable than on a conventionalspacecraft. Much as we have done withthe ISS, we could add to an asteroid’sfacilities over time by sending up supplyand construction missions each time itpasses by Earth. We could also addscientific labs and even manufacturingplants for the equipment we would needon the target planet. Given the rightconditions we could mine the asteroid formaterials.

Taking it one stage further, why notalter the orbit of other asteroids to makeregular trips from Mars to Jupiter andfrom Jupiter to Saturn and even fartherout. That way, we could have a "hop-on,hop-off" shuttle bus system to get usaround the Solar System. Maybe wecould even open up a market for cruise-style package holidays around the SolarSystem; or is that getting a bit too sci-fi?

The bottom line is that we could useasteroids for space travel and, even withour current technology, the task is notbeyond us. Whether “it is worth all thateffort” is still debatable but we shouldnot rule it out.


Hop on anasteroid

by Alan Ackerley

▲ A hypothetical attempt to hitch a lift aboard the NEO Eros, 34 km indiameter, as it passes Earth. Photo: Robin Scagell/JHU/NASA.


Asteroid: There are millions of these small rocky bodies in theSolar System, mostly between Mars and Jupiter.

Slingshot effect: Jupiter’s gravitypulls a spacecraft towards it. So ifa spacecraft comes up behindJupiter as Jupiter moves towardsthe Sun, this speeds the spacecraftup.

Deflection: This is when gravity pulls a rocket – or anything else– off course. This has thrown comets out of the Solar System!

Rogue planet: A planet not in a Solar System. Actually, there’sno reason why any should be full of uranium, but I did want toput in something nice.

Molecular cloud: When there isenough dust in space, it blockslight, and so cools down inside.Matter mostly exists as lone atomsin space, but molecules can forminside these clouds. This is alsowhere stars are born.

Black hole: An object so heavy that nothing, no matter how fastit is, can escape its gravity.

Shockwave: When a big star explodes, it can throw gases out at30,000 km/s! This in turn hits all the gas and dust in the spacearound it.

Relativistic jet: Matter spinninginto a black hole forms a very hotdisc. At right angles to this disk,jets of matter come out so fastthat the theory of relativitybecomes important (e.g. particlesin them get heavier).

Hypervelocity star: Most stars are in binary systems – two starsspinning around each other. If one star dies or shrinks, theother can fly off – as if you were spinning a brick on a stringaround your head, then let go of the string. Some of these starszoom right out of their home galaxy. In real life, it’s prettyunlikely we could get near one of these safely, but it’s a funthought!

Magnetar: a pulsar (spinningneutron star) with some liquidinside it that generates amagnetic field as it spins – thesame way as the Earth’smagnetic field is generated, butit’s millions of times stronger.Besides being enough to eatyour parents’ credit card from100,000 kilometres away, it alsoemits strong X-rays.

Time dilation: If you go REALLY fast, your time relative to others’slows down. But that’s a story for another article ….

From Lucie Green,Chief Stargazer

T he first asteroid was discovered in 1801 and given the name Ceres. This asteroid isjust 950 km in diameter but remains the largest of the many thousands that are

now known about. And even though we have been observing asteroids for almost 200years, they are still fascinating to us today. Asteroids can have comet-like tails, havebeen captured by planets to form moons like Phobos and Deimos, and in the futurethey might provide valuable mining resources for us when supplies on Earth run out. Afew years ago I remember watching the small asteroid 2012 DA14, just 45 m across, flypast us, closer to the Earth than the Moon is. This space rock went safely by, but it wasa reminder the Earth has been struck by asteroids in the past and will be again in the future. It’s just a matter of time.

In this issue you’ll learn about a new role that asteroids could take on – that of a ready made space station! We need tokeep observing asteroids for all sorts of reasons.

Happy Stargazing!

January - February 2017

Space Hazards! by Alice Sheppard

On the next page, you’ll find a board game with just a few of space’s terrible dangers in it. This is why engineershave to plan so carefully, to avoid some of the following hazards, which you will meet in the game….

▲Artisits impression of a relativistic jet.Credit: D. BERRY (STSCI).

▲ A molecualr could from the Carina Nebula. Credit: Hubble Heritage Team (STScI/AURA),

N. Walborn (STScI) & R. Barbß (La Plata Obs.), NASA.

▲ Jupiter with two of its moons, Io and Ganymede. Credit:NASA/Damian Peach, Amateur Astronomer.

▲ An artist’s impression of amagnetar in the star cluster

Westerlund 1. Credit: ESO/L. Calçada.

www.popastro.com Popular Astronomy 23


Rocket Race! TY

2+ players

EARTH

START!Not enough fuel! Return to Earth and try again.

OUCH!! You’re out!


BOOST!!Double your next score!


Deflected!!Return to Earth and start again!

Slow down!!Halve your next 2 moves.

Credits: Earth: NASA, background: ESO/S. Brunier, Jupiter: NASA, ESA, and A. Simon, Neptune: NASA, exoplanet: NASA Ames/SETI Institute/JPL-Caltech, ESA rocket: ESA/David Durcros, SpaceX rocket: SpaceX. Game by Alice Sheppard. Layout by Jo L

You hit an asteroid and your rocket is completely smashed!

You go past Jupiter and use the slingshot effect to go much faster!

A nearby star goes sThe shockwave dammotor!

You go through a giamolecular cloud. Youbeing born, but it’s d

You go through thejet of a quasar. Youcompletely fried!

You manage to gethypervelocity star agravity to increase

Oh no, you went tooa black hole; we’ll nyou ever again!

Neptune deflects your path, sending you back towards the Sun!

You find a rogue planet with lots of useful uranium for your motor!

EAEAARRTTHfuel! arthn.

You hit anr

To play:You need:

You are in a rocket trying to reach a habitable planet! Whoever arrives first wins.1 dice; some counters (they can be anything – 1 per player). Start at Earth; roll the dice to move boldly along the board to where no Young Stargazer has ever gone before. If you get 'halve your next move' but you're on an odd number, just halve it then add 1/2. So if you're on 3, halve it (1½) and add ½ so it becomes 2.

!! t!





WHOOPS!!Count back-wards this turn.

Slow down!!Halve your next move.

Sheppard. Layout by Jo Law.

by star goes supernova! ockwave damages your

through a giant ar cloud. You see stars orn, but it’s dangerous.

through the relativistic quasar. Your rocket is

etely fried!

anage to get behind a elocity star and use its to increase your speed!

you went too close to hole; we’ll never see

er again!

You couldn’t decelerate fast enough! You’ll have to go round in a circle.

Congratulations, you have reached the habitable planet! Only thing is, your friends on Earth are old and their computers can’t read your Snapchat photos!

You find a rogue planet with lots of useful uranium for your motor!

You get too close to a magnetar! All the iron in your rocket and your blood are ripped out!

PLANETFINISH!

Although most professional astronomers rarely visittelescopes these days, spending most of their

working lives in anonymous office buildings onuniversity campuses, some of us are lucky enough towork at operational observatories. In my case, theobservatory is Jodrell Bank in Cheshire, part of theUniversity of Manchester. As radio telescopes canoperate during daylight as well as by night, most radioastronomers keep fairly normal office hours, so it's 9 amon Monday morning when I arrive at the office.

Just as artificial light makes it harder for opticalastronomers to see the stars, radio transmissions makeit difficult for our telescopes to see the radio sky. Ourtelescopes are so sensitive that any nearby mobilephones (or other sources of radio waves, such as wifi,microwave ovens, fluorescent light bulbs) can causeserious interference – the less interference I cause withmy gadgets, the less time I have to spend removingthese signals from my observations, so my phone getsswitched to flight mode as soon as I leave the house!

There is no such thing as a typical day at theobservatory, but there are many things that are fairlyroutine. Monday usually involves checking the datafrom observations made over the weekend, talking tothe telescope controllers who monitor the status of theequipment to find out if any of our telescopesmalfunctioned, or if the weather meant thatobservations had to be stopped.

As you may know, we don't just operate one telescopeat Jodrell Bank. In fact, the controllers look after ninetelescopes altogether. One is a teaching telescope, one isused to study pulsars, and the other seven operate as asingle instrument, making up an array 217 kilometresin diameter. This network, a national facility known asthe electronic Multi-Element Remote-LinkedInterferometer Network (e-MERLIN), can make radioimages of galaxies with the same resolution as theHubble Space Telescope can do in the optical part of theelectromagnetic spectrum.

A large part of my job involves working with e-MERLIN.A few years ago I wrote the software package which isused to process all data from the array, and I still


A day in thelife of a radioastronomer

Dr Megan Argo writes about what it's like towork at the Jodrell Bank Observatory.

▲ The Lovell telescope, one of ninetelescopes operated from Jodrell BankObservatory. All images credit: Megan Argo.

► Sunset over the Lovell telescope (right) and the smaller Mk2telescope (left), one of the e-MERLIN antennas.


modify and update this software as thingschange, or when users submit bugreports. But I also spend a lot of myworking day processing data from e-MERLIN, using the high sensitivity andexcellent resolution to study nearbyinteracting galaxies, and activesupermassive black holes in the distantUniverse.

The Universe is a big place and we canoften only understand it fully bycombining observations across thespectrum. Much of science is done bycollaborations of researchers withdifferent areas of expertise, all workingtogether to try to solve a problem. Oneproject I am spending a lot of timeworking on at the moment is looking at anew and very bright radio source in anearby galaxy. The evidence we havecollected strongly suggests that the newsource of radio emission is the centralsupermassive black hole. Together withresearchers in Southampton and theNetherlands, we are trying to understandwhat caused the black hole to suddenly become active,and how much energy is being released into the galaxyby measuring the speed of the jets. This requires evenbetter resolution than e-MERLIN can provide, so we areusing a European network of radio telescopes to createan array some 10,000 kilometres in diameter, with aresolution of just five milliarcseconds – that would beenough to see craters on the Moon as small as tenmetres in diameter!

One of the most enjoyable parts of my job is teachingstudents. During the summer, I worked with two highschool students on the Nuffield Research Placementscheme, where they spent six weeks in a universitylaboratory working on a short research project, gettingsome hands-on experience of what it is like to be ascientist. The two students working with me used new

data from two sets of telescopes to make images of tworeally interesting sets of colliding galaxies so that wecan try to measure their rates of star formation. Asthese students are very new to research, I spent sometime each day talking to them about the project, andanswering their questions about life as a scientist.

Of course, there isn't much point doing amazingscience if we don't then tell the rest of the world aboutour exciting results, so a large part of doing science isactually communication. Once the measurements havebeen made and the analysis completed, the next step isto write up the results to be published in an academicjournal. Papers submitted to these journals go through aprocess called peer review, where each paper gets sentto another expert in the field who will read it thoroughlyand check the results and scientific conclusions. For

students this can be quite a dauntingprospect, the thought of a well-established expert reading through theirwork is a bit intimidating. Recently, oneof our second-year students submittedher first paper, and this week a recentgraduate also submitted his. A crowd ofus took them out for a pub lunch tocelebrate!

That's the way science works in theend, the accumulation of lots ofcontributions by scientists around theworld, slowly pushing back theboundaries of our knowledge, one day ata time.

Dr Megan Argo is a radio astronomerwho worked at Jodrell Bank (Universityof Manchester) between 2013 and 2016.

Since writing this article she has movedon to become a lecturer in astronomy at

the University of Central Lancashire(although she still visits Jodrell Bank

from time to time).


▲ Megan Argo having a tea break at the Observatory.

▼ A view over the Cheshire Plains from a walkway under the bowl of the Lovell telescope.


Back in July it was revealedthat the Sun’s closest stellar

neighbour Proxima Centauri, ared-dwarf star, plays host to anexoplanet now named Proxima b.Astronomers had evidence for theexoplanet in previous data, butstruggled to agree on its orbitalperiod until follow up observationswere completed at the La Sillaobservatory in Chile. Lyingcomfortably within its star’shabitable zone with a masscomparable to the inner rockyplanets of our own Solar System,Proxima b shares keycharacteristics with the Earth –something of which has inspired

several scientists to flag theplanet as being potentiallyhabitable, but what else must beconsidered before deciding uponthe habitability of a planet?

Traditionally, the two mainindicators for habitability are: theexistence of liquid water on theplanet’s surface and its ability tosustain an atmosphere. Liquidwater is known for being a vitalingredient for life on Earth and itsexistence is dependent uponlocation: the planet must be in thehabitable zone. For a star likeProxima Centauri, an exoplanetmust have an orbital periodbetween 4 and 14 days to be found

within the habitable zone. Taking11.2 days to complete its journeyaround Proxima Centauri placesProxima b in this “Goldilocks”region, meaning the averagetemperature on Proxima b may be“just right” and it is possible forliquid water to exist on its surface.The location of Proxima b, in aclose orbit around its host, isperfect for liquid water, but sadlyit is less ideal for the secondingredient required forhabitability – an atmosphere.

Existing in such a close-in orbitmeans Proxima b is subjected toUV and X-ray flares often 400times stronger than those

28 Popular Astronomy

Is Proxima b habitable?

A planet has recently been discovered orbiting our closeststellar neighbour, Proxima Centauri.

Amber Hornsby asks

▼ An artist’s impression showing the planet Proximab orbiting the red dwarf star Proxima Centauri withthe double star Alpha Centauri AB in the distance.Credit: ESO/M. Kornmesser.

www.popastro.com January - February 2017


experienced on Earth, which couldbe very damaging to the planet’satmosphere and any inhabitants.Remember that our atmosphereon Earth blocks around 77% of allUV radiation, yet we still oftenrequire protection from its effects.Another complication for thehabitability of Proxima b is that itis tidally-locked, which means thesame side of the planet alwaysfaces its host star. Thankfully,simulations of similar planetarysystems indicate that magneticfields in tidally-locked planets canbe strong enough to prevent theatmosphere from being erodedaway. Recent studies suggest thateven a thin atmosphere in atidally-locked planet is sufficientfor heat redistribution leading to astable climate.

It’s not all doom and gloom forProxima b if it struggles to retainan atmosphere, but it wouldrequire a certain amount ofadaptation from extra-terrestriallife. When I spoke to Dr JackO’Malley-James of CornellUniversity, he said “Life on Earthhas evolved many ways of dealingwith UV, such as livingunderground, or within rocks, orunderwater”. On Earth there arecertain species of coral reefscontaining special proteins whichabsorb harmful UV rays and re-emit light at a longer, saferwavelength which protects thecoral. If such a mechanism hadevolved on Proxima b, modelsactually suggest that thebiofluorescent glow could bedetected from Earth – iftechnology advances amply.

The next challenge for thescientific community is to confirmhabitability of Proxima b, andother candidates, using moderntechniques such as direct imagingand spectroscopy. The nextgeneration of large ground-basedtelescopes – like the European-Extremely Large Telescope(E-ELT) – will help further thespectacular work in direct imagingalready being completed by twodifferent instuments in Chile: theGemini Planet Imager (GPI) andthe Spectro-Polarimetric High-contrast Exoplanet Research

www.popastro.comJanuary - February 2017 Popular Astronomy 29

▲ The habitable zone, shown here in green, is the region around a star where the temperatureis just right for liquid water to exist on the surface of a planet.Credit: Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley.

▲ This infographic compares the orbit of the planet around Proxima Centauri (Proxima b) withthe same region of the Solar System. Proxima Centauri is smaller and cooler than the Sun andthe planet orbits much closer to its star than Mercury. As a result it lies well within thehabitable zone, where liquid water can exist on the planet’s surface.Credit:ESO/M. Kornmesser/G. Coleman.

▲ This plot shows how the motion of Proxima Centauri towards and away from Earth ischanging with time. This regular pattern of changing radial velocities repeats with a period of11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated thepresence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 millionkilometres from Proxima Centauri — only 5% of the Earth-Sun distance. Credit: ESO/G.Anglada-Escudé.


(SPHERE) at the VLT. Bothemploy a coronagraph to block outthe host star for imaging, andadaptive optics to allow forspectroscopic measurementsrevealing the constituents of theatmosphere. Probing theatmosphere of exoplanets isn’tnew, but previously suchmeasurements could only occur ifthe planet passed in front of itsstar. Once launched, the directimaging capabilities of the JamesWebb Space Telescope will be ableto probe the infrared region ofexoplanetary atmospheres –something not possible from theground because of our ownatmosphere. This is clearly anexciting region for habitability ifwe want to find an Earth 2.0 witha breathable atmosphere.

Studying Proxima b from adistance will provide great insightinto whether or not it is a

habitable planet, yet we may stillbe provided with the opportunityfor a closer look. Proposed byStephen Hawking, MarkZuckerberg and Yuri Milner (aphysicist, prolific investor, andfounder of mail.ru), BreakthroughStarshot aims to send ultra-lightnanocrafts, travelling at asignificant fraction of the speed oflight, for a flyby of ourneighbouring star system, AlphaCentauri, while beaming homeimages within 20 years of launch– with Proxima b as a primetarget. Clearly many technologicaladvances will need to occur forthis to be possible but nothingwould confirm habitability likeclose-up images of a planetarysystem and its potentialinhabitants.

Is Proxima b habitable? Theanswer is maybe, but it is tooearly to tell. For every indicator

scientists find, there are severaltheories and models for andagainst habitability which seemas equally likely as the next.Luckily for us, Proxima b is, ongalactic scales at least, next door,providing scientists with afantastic opportunity to study apotentially habitable exoplanetlikely to be our first stop ifinterstellar travel one daybecomes a reality. So while wedon’t yet know whether Proxima bis habitable, its location so close toour own Solar System means thatit will be a key candidate for studyand play a vital role in thedevelopment of exoplanet sciencein the coming years and decades.

Amber Hornsby is apostgraduate researcher at CardiffUniversity, who is working on new

instrumentation to probe the sub-millimetre Universe.


▼ This picture shows the southern skies over the ESO 3.6-metre telescope at the La Silla Observatory in Chile with the constellations marked toaid identification. The orange target marks the position of Proxima Centauri. The yellow target marks the position of double star AlphaCentauri AB. Proxima Centauri is the closest star to the Solar System and is orbited by the planet Proxima b, which was discovered using theHARPS instrument on the ESO 3.6-metre telescope.Credit: Y. Beletsky (LCO)/ESO/ESA/NASA/M. Zamani.


SPACE EXPLORATION

TGO released the Schiaparellilander on 16 October, touching

down onto the Martian surface 3 dayslater in the same location where theExoMars rover may end up in a fewyears (hopefully 2020). The landingwas in a similar style to how theHuygens satellite approached Titan,with a parachute and heat-shield, plusthrusters rather like Curiosity’slanding, and with an extra crushablestructure to cushion the rest of thelander from the impact (like thecrumple zone in a car). This was animportant test for ESA of itstechnology for a controlled descent andsafe landing, in preparation for futuremissions.

It is a great shame Schiaparelli didnot land safely, but the technology didwork at the basic level; that is goodseparation, good targeting, parachuteopening, and rockets firing. It crashedsufficiently close to the plannedposition (around 5 km away) thatimages were quickly obtained byorbiting satellites, and its telemetryduring the descent had been receivedsafely. This all helps the Board ofInquiry to find what went wrong.

While Schiaparelli was attemptingits landing, TGO was executing its

engine burn to enter orbit aroundMars. The initial orbit is highlyeccentric from a few hundredkilometres above the surface atperigee to nearly a hundred thousandkilometres at apogee, taking four sols(Mars’ days) to complete one orbit ofthe planet. TGO’s orbit will begradually changed to a circular orbit400 km above the surface, taking onesol to complete. It will need about oneyear to complete the orbit changesbecause TGO will use aerobraking toslow the satellite down to make theadjustments to the orbit. Thispreserves fuel, and it also allowsscientists to study the density of Mars’atmosphere, in preparation for latermissions. Only then will TGO’s

scientific mission start, as it makes adetailed study of the atmosphericgases, especially the rare gases suchas methane. Studies from the groundand data from ESA’s Mars Expresssatellite suggest that methane comesand goes, depending on the season andon the location, and the cause of theproduction is unknown (geological orbiological or “other”). TGO will join thefleet of satellites in orbit around Marsable to act as relay stations fortransmissions from the rovers on thesurface.


ExoMars Trace Gas Orbiterand Schiaparelli lander

HELEN WALKER reports on astronautics,spaceflight and space exploration

There is news from Airbus Safran Launchers (ASL) that the Ariane 6could be ready for use in 2020, following an extensive review by ESA. It

will halve Ariane 5’s cost of putting satellites into orbit, having transformedits production processes. This may be an unintended consequence of the USAintroducing commercial launchers such as SpaceX and Falcon 9. BlueOrigin’s boss has unveiled his plans for his next rocket called the “NewGlenn”, which he hopes will launch satellites in the next few years. Thisjoins his very successful sub-orbital rocket “New Shepard” which has nowsuccessfully returned to Earth safely on its last four occasions; it is amazingto watch the rocket landing on its thruster and doing trim manoeuvres tokeep upright all the way down to the landing pad. China has launched asecond experimental space station, Tiangong 2, and hope to use it as a crewoutpost by 2022. It is about 15 m long, and can have other missions dockwith it. The prototype Tiangong 1, launched in 2011, was smaller and will re-enter this year, from its orbit below that of the International Space Station.

You may have missed an amazing set of travel posters produced by JPL,advertising holiday destinations such as Europa, Kepler 16b, HD 40307 getc. – check it out! www.jpl.nasa.gov/news/news.php?feature=5052.

Launchers and landings

► Composite of the ExoMars Schiaparellimodule elements seen by NASA’s Mars

Reconnaissance Orbiter High ResolutionImaging Science Experiment (HiRISE). The

main impact site is seen top. The region withthe parachute and rear heatshield is bottom

left. These were captured in the centralportion of the HiRISE imaging swath that

is imaged through three different filters,enabling a colour image to be constructed.

The front heatshield (bottom right) liesoutside the central colour imaging swath.

Credit:NASA/JPL-Caltech/University of Arizona.


SPACE EXPLORATION

Curiosity has received anothertwo-year extension to its

mission and is now climbing in thefoothills of Mount Sharp. Themountain has many layers visibleand Curiosity is still finding areasrich in iron oxide and also clay-richbedrock, both of which form in wetconditions, as it makes its wayever higher towards younger rocks.The higher Curiosity goes andfinds rocks like these, it impliesthe longer the lakes in Gale Craterpersisted, presenting potentialhabitable conditions. Its mainmission has already beenaccomplished in that Curiosity

found evidence of water on theearly Mars, evidence of ancientrivers and lakes, and the chemicalingredients to make the ancientlakes suitable for some form ofprimitive life to develop. Now it isstudying the duration of theseconditions, and still producingsurprises.

Opportunity, now 12 years oldand maybe inspired by Curiosity’sadventures, is also starting toclimb, in this case into EndeavourCrater. It has studied features onthe rim for the last five years andis now heading into a gully whichslices through the rim, carved a

long time ago possibly by water.These “fluid-carved” gullies havebeen observed in many places onMars, but this is the first time arover has reached one, can getinside it, and drive down thelength. The gully might have beenformed by a flash flood, perhapsdue an asteroid impact meltingunderground ice and creatingdebris, or it might have beenexcavated by a flow of mostlywater and not much else.Opportunity’s studies in the gullycan later be compared with newdata from the crater floor itself,further downhill.


Curiosity and Opportunity still going strong

▼ This self-portrait of NASA's Curiosity Mars rover shows thevehicle at the “Quela” drilling location in the “Murray Buttes”

area on lower Mount Sharp. Credit: NASA/JPL-Caltech/MSSS.


SPACE EXPLORATION

ESA’s Rosetta satellite has “safely” crashed into theComet 67P/Churyumov-Gerasimenko and the

mission is over. You can understand the feelings of theengineers at the European Space Operations Centre inGermany, deliberately driving their satellite into thecomet having worked so hard to keep it out of harm’sway for over ten years. It was a time for tears ratherthan cheers. Rosetta has done an amazing job, from themoment it woke up and worked after 31 months of deephibernation on the trip out to Comet 67P. Even at thelast moment, science took priority, as Rosetta headed fora very close pass over the mysterious pits, with the

goose-bumps visible inside, and landed in the Ma’at areaon the head of the duck. The Philae lander had earliertouched down in the Agilkia region, then taken off forfour hours and finally ended up in the shade against acliff face at Abydos. Philae provided enough informationabout its flight for the lander to be eventually imaged byRosetta. Rosetta’s cameras had detected 34 outburstsaround perihelion: these are the events which cause thecomet to brighten noticeably, even though they may lastonly five to thirty minutes. It is these types of outburstsfrom comets, together with the jets, that make usbelieve comets are rich in water ice. Rosetta showed thatthe surface of the comet was dark with dust andboulders all around, so scientists found there was muchmore dust, and less water, in the comet than expected.Another surprise was the detection of molecular oxygenand nitrogen, both very rare molecules for a primitiveobject like a comet. (Molecular oxygen is normally splitup into atoms by the Sun’s ultraviolet light.) Theamount of deuterium (heavy hydrogen) in the ice alsosuggest that Comet 67P was originally part of the cloudof material left over as the planets formed, and notmuch changed after that.


Goodbye toRosetta

▲Sequence of images captured by Rosetta during itsdescent to the surface of Comet 67P/C-G on 30 September.Credit: ESA/Rosetta/MPS for OSIRIS TeamMPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Scientists from Brown University in the USA suggest theMare Imbrium is the result of an asteroid 250 to 300 km

across impacting the surface. This is an asteroid twice as large indiameter and ten times as massive as previous estimates. Theasteroid hit at an oblique angle, which explains some mysteriousgrooves near the crater, and these were used to help estimate theasteroid’s size. Using the Vertical Gun Range in America, thescientists showed that pieces of the asteroid probably sheared offat the initial contact, scouring the surface before the main impactso they point back along the trajectory rather than radiatingoutwards from the crater itself. They have identified othercraters on the far side of the Moon which could have been formedby asteroids larger than 100 km across impacting. There is somewater on/in the Moon, which may have been brought there byasteroids and trapped in the cooling magma after the impact.Volcanic activity eventually brought some of the rock back to thesurface. Rocks brought back to Earth by Apollo astronauts havebeen studied by scientists at the Open University, and theanalysis of the water showed that asteroids (in particularcarbonaceous chondrites) were the most likely candidate, ratherthan comets or the Earth. This would mean that the impactsoccurred early in the history of the Solar System.

The Moon and an asteroid impact

▲ Mare Imbrium on the Moon. Mosaic of photos byLunar Reconnaissance Orbiter. Credit: NASA/LRO.

s thettes” SSS.



BOOK REVIEWS

Over the last century, our understanding of theCosmos has increased at an astounding rate. We’ve

progressed from believing that the Milky Way was ourentire Universe, to observing thousands of galaxieswhich cluster to form a giant web-like structure acrossour night sky. The Cosmic Web begins with thestatement “It is fair to say Edwin Hubble discovered theUniverse”, but like many of you, I have often wonderedabout this journey taken by science and the great mindsthat were involved.

Starting with Hubble, the author takes the reader onan exciting voyage from the Big Bang, through inflationbefore eventually evolving towards its ultimate fate. Wetackle the great Shapley-Curtis debate about our ownplace in the Milky Way, before speeding through to thebeautiful theories of the mighty Albert Einstein. By theearly 1980s, we catch up to the author’s earlyresearching days and witness how the field transitionsfrom observers making the breakthroughs, totheoreticians pushing the boundaries of physics withtheir extraordinary simulations. It is clearly anexhilarating time for all involved and the anecdotalnature of the writing makes you feel like you’re part ofthe team. At times, I found myself rooting for certain

physicists to succeed over their peers.At first I thought it was going to be a standard

cosmology book – interesting to read because of thesubject, but a little difficult at times due to complexity ofthe science. I was, however, pleasantly surprised. Withfunny chapter titles such as “meatballs in space” and “aswiss cheese universe”, it didn’t take long before Istarted to really enjoy reading this book whilst learninga thing or two about cosmology. The Cosmic Web is fullto the brim with wonderful analogies and genuinelyinteresting anecdotes that should be a component of allpopular science books. If you’ve ever looked up at thenight sky and wondered why it looks the way it does,this is one book you should really consider reading.

Amber Hornsby

Starlight is a view into the past. The light from onestar may take millions of years to reach Earth – and

the very oldest carry information about the earlyUniverse. Searching for the Oldest Stars is a book aboutthe hunt for these relic stars and what they might tellus.

Chapters are mostly self-contained such that the bookcan be read in parts, but is also easy to readcontinuously. Anna Frebel’s passion for what she calls“stellar archaeology” – determining a star’s makeup –shines through every page.

Determining a star’s chemical composition is no easyfeat, drawing on disciplines including nuclear physics,quantum mechanics and atmospheric physics. Frebeluses analogies throughout, which clearly explain manytopics otherwise difficult for nonspecialists. The book ismostly well-illustrated, with plenty of diagrams, graphsand helpful visual aids. There are also attractive colourplates covering telescopes, the evolution of the Universe,

stellar evolution, galaxies and optics.Searching for the Oldest Stars brims with detail; even

people familiar with most of the underlying science willfind much of interest. Frebel also highlights the roles ofmany otherwise unknown astronomers, especiallywomen who worked as “computers” and made importantscientific discoveries but still receive comparatively littlerecognition today.

What sets this book apart is how Frebel interweavesfacts with personal anecdotes. Few popular sciencebooks discuss the working life of a scientist; by contrast,Frebel fills the book with her photos, stories and evenextracts from her log book! She also discusses limits inresearch and unsolved problems in astrophysics. Notonly does she make the science clearer, but her writingshows that research is intense, passionate and veryhuman, not something removed from ordinaryexperience.

However, sometimes Frebel attempts to fit in too muchdetail, making her prose unclear; some passages have tobe read multiple times to be understood. The book wouldalso benefit from a timeline to summarise majorscientific events, which are not presented inchronological order. Finally, while the plates areinformative they are also quite small, making it difficultto pick out details.

These are minor concerns, though; overall this is anexcellent book exploring both the oldest stars and thelife of a scientist, bursting with information and passion.While not for people who are completely unfamiliar withastronomy, amateur astronomers and aspiring scientistswill only keep on learning from this book.

Osnat Katz

The Cosmic WebAuthor: J. Richard Gott

Publisher: Princeton University Press

Year: 2016ISBN: 9780691157269

Price: £22.95Hardback, 272 pp

Searching for the Oldest Stars:Ancient Relics from the Early

Universe

Author: Anna FrebelPublisher: Princeton University

PressYear: 2015

ISBN: 9780691165066Price: £22.95

Hardback, 320pp


Report for August andSeptember 2016

Another quiet period for thesection, with clear, dark skies in

short supply. Despite this, fourmembers were successful in makingobservations, in all they producednineteen images and two sketches.

Ian Papworth sent in this image ofM76, the “little dumbbell” planetarynebula, which can be found in theconstellation of Perseus. At 3 x 1arcminutes in angular size, andmagnitude +10.1, visual observerswith a 80 mm telescope should see itusing averted vision at around 50xmagnification. Ian also imagedglobular cluster M92 in Hercules,and three more planetary nebulae:M27 – the “dumbbell” in Vulpecula,NGC 7662 – the “blue snowball” inAndromeda, and NGC 6826, – the“Blinking” planetary nebula inCygnus. Ian uses a CelestronNexStar 6SE f6.3 SCT together witha ZWO ASI 120MM camera plus red,

blue and green colour filters.Steve Norrie sent in images of

thirteen deep sky objects; shownhere is NGC 7635 , the “bubble”emission nebula in the constellationof Cassiopeia. The bubble is beingmade by the fierce stellar wind froma hot, massive central star. Steveemploys a ES127 APO CF refractorat focal ratios f7.5 and f5, and anAtik 490 EX one-shot colour camera.Steve's other images were of IC5246, the “cocoon” emission nebulain Cygnus, IC 1805 – the “heart”emission nebula in Cassiopeia, M33spiral galaxy in Triangulum (twoimages), M101 spiral galaxy in Ursamajor, NGC 40 planetary nebula inCepheus, NGC 281, the “pacman”emission nebula in Cassiopeia, NGC6960 and 6992, parts of the “veil”supernova remnant in Cygnus, NGC7023 the “iris” reflection nebula inCepheus, NGC 7317 galaxy inPegasus, and NGC 6888 – the“crescent” emission nebula inCygnus.

David Davies imaged a part of theVeil Nebula, called “Pickering'striangle” (see ‘Showcase’ on page47). The Veil is a large supernovaremnant in the constellation of

Cygnus – so large that it has severalNGC numbers cataloguing distinctparts of the nebula, with theexception of “Pickering's triangle”,which has no assigned number. Thesupernova that created the Veil isthought to have occurred around5,000 years ago. David used an 8”Richey Chretien telescope at f5.6,with a QSI 583 camera and red, blueand green filters.

Michael Kinns used an OrionOptics (UK) 200 mm f6 Newtonianreflector at a magnification of x100to sketch two globular clusters: M2in the constellation of Aquarius, and

M71 Sagitta. On an exceptionallyclear night, Michael noted thatdespite the low elevation of M2,stars of magnitude +13.3 were seenin the telescope field of view. M2 isabout 175 light years in diameter,and is considered to be 13 billionyears old, containing around 150,000stars.

All these images and drawingsmay be seen on the SPA website,www.popastro.com/deepsky/reports,in colour where appropriate.

Dave Finnigan


SECTION REPORTS

A round up of observations, news and notes from the SPA Observing sections (all times UT)

DEEP SKY

Late summer DSOs

▲ M76, the “little dumbbell”, imaged byIan Papworth.

▲ NGC 7635 , the “bubble” emission nebulaimaged by Steve Norrie.

▲ A sketch of M2 in the constellation ofAquarius by Michael Kinns.

Are you aware of the many different ways in which SPAmembers can contribute to the observing sections?

The SPA section directors are happy to help with all aspects of observing. Many sections have their ownobserving forms which are available from the SPA website at www.popoastro.com. Please email yourastronomical notes, drawings or images to the section directors using the contact details on page 46.


Marc Delany took these lunar images from hishome in Barry, South Wales using a Meade-

LS-ACF 6” and a ZWO 178MC camera.

SECTION REPORTS

High summer into early autumnwas an unhappy period for

planetary observation from the UKwith long, light evenings, shortperiods of true darkness and adearth of bright targets to view. Theouter planets, Uranus and Neptunewere certainly on show but these icegiant worlds do not always receivethe attention they deserve withmany visual observers consideringthem too small and lacking inobvious detail to be worth observing.On the other hand the planetaryimaging community has made greatstrides in extracting atmosphericdetail from them over the last coupleof years. It is still true that there islittle point in trying to image suchdistant targets unless the seeingconditions are very steady, as Ifound to my own cost with multipleattempts leading to no worthwhileresult; fortunately others were more

successful as I will report! However Iwill describe the observations sent tome in August and September instrict chronological order, and thatmeans beginning with Venus.

On 12 August, Carl Bowronmanaged to capture Venus in fulldaylight, around 15:36 UT, using a15 cm aperture refractor at F18 anda NexImage planetary camera. Atthat time Venus was just 18 degreesfrom the Sun and I have comparedhis image to the one he took in Julyat an even more impressive, andperhaps slightly risky, 10 degrees ofseparation. Carl is an experiencedsolar imager so is well aware of thedangers of using optical equipmentso close to the Sun and his resultsshow the slight change in phase andgrowth in size of Venus over thistime very clearly.

On 12 August, Venus, Mercury,and Jupiter were all spread out in a

ragged line pointing eastwards,away from the Sun. At 18:18 UT,still in daylight, Simon Kiddmanaged to capture an image ofMercury, some 10 degrees east andat the same elevation as Venus, thatshows bright albedo featurescorrelating with known surface


LUNAR

PLANETARY

Planets imaged during short summer nights

▼ On 12 August, Carl captured thisimage of Venus in full daylight on 12August at 15:36 UT.

◄ LunarcratersPtolemaeusAlphonsusArzachel andRupes Recta.

▲The lunar crater Plato.


features. The image shown hereincludes a simulation made usingthe Winjupos software for the timeof the image and which makes thecorrelation somewhat clearer. Thelow elevation and small apparentsize of Mercury, especially as seenfrom the UK, makes this image anotable achievement, especially asSimon described the seeingconditions at that time as“precarious”.

On 15 August, Dave Tylermanaged to capture a remarkableSaturn image. During what was, ashe described it, the best seeingconditions that he had had in thelast six weeks, he used a CelestronC14 telescope with an ASI 120Mcamera and an ASI AtmosphericDispersion Corrector (ADC). Hecaptured an image showing the fullCassini division, a hint of the Enkedivision in the rings, structure in thebright B ring, a sharp shadow of theplanet falling on the ring systembehind it, and a pale yellowequatorial band with a soft pinktemperate region and a pale greenband surrounding the north pole.Please note this was an image takenwith the planet at barely 17 degreesof elevation above the horizon.

Shortly afterwards, on 30 August,Martin Lewis managed to capturedetail on the planet of Neptune. Heuses a Dobsonian telescope on atilting platform that allows thisequipment to follow a target as if itwas equatorially mounted and, onthis occasion, he used an ASI224MCcolour camera fitted with a Baader610 nm long-pass filter; one thatonly allows deep-red and infraredlight to reach the sensor. The imageshows a clover-leaf shaped collection

of clouds in the south polar regionsof Neptune that has also beentracked by a few other amateurs andprofessionals. Images like this adddata-points for those studying theatmospheres of these frigid outerworlds and therefore add directly toour understanding of them.

Steve Norrie managed to “GoTo”directly to Neptune and studied itsdisc. This brings me to takingplanetary images with smalleraperture telescopes. Steve Andersonemailed to ask for more details ofhow Robin Scagill obtained hisimages of Mars and Saturn using a5” aperture Newtonian telescope ashe thought this might inspire otherswith similar equipment to try outimaging. Robin used an ASI120MCone-shot-colour camera, which is oneof the many readily availableplanetary imaging video cameras,combined with a laptop and freeimage-sorting and stacking softwaresuch as Autostakert or Registax toproduce his images.

Suffice to say that the brighter and

larger planetary targets are easilyimaged with all apertures oftelescopes and scientifically usefulresults can be obtained withouthaving to own the largest “lightbucket” available. Ultimately thehighest resolution images will comefrom the largest apertures but onlywhen our back yard seeingconditions match the theoreticalresolutions available; which is rarelyin the UK. If you don't own a largeaperture telescope, please don't beput off from attempting planetaryimaging as you may be surprised bythe results you can obtain.

Finally I will mention theplanetary globes created by EddieCarpenter. He sent me some imagesof his home-made globes that may beof interest to others. I was luckyenough to see the collection ofplanetary globes owned by SirPatrick Moore and always wantedsomething similar. A few such globesare available for sale over theinternet, particularly of Mars, but atrather high prices. Eddie decided tomake a set of his own usingrepainted classroom style globes andhe painted Mars according to hisown observations. His widecollection of other globes evenincludes Enceladus, Titan, Pluto andCharon, taken from availableimages, and I was surprised to findfrom him that there are evenaccurate inflatable globes of Marsavailable from Japan.

As always, thank you for all yourcomments and observations and Ihope you all have clear skies duringthe autumn and winter viewingseason.

Alan Clitherow


SECTION REPORTS

▲ Eddie Carpenter’s home-made globe of Mars.

▲ Martin Lewis captured detailon the planet of Neptune on 30 August.

▲ Dave Tyler’s image of Saturn taken on 15August.

▲ Simon Kidd’s image of Mercury showsbright albedo features correlating withknown surface features, which can be seenin the Winjupos simulation on the right.


SECTION REPORTS

Six observers: Don Matthews, Jonathan Shanklin,Matthew Barrett, Tracie Heywood, Graham Taylor

and Brendan Shaw submitted observations for Augustand September, allowing us to keep track of the stars onthe section’s programme.

The highlight of these months was the Septembermaximum of the Mira-type variable Chi Cygni. Recentmaxima had differed markedly in their brightness. ChiCygni had reached mag. +3.8 in May 2013 and mag.+4.3 in August 2015, but had only managed mag. +6.5 inJune 2014. Observations by section members revealedthis latest maximum to be more “average”, peaking ataround mag. +4.9.

The late summer saw another Mira-type variable, RUrsae Majoris reach its annual peak. Observationsshowed that the peak brightness was about mag. +7.0,

slightly brighter than the average maximum. The peakseems to have occurred in late August, slightly earlierthan predicted.

Observing using binoculars means that only themaxima of Mira-type variables can be seen. It is


Chi Cygni at maximum

VARIABLE STAR

▲ Light curve for S Ursae Majoris between March and August 2016.

AURORA AND NLC

Aurora activityCoronal hole impacts occurred on 23-24 and 30-31August. The latter was the result of three coronal holeswhich then seemed to join up and occupy the top third ofthe Sun, and this dominated the first and last weeks ofSeptember. The strongest of the first week was on 2-3when it was visible in Whitby North Yorks. The nextsession started on 25-26 when it coincided with theEarth crossing the current sheet and this was thestrongest night and seen in Saltfleetby, Lincs by PaulCotton. The displays continued on a nightly basis until 5October but were all limited to Scotland. An interestingphenomenon was observed on 28-29 September when abeam was seen to the west of the main display. This isknown as a proton arc and they seem to last about 20mins (see the image in ‘Showcase’ on page 47). Anysightings of this or further information would beappreciated as there is still a lot to learn about it.NLCThe NLC season has been an odd one with plentyavailable, but bad weather causing very few sightingsuntil July, when the weather improved and gavemultiple sightings on the 1-2, 3-4 and 5-6 with it visiblein southern England. A second series of sightingsoccurred from the 8th to the 13th but mostly fromScotland. Another batch was on the 22-23 after which,the NLC started to retreat and by August it was down tothe odd one or two. My thanks to all those who sent inreports and help to understand this phenomenon.

Useful websitesed-co.net/nlcnet/ is run by Tom McEwan and has all thesightings of NLC from across Europe.www.spaceweather.com is an excellent site for beingforewarned of any aurora.www.solarham.net is a good site for anything Sun-related and also gives a prediction on activity that caneffect Earth.

Sandra Brantingham

The last sightings of the season for NLC (noctilucent cloud) occurred on 13 August 2016. The Sun is getting veryquiet very fast and the 11 year cycle seems to be coming to an end with several days of no sunspots happening

already. This means that the majority of aurora will come from coronal holes. Having said that there has been amassive coronal hole covering the top third of the Sun which has supplied aurora for August and September.

▲ Aurora was taken on 25 September 2016 by Paul Cotton fromSaltfleetby, Lincs. The faint band seen spreading across the image justabove the treeline is the aurora which was glowing green.


interesting to also know how they are behaving atfainter magnitudes. Observations by Don Matthews arehelping to answer this question. S Ursae Majoris was atmaximum during spring 2016 but earlier in 2016 and inthe summer it was below binocular visibility. Don’sobservations have extended the light curve (shownbottom right of page 38) down to fainter magnitudes,during both the rise towards maximum and the fadefrom it.

The Cepheid variable Eta Aquilae was monitoredduring 2015 and 2016 by Matthew Barrett and GrahamTaylor. Cepheid variables show highly predictablechanges in their brightness, with those of Eta Aquilaerepeating every 7.18 days. In the light curv below, allobservations have been combined to show one and a halfof these cycles of variation. Due to Eta Aquilae’srelatively small brightness range, there is inevitablysome scatter, but the general pattern of a steep rise tomaximum (at phase 0) followed by a slower fade backdown to minimum can be clearly seen.

As mentioned in the Nov-Dec issue, R CoronaeBorealis had been well below binocular visibility sinceJune 2015. Observations by Don Matthews, along withthose published elsewhere, show it brightening by amagnitude per month during the summer of 2016 andreaching mag. +10.8 by the start of October. If this trendhas continued, it will be visible in binoculars by now(although only observable in the morning sky). On theother hand, the brightening could have slowed, pausedor reversed. R CrB Is just that unpredictable!

Two Mira-type variables will be of particular interestduring January and February – for very differentreasons.

It is quite a few years since we have been able to seeMira (omicron Ceti) at maximum. Recent maxima havetaken place during the spring months – when Cetus isnot visible in the night sky. The 2017 maximum will bemore favourably timed, being predicted to occur at theend of February. By this time, of course, Cetus will begetting low in the evening sky, so it will be a case ofgoing out to observe it as soon as the sky is dark. Priorto this, we will be able to see Mira brightening towardsmaximum. Predicting the changes of Mira-typevariables is always tricky, but it is likely that Mira will

be around the fainter limit of the finder chart above atthe start of January and should then brighten quiterapidly over the following weeks. From fairly lightpolluted skies, not much is usually visible with thenaked eye in Cetus, which can make locating Mira a bittricky. However, a good guide to the location of Mira canbe to follow the direction in which the “V” shape of theHyades points.

In the case of T Cephei, we will be interested to see theextent to which it stops(!) varying (for a while). ThisMira-type variable usually pauses briefly around mag.+8.0 during the rise to maximum. This pause usuallylasts for a week or two, but the 2015 and 2016 pauseswere unusually prolonged. The 2015 pause lasted forabout two months, and the 2016 pause (as shown in thelight curve in the 2015 Nov-Dec issue of PopularAstronomy) lasted for around three months. We don’tknow whether another long pause will occur in early2017. We will just have to go out and have a look forourselves. You can do so by using the finder chart belowin which comparison stars are labelled with theirmagnitudes (decimal point omitted, so “81” representsmag. +8.1).

Tracie Heywood


SECTION REPORTS

▲ Finder chart (approx 8 deg x 6 deg) showing the location of T Cephei and suitable comparison stars.

▲ Finder chart showing the location of Mira and stars with which tocompare its brightness.

▲ Finder chart showing the location of Mira and stars with which tocompare its brightness.


SECTION REPORTS

The predictions confidently said that there was a goodchance of seeing higher than usual activity from the

Perseid meteor shower from the UK at some time during thenight of 11-12 August. Inevitably, some people on social mediagot carried away and made wild predictions of storm levelPerseid activity. However, none of the reliable sources werepredicting that observed rates would exceed anything morethan around double normal levels. A meteor storm wascertainly out of the question.

Importantly, would the weather cooperate, or would most ofthe UK be clouded out?

Visual meteor watchesNote: limiting magnitude (LM) is a measure of sky clarity. It isdefined as the magnitude of the faintest star you can just seewith averted vision while meteor observing.

8-9 AugustMost of the nights during the build up to Perseid maximumwere cloudy. However, clear skies were more widespreadduring the night of 8-9 August. Tracie Heywood (Leek) madeuse of a spell of mostly clear skies between 00:37 UT and 02:37UT (2 hours, LM +5.5 to +5.4) to see 26 meteors, 13 of thembeing Perseids. Her brightest meteor was a yellow mag. -1Perseid at 01:35 UT, which left a train that persisted for 0.5seconds. Graham Winstanley (Bassingham, Lincs) saw fivemeteors, including two Perseids, between 23:36 and 00:40 UT(LM +5.5). Tom Banks (Comberbatch, Cheshire) saw eightPerseids and eight sporadics between 01:25 and 03:40 UT (LM+4.9).

Perseid maximum night 11-12 AugustA Perseid outburst did indeed occur near 23:00 UT during thisnight. Unfortunately, much of the UK was clouded out. Theclearest skies were in southern England but there were alsopartially clear skies for some observers in eastern areas.

David Scanlan (Romsey, Hants) observed between 20:50 and00:20 UT (3h30m, LM +5.0) and got a good view of theenhanced activity, seeing 51 Perseids and 7 sporadics. Of thePerseids, 26 were seen between 23:04 and 23:40 UT, thebrightest being a long mag. -6 Perseid at 23:12 UT in Cygnusthat fragmented and left a train which persisted for nineseconds.

Ken Meadows (High Wycombe) observed from 21:36 UT on(LM +5.0), seeing 10 Perseids and one sporadic before cloudintervened at 22:38 UT (just before the enhanced activity seenelsewhere). Later, from approx 01:20 UT onwards, he saw 28Perseids and 7 sporadics (LM +5.0 to +5.3), before theapproaching dawn ended his observations at 03:24 UT. Hishighlight was a mag. -5 Perseid seen in Cepheus at 03:11 UT.

Mike Feist reported carrying out a series of short watchesbetween 00:20 and 03:10 UT in skies in which the DoubleCluster was visible along with some detail in the CygnusMilky Way. He noted a good number of bright trainedPerseids including a particularly bright one in Auriga near the“Kids” which left a long-lasting train that he was able to followfor some time using his 8x40 monocular as it twisted andfinally faded out.

Increasing cloud hindered Graham Winstanley’sobservations but, observing from Bishop Stortford, he saw fourPerseids between 22:07 and 22:36 UT (LM +4.5).

Alastair McBeath (Morpeth) had a lot of cloud interferenceand rather windy conditions, but in a series of short watchesbetween 23:38 and 01:37 UT, totalling approx 1.05 hours (LM+6.1 to +6.2), he recorded 47 meteors, 43 of which werePerseids. He also reports seeing a further 24 meteors (21Perseids, 3 sporadics) during 51 minutes of casual observingduring spells with more cloud cover.

12-13 AugustDespite the “normal” Perseid maximum having occurredduring the early afternoon of 12 August, Perseid rates werestill likely to be good during this night, albeit with the Moonanother day closer to Full. Fewer observers had clear skies butseveral did report results.

Graham Winstanley saw 15 Perseids and one sporadicbetween 21:25 and 22:30 UT (LM +4.7). Ken Meadows hadsevere cloud interference but saw five Perseids in just over anhour. Michael Kinns (Sandwich, Kent) observed between 21:50and 23:30 UT, seeing 16 Perseids (LM +5), ranging inbrightness from mag. 0 to mag. +4. Graham Taylor (BroughtyFerry, near Dundee) observed between 22:22 and 23:24 UT,seeing 11 Perseids (LM +4.0).

14-15 AugustTom Banks reported seeing eight Perseids and two sporadics

between 23:00 and 01:00 UT (LM +4.7) and then saw another11 Perseids between 01:12 and 02:40 UT (LM +4.7).

Imaging11-12 AugustCloudy skies proved a challenge for many imagers, but somefared much better.

Alex Pratt (Leeds), for example, only managed to image 11Perseids, whereas other imagers in the NEMETODE groupwith clear skies captured hundreds of Perseid images.

Richard Fleet (Wilcot, Hants) posted many images of brightPerseids to the live feed on the UKMON website. Two wereparticularly noteworthy. One was a bright fireball at 23:12 UT(the same one as seen visually by David Scanlan) that wasimaged by cameras pointing in two different directions (SWand SE). The other was a bright fireball, shown in the imagebelow, that appeared low in the sky at 03:46 UT during themorning twilight.


Clouds did not stop Perseid observations

METEOR

▼ Richard Fleet’s image of a Perseid fireball at 03:46 UT in themorning twilight of 12 August 2016.


12-13 AugustCloud was more widespread than on the previous night, with

a weather front moving southwards across the UK, but someobservers did get some clear sky.

Bill Ward (Kilwinning) had better luck than on the previousnight – but only just – as his observations were sooninterrupted by cloud and rain. Bill commented “One 15 minutewindow is all it takes...” and he was amply rewarded with animage containing two Perseids, followed within a minute byhis capture of the spectrum of a bright Perseid in which aconsiderable amount of detail was visible.

Paul Sutherland reported capturing images of 19 Perseidsand two sporadics using a Fujifilm X-M1 camera fitted with aSamyang 12 mm/f2 lens, working at ISO 1600. Each frame wasexposed for 10-15 seconds only. Paul noted that a few meteorsfinished with a flare-up and one left a persistent train thatwas recorded in the two following frames.

Meteor spectraDuring his 15 minute clear spell on 12-13 August, Bill Wardcaptured a Perseid spectrum. As often happens, only part ofthe spectrum, in this case the red and near-infrared, fellwithin the camera's field of view. Bill was particularly pleasedwith the level of detail in this spectrum. He compared theatmospheric emission lines (O, O2 , N, N2 ) in his spectrum withthose recorded in a detailed spectrum by the (rather moreexpensive) VLT while observing a distant supernova in 2002.The comparison is shown in the diagram below. The VLTspectrum sections are in the lower two boxes. Modelling by theastronomers indicated these lines fitted the profile of anemission at a temperature of 4200K at a height of 95 km in ouratmosphere. Bill noted “a cool aspect is the 'height' of the linesin the regions marked. Comparing the various scalings showsa very good ratio relation. So it would suggest that my realspectrum matches the modelling quite well. 4200K it is!”

Radio observationsBill Ward also monitored Perseid activity using radio methodsand recorded many of the unusual (and not yet understood)“epsilon” type echoes along with some very long durationechoes.

The graph (at top right) has been generated from Bill'scolorgramme plot on the rmob website. Each bar represents

the meteor echo count during a one hourinterval. A distinct isolated peak can be seen

in the interval that starts at 23:00 UT on 11 August. This tiesin with the enhanced Perseid activity reported by those visualobservers who had clear skies.

Also obvious in the graph is a daily variation in counts withmaxima near 05:00 UT and minima near 17:00 UT each day.Although observed meteor rates do routinely show a 24 hourlyrise and fall, the hour to hour changes seen here are alsoinfluenced by the changing position of the Perseid (and other)

radiants in the sky relative to the GRAVES transmitter andBill's receiver and also, of course, by the changing activity levelof the Perseids themselves. Nevertheless, it can be clearly seenthat overall rates were higher during 11-12 August thanduring the preceding and following nights.

Two notable fireballs17 August 01:05 UTThis fireball was seen through a window by Steven Gray(Winchburgh, near Edinburgh). Visual reports of this fireballwere also submitted by several witnesses across the north ofEngland. A check with the NEMETODE video camera networkrevealed that cameras in Ayrshire and the Isle of Man hadcaptured images of the fireball’s path. Bill Ward had alsocaptured an image of part of its spectrum. Triangulationshowed the fireball’s trajectory to have been over the England-Scotland border and heading out over the North Sea in aroughly NE direction.

23 September 22:34 UTThis impressive fireball was seen by many observers acrossthe south of the UK and also by observers in Belgium, theNetherlands and northern France.

Richard Fleet captured the image below via his south-eastfacing camera.

Many visual reports were received by the Meteor section. ForKarl Leach (Chastleton, Gloucs) the fireball was in his SE sky.He reported “A light green trail finishing in a really brightflash. The flash lit up the whole sky briefly.” Adrian Bradley(London) saw the fireball in a direction between ESE and SEand gave this description “It looked like a molten line of lightas it went through the sky. It ended in a bigger flash”. EmmaLaflin (Cambridge) saw the fireball in her southern sky, givingthis description “It was coming straight down and as it fell thelight got brighter and flashed a blue/green/red/orange colour asit got close to the ground. It then disappeared.”Triangulation of images showed the fireball to have beenlocated over the English Channel, to the south of the Sussexcoast, and heading in a SSE direction.

Tracie Heywood


SECTION REPORTS

◄ The intensityplot of a meteorspectrumcaptured by BillWard at 22:34 UTon 12 August2016, along witha omparison ofatmospheric linesrecorded by Billand by an oldVLT spectrum.

▲ A graph showing the hourly meteor echo counts recorded by BillWard during 11-13 August 2016.

► RichardFleet’s imageof the brightflaring fireballat 22:34 UT on23 September2016.


THE SOCIETY PAGESReports, news and notes from theSociety for Popular Astronomy

Over 200 people attended theSPA’s “out of town” meeting at

Jodrell Bank on 17 September 2016.It turned out to be a fabulous day inall respects: the weather was kindwith wall-to-wall sunshine, the talkswere excellent, and the catering wasmuch appreciated.

Nestled in the shadow of thefabulous Lovell Telescope, theparticipants were treated to a fullday of activities. The opening talk onthe history of Jodrell Bank was givenby SPA president Professor TimO’Brien. This was followed byProfessor Rob Jeffries from KeeleUniversity who described thedetection of gravitational waves inthe context of Einstein’s generaltheory of relativity in terms thatwere readily understandable by theaudience.

Due to the large attendance,lunchtime was split into two sessionswith Professor Ian Morrison fromJodrell giving his talk on the searchfor life beyond the Earth twice so

that everyone could attend. Afterlunch, Professor Lucie Green fromUCL described the latest spectacularspace observations of the Sun in atalk entitled 15 Million Degrees:Journey to the Centre of the Sun,which is also the title of her recentlypublished book. Finally, ProfessorMike Bode from Liverpool JohnMoores University gave anentertaining look at the veryimportant role that robotic telescopesplay in astronomical observing.

During the refreshment breaksthere was opportunity to sample themerchandising stalls and everyoneappeared to have a great time, withsome people having travelled from asfar as South Wales and Cornwall toattend. The overwhelming messagefrom those present was that an “outof town” event, well away fromLondon, needs to become a fixture inthe SPA programme.

Ian Robson


The SPA at Jodrell Bank

Saturday 28 January 2017, 2 pm. Khalili Lecture Theatre, SOAS, London. The SPA Annual GeneralMeeting is followed by the main speaker Dr Jonathan Pritchard of the Astrophysics Group, Imperial CollegeLondon, on The Cosmic Dawn and the first galaxies. Observations of the cosmic microwave background and thedistribution of galaxies reveal a universe that develops from early simplicity to eventually form galaxies like ourMilky Way. Somewhere in this cosmic history, the very first galaxies form, ushering in a cosmic dawn as starlightilluminates the universe for the first time. This period of cosmic dawn has yet to be observed directly, since thesegalaxies are too faint to see with even the Hubble Space Telescope, and so represents one of the “here be dragons” in

our picture of the cosmos. In this talk,Jonathan will discuss something of thelife and death of the first stars andgalaxies and describe current efforts tolearn about the cosmic dawn with a newgeneration of FM radio telescopes, suchas LOFAR and the SKA. Following thebreak, Robin Scagell will look at someof the highlights in the sky for the nextthree months. Then TonySizer intrigues us with a talkentitled The Stars, Like Dust. IsaacAsimov's 1950s SF classic? Come alongand find out!

Please note: Regular SPA London meetings startat 2pm sharp and end at 5pm.

SPAmeetings

SPA meetings are usually held on the last Saturday of January, April, July and October at theSchool of Oriental and African Studies (SOAS), University of London, Thornhaugh St, RussellSquare, London, WC1H 0XG. Meetings start at 2pm and last until 5pm, including a break forrefreshments. Members and their friends are welcome, entry is free and there’s always a friendlyatmosphere. Members should bring their membership card or a copy of Popular Astronomy.

▼ From left to right: Rob Jeffreies, Lucie Green and Mike Bode. Credit Margaret Penston.


René Breton introduced his talk by reminding us thata pulsar is a particular type of neutron star. These

are the collapsed remains of massive stars only about 10km across and with a mass about 1.4 times that of theSun, but with an enormous magnetic field – 1012 gauss,which is a trillion times that which we experience atEarth’s surface. Pulsars get their name from the beamingof radio waves from their magnetic poles, which wereceive as repeated pulses in the same way that we seeflashes from a beam of light sweeping around alighthouse.

They spin at rates from several seconds down tomilliseconds – the record being a staggering 1.39 ms perspin. Most of those with very short periods – of the orderof milliseconds rather than seconds – turn out to be binarypulsars, where both stars in a binary system have turnedinto a neutron star at the end of their lives. In onecelebrated case, known as the double pulsar, both starsare pulsars.

Pulsars provide an ideal environment to test Einstein’stheories of relativity. Whereas the orbit of Mercurychanges by 43 arcseconds a century as a result of thedistortion of space-time, predicted by the General Theoryof Relativity, that of the double pulsar changes by 17º ayear. René showed a graphic video of how a doughnut-shaped disc around one component of the double pulsaraffects the signal from the other.

Another use of radio pulsars to test relativity lies indetecting gravitational waves from the merger ofsupermassive black holes – if such events occur. At Jodrellthey are monitoring pulsars in different directions in thesky in the hope of picking up changes in their timingresulting from the passage of such a gravitational wave.

After the break, Robin Scagell explained why Mars isactually getting higher in our evening sky many monthsafter its opposition last May, and suggested that peopleshould keep a watch for aurorae even though the Sun iswell past its maximum of activity.

Then Alice Sheppard of UCL’s Extreme Citizen ScienceProject looked at the various ways in which you can helpmake astronomical discoveries from the comfort of yourhome. Back in the 19th century much science was carriedout by amateurs. Now all you need is a computer and a

connection to the internet. For example, you can try Globeat Night, a citizen science dark-skies project, Having putin your location, you’ll see a screen which allows you tomeasure your sky brightness by choosing the numbers ofstars you can see in a particular part of the sky. Anothersite, Aurorasaurus, analyses Twitter feeds to work outwhere the northern lights are currently being seen.

If you fancy a bit of meteor spotting you can go to thezooniverse.org site and log on to radio meteors. Computersare not much good at picking out radio meteors from thegraphs displayed, but you could help to pick out a newradio meteor shower.

For lunar observers there’s cosmoquest.org’s MoonMapper program. It shows photos from the LunarReconnaissance Orbiter and invites you to help pick outthe actual craters. Or you can do the same using photos ofMercury or Mars. Junocam.org gives you the opportunityto process photos taken of Jupiter.

Alice’s favourite site is definitely galaxyzoo.org. One ofthe successes of the Galaxy Zoo was the discovery of acompletely new class of galaxies, known as “green pea”galaxies because they appear round and green.Participants discuss the data among themselves, and forma community which is separate from the traditionalacademic community of astronomers.

You can view the full talks on the SPA website,www.popastro.com, by going to the Meeting Videos tab.


Einstein’s Relativity: tested tothe limit with pulsars

THE SOCIETY PAGESRobin Scagell reports onthe SPA meeting of 30 October 2016.

▲ René Breton (left) and Alice Sheppard (right). Credit: Margaret Penston.

Jack Meadows (1934–2016)

Prof. A J Meadows became the Society’s president in January1975. He was only the second of our presidents to be drawn from

the world of professional astronomy, following Prof. Ian Roxburgh, andas with all our subsequent presidents, he had to adjust to the world ofamateur astronomy. However, Jack fitted in perfectly, as his interest inastronomy came from a love of the subject and its background. He wasProfessor of Astronomy and History of Science, so he was as at homediscussing the constellations as the latest results from the space probeswhich were starting to reveal the true natures of the planets.

He brought wisdom to the Council table, but always with humour,and was a true friend to the society.

▲ Jack Meadows making a point with some vigourat a meeting at Alliance Hall, Westminster. Credit: Robin Scagell.


Sky DiaryA summary of the main sky events, January to February 2017 (UT times)

Occultation notesFifteen stars are occulted over this two month period but

not everyone will see them as three of the events aregrazes. The stars themselves are not particularly bright,ranging in magnitude from +4.3 to +6.0.

On the evening of 5 February, five stars are occulted whenthe Moon is moving through the constellation of Taurus, four ofwhich, location dependant, are occulted over a 45 minuteperiod.

A few of the occultations will be more challenging to observedue to the phase of the Moon at the time. ZC 1238, on 13January, and 49 Leonis, on 12 February, have to contend witha 99% illuminated Moon, whereas 18 Leonis on 11 February isocculted by a Moon just six hours past full.

The first of the three grazes involves the +5.8 magnitude star13 Librae on 21 January. The graze path passes through


Moon phases

Apsides

Occultations ReappearanceDisappearance

Dark limb

Bright limbThe position angle (PA) of the

occultations given below is measured anticlockwise from thenorthpoint of the Moon’s disc (usethe Moon’s north pole as a guide).

270°

180°

0°

90°

These are the only occultations for this period, based on the following criteria: Mag: Visual magnitude. Phase: (R)eappearance, (D)isappearanceor (G)raze at (D)ark or (B)right lunar limb. Alt: Altitude. The Moon’s height. Az: The angular position along the horizon measured clockwise fromtrue north (through E, S, W back to N). PA: Position Angle, measured anticlockwise from the direction of the celestial North Pole. This listingshows lunar occultations of stars brighter than mag +6, observable with small telescopes in a sky dark enough to be seen without difficulty. Fordata specific to your own locality or details of fainter occultations, contact Occultation Section Director Mell Jeffery (address on p46).

Data for Greenwich Data for EdinburghDate Name ZC Mag Phase Time PA⁰ Alt⁰ Az⁰ Time PA⁰ Alt⁰ Az⁰09-Jan 741 5.5 DD 22h 52m 58 53 210 22h 52m 41 50 20311-Jan 944 5.9 DD 05h 34m 151 8 289 05h 24m 142 12 28413-Jan 1238 6 RD 04h 32m 304 33 254 04h 22m 311 35 24621-Jan 13 Librae 2128 5.8 RD 03h 06m 351 10 124 APPULSE

02-Feb nu Piscium 249 4.4 DD 19h 02m 62 36 223 19h 00m 47 34 21603-Feb mu Ceti 405 4.3 DD 23h 34m 97 10 274 23h 27m 85 13 26905-Feb 80 Tauri 675 5.6 DD APPULSE 18h 44m 138 48 16005-Feb NSV 01627 677 4.8 DD 19h 10m 26 55 173 APPULSE05-Feb 81 Tauri, NSV 16040 678 5.5 DD 19h 21m 168 54 183 18h 56m 129 49 16405-Feb 85 Tauri 682 6 DD 19h 37m 121 54 184 19h 28m 104 50 17505-Feb 89 Tauri, NSV 16124 699 5.8 DD 23h 06m 141 35 250 22h 50m 123 37 24007-Feb 130 Tauri 878 5.5 DD 03h 04m 118 10 286 02h 56m 110 14 28108-Feb 74 Geminorum, NSV 1158 5 DD 23h 00m 58 55 195 23h 01m 40 51 190

367111-Feb 18 Leonis 1439 5.7 RD 06h 08m 306 11 275 06h 00m 310 14 27012-Feb 49 Leonis, TX Leonis 1550 5.6 RD 03h 41m 314 37 231 03h 30m 319 36 222

Last quarter New First quarter Full19 Jan,22:14 28 Jan, 00:07 05 Jan, 19:47 12 Jan, 11:3418 Feb,19:33 26 Feb, 14:58 04 Feb, 04:19 11 Feb, 00:33

Date Apsis Dist (km) Size10 Jan, 06h Perigee 363,238 32’ 54”22 Jan, 00h Apogee 404,914 29’ 31”

Date Apsis Dist (km) Size06 Feb, 14h Perigee 368,816 32’ 24”18 Feb, 21h Apogee 404,376 29’ 33”

◄ 5 Feb 80 Tauri graze path.

► 21 Jan 13 Librae

graze path

Colonsay and Jura, to the north of Kilmarnock, cross countryand out to the east coast just south of Seaham. To the south ofthis graze line an occultation can be observed.

There are then two graze events on 5 February bothoccurring during the 45 minute period where five stars areocculted. 80 Tauri is occulted first with the graze path startingat the Welsh coast and inland south of Llanllyfri, travellingthrough Manchester, north of Beverley and out to the eastcoast near Hornsea. North of this graze line an occultationtakes place.

The second event on 5 February is that of the +4.8 magnitudestar NSV 0162 (ZC 677). The graze path for this event starts onthe west coast of Scotland to the south of Ballantrae, then goesthrough Moffat and to the east coast near Belford. South of thegraze line and occultation can be observed.

Mell Jeffery


PlanetsMercury has its greatest morning (western) elongation fromthe Sun on 19 January, when it rises 24 degrees ahead of theSun. From UK latitudes, it will be very low in the sky withatmospheric extinction effects making the planet hard to seenaked eye. Between 9 and 19 January at 07:15 UT it may beseen in the SE at around 5 degrees of elevation, with Saturn alittle further south and slightly higher acting as a pointer.Mercury will show a steadily increasing illuminated phasefrom around 35% to over 50% in this period, and it willbrighten noticeably from a magnitude of +1.2 to +0.7.

Venus also reaches greatest elongation in the period but inthe evening (eastern elongation) of 12 January. On that dateVenus will be separated by 47 degrees from the Sun and willset 4 hours and 25 minutes after sunset for mid UK latitudes,making it visible throughout twilight and into trueastronomical darkness. Throughout the period, Venusdominates the south-western sky, shining at a magnitude of -4.3 on 1 January, reaching a dazzling -4.6 on 18 February,fading only very slightly by the end of the month. The visiblephase changes considerably falling from 56% illuminated on 1January, to 50% close to greatest elongation, decreasingsteadily to 40% by early February, and then just 17% by theend of the month. In the same period the visible size will growfrom 22 to nearly 47 arcseconds.

The exact moment when the planet appears 50% illuminatedshould occur on the day of greatest elongation; however, thisoften proves not to be the case. Named the Schröter Effectafter its discoverer, Johann Schröter, Venus appears to reach50% phase a few days early with evening (eastern) elongationsand slightly late with morning (western) elongations.

Mars is now rather distant and small but it can still beobserved in the western sky after sunset throughout theperiod. In early January look for it after 17:15 UT as the skydarkens, in the SSW around 25 degrees above the horizon formid UK latitudes. On the last day of January, it forms a tightequilateral triangle with the Moon and Venus and on 27

Sky Diary

Variable star notesEclipsing variables: RZ Cassiopeiae can be seen in eclipseduring the evenings of 3, 9, 15 and 21 January, with the firsteclipse being centred near 19:30 UT and each successiveeclipse in the sequence occurring approximately 35 minutesearlier. Another series of evening eclipses occurs on 16, 22 and28 January, and 3, 9, 15, 21 and 27 February, with the 16January eclipse being centred near 23:00 UT and the last ataround 19:00 UT. Eclipses last for just over four hours.

Eclipses of U Cephei are now becoming more favourable. Onewill be centred near 23:00 UT on 3 January and successiveeclipses will occur at intervals of five nights, with each eclipsebeing centred 20 minutes earlier in the night and the 27February eclipse being centred near 19:30 UT. Eclipses last forapproximately nine hours.

The most favourable eclipses of Algol (beta Persei) will becentred near the following times (UT) in January: 23:25 on the13th, 20:15 on the 16th, and 17:05 on the 19th. In February

the times are 22:00 on the 5th, 18:45 on the 8th, and 20:30 onthe 28th. Eclipses last for nearly ten hours.

Mira-type variables: Having passed through its 9thmagnitude minimum in early November, Mira (omicron Ceti)will be brightening rapidly towards its 2017 maximum, whichis predicted to occur around the end of February. This will bethe first opportunity to see Mira at maximum for several yearsas recent maxima have occurred with Mira close to conjunctionwith the Sun. T Cephei may be brightening towards its Maymaximum during January and February – or it might pausefor weeks near mag. +8.0 – it showed such pauses on the wayto its 2015 and 2016 maxima. R Trianguli will be visible inbinoculars during January as it fades from its Decembermaximum.

Finder charts for these and other variable stars on the SPAVSS programme can be found by clicking on the name of thestar in the section’s programme listing:www.popastro.com/variablestar/observingprogramme/index.php Tracie Heywood


February it can be in the SWS, still some 25 degrees up at18:50 UT, less than 1 degree NNE of Uranus. Its brightnessvaries slightly in the period falling from magnitude +0.9 inearly January to +1.3 in late February and it falls below 5arcseconds in apparent size mid-period making detailedobservation very difficult after this.

Jupiter is an early riser. On 1 January it rises in the ESE at01:20 UT and reaches an elevation of 30 degrees, transitingdue south at 06:45 UT, still in astronomical twilight. By 1February it transits at 04:50 UT and at the end of the monthat 03:00 UT, still at 30 degrees of elevation. Throughout theperiod Jupiter is close to Spica in Virgo, although Jupitershines noticeably brighter than its companion at magnitude -2.3. Jupiter’s apparent size grows from 35 to 42 arcseconds inthe period will be a wonderful target for detailed observationin the steady morning air.

In early January Saturn rises in the SE around 06:50 UT formid-UK latitudes. At the same time in early February it is 10degrees up in the SSE and by month’s end it gains nearly 15degrees an hour earlier; Saturn will be better placed forobservation in early springtime.

As full darkness falls on New Year’s day, Uranus can befound nearly due south at an elevation above 45 degreesagainst the background stars of Pisces. On the edge of nakedeye visibility at magnitude +5.97 this massive but distant icegiant planet will show a diminutive blue-green disc around 3arcseconds across; nonetheless well-equipped imagers will beable to catch some shading and banding in its frigidatmosphere. Uranus will be observable throughout the periodbut by the end of February will be subsiding into the westernsky as darkness falls; catch it while you can.

Neptune is coming to the end of its period of observability buton 1 January it can be found very close to Mars, less than athird of a degree south and west as darkness falls. On Friday,13 January it will be found a similar distance from Venus.Watch the press for suitably silly comments from astrologers!

Alan Clitherow

Meteor notesJanuary: The 2017 Quadrantids are quite well placed withrespect to the Moon. Unfortunately, the narrow maximum ispredicted to occur during the early afternoon of 3 January. Bythe time that it gets dark, Quadrantid rates will have droppedsomewhat and the radiant will be getting low in the sky.Nevertheless, some Quadrantid activity should still be seen,with the best observed rates during the early evening of 3

January and (if you leave your warm bed!) during that day’spre-dawn hours.

After the Quadrantids, it’s rather quiet for meteor activity.Background meteor rates are low early in the year but, if youare lucky, you might still spot a fireball. If you do see one, letus know via our report formwww.popastro.com/meteor/fireballs/ reportform/index.php

Tracie Heywood


Patron: Professor Sir Arnold Wolfendale, FRS, 14th Astronomer Royal

Society for Popular Astronomywww.popastro.com

President: Professor Tim O’BrienJodrell Bank Observatory, Lower Withington, Macclesfield SK11 9DL [email protected]

Vice Presidents: Prof Ian Robson / Robin Scagell [email protected]


Observing Section DirectorsOfficersSecretaryGuy Fennimore36 FairwayKeyworthNottinghamNG12 5DU [email protected]

Acting MembershipSecretary—enrolments,renewals and changes ofaddressBarry Turvey36 FairwayKeyworthNottinghamNG12 [email protected]

TreasurerHelen Walker38 Edwin RoadDidcotOX11 [email protected]

WebmastersRobin Scagell and Paul [email protected]

Popular Astronomy EditorAmanda [email protected]

Editorial TeamAmy TyndallJo Barstow Dwane Doyle

Magazine LayoutMandy Bailey

Publicity OfficerMegan [email protected]

SPA Council MembersAmanda DoyleIan MorisonMargaret PenstonPaul SutherlandBarry Turvey

Weekend Course OrganiserGuy Fennimore36 FairwayKeyworthNottinghamNG12 [email protected]

Aurora/NLC Sandra Brantingham, Trevona, Glenbarry, Banff, AB45 [email protected]

Comet Stuart Atkinson, Flat 4, Garnett Croft Yard, 138 Highgate, Kendal LA9 [email protected]

Deep Sky David Finnigan, 33 Wythall Road, Huntlands, Halesowen, B63 [email protected]

Lunar Graham Sparrow, 73 Bunwell Street, Bunwell, Norwich, Norfolk NR16 1AB(Acting Dir.) [email protected]

Meteor Tracie Heywood, 20 Hillside Drive, Leek, ST13 [email protected]

Occultation Mell Jeffery, 11 Chestnut Grove, Norton, Malton, YO17 [email protected]

Planetary Alan Clitherow, Coldene, Bridgend, Ceres, Cupar, KY15 [email protected]

Solar Geoff Elston, 59 Nalders Road, Chesham, HP5 [email protected]

Variable Star Tracie Heywood, 20 Hillside Drive, Leek, ST13 [email protected]

Young Lucie GreenStargazers [email protected]

For further information about a section and how to submit yourobservations please contact the relevant Section Director using the

contact details above, or visit the section pages of the SPA website at:

www.popastro.com.

SPA Advisory ServicesAstronomy Tony Sizer, 88 Cumberland Avenue, Welling, DA16 2PUGCSE [email protected]

Astro Imaging Nik Szymanek, 186 Thorndon Avenue, West Horndon, Brentwood, CM13 [email protected]

Cloud Watch Terry Holmes, 34 Sycamore Road, Tipton, DY4 [email protected]

Instrument Ian Morison, 4 Arley Close, Macclesfield, SK11 [email protected]

Light Pollution Martin Morgan-Taylor, 39 Sports Road, Glenfield, Leicester, LE3 8ALLiaison Officer [email protected]

Follow us on Facebook and Twitterwww.facebook.com/popastro

twitter.com/popastro



SHOWCASEA selection of members images

◄ David Daviesimaged a “small”part of the VeilNebula, called“Pickering'striangle” . TheVeil is a largesupernovaremnant in theconstellation ofCygnus – so largethat it has severalNGC numberscataloguingdistinct parts ofthe nebula.Please see p35,for moreinformation fromthe Deep Skysection.

▲ This image of the aurora, showing the proton arc,was taken by Gordon Mackie from Castle Hill, Thurso onthe night of 28 September 2016. Please see p38 for moreinformation from the Aurora and NLC section.

▲ John Fletcher took this hand held snapshot of Venus andthe thin crescent Moon from the front door of Mount Tuffleyon 3 October 2016 at 18:01 BST. The image was taken with aCanon 5D Mark 111, EF 300mm FL IS USM prime lens at1/100 sec exposure, 400 ISO.

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