Wa 063 december 2013

The Southern Astronomer No.63 - December 2013

SOUTHERN ASTRONOMER THE

NEWSLETTER OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS

This issue The Ones To Watch Out For ISON Observing December Workshop preview Observing Project Observing Notes Star Map

pages 1 & 2 page 2

THE ONES TO WATCH OUT FOR THIS MONTH If you have never seen a comet before there is little doubt you will not be disappointed this month if you want to see one though not the one we had all expected.

ISON had its rendezvous with the Sun at perihelion (November 28) and it looked as if the ultimate battle between Fire and Ice went the way of fire with the possibility that the nucleus of the comet had broken up and the gasses boiled away.

page 3 page 3 page 5 page 12

Astronomy Meetings

However in the cold light of day it seems though the nucleus did indeed suffer trauma due to its close pass with the Sun a part or parts might have survived.

Worthing Astronomers (WA) occasionally meet at the Worthing Society of Model Engineers, Field Place, Durrington, Worthing BN13 1NP. Details of meetings, as and when, are further on in the newsletter.

Adur AS (AAS) meet at Southwick Christian Community Church, 1-5 Roman Crescent, Southwick BN42 4TY. Foredown Tower Astronomers (FTA) at Emmaus Charity Premises, on the corner of Manor Road and Drove Road, Portslade Old Village, BN41 2PA. Horsham AG (HoAG) meet at Christ's Hospital, near Horsham, RH13 0YP. Worthing Astronomical Society (WAS) meet at Emmanuel URC, St.Michaels Road, Worthing BN11 4SD.

Above: Comet C/2013 R1 (Lovejoy) captured by Nick Quinn on November 13 using a Starlight Xpress CCD camera.

AAS, FTA, HoAG and WA venues have off road parking facilities and grounds adjacent for setting up telescopes when conditions allow.

Astronomers will be trying to calculate a path for the remnant; ISON was never going to be 'the comet of the century' it will even be less likely now.

It may be a bit premature to bid farewell to ISON or the ISON we had hoped to observe. Keep watching the pre-dawn skies.

ISON was predicted to appear just below Lovejoy (at the 'foot' of Hercules) if it had appeared – lower picture left. Its orbit may yet be that.

WA £2 admission, Adur and the FTA charge £3 while WAS charge £4 at the door for non-members. All the above meetings above begin at 19.30hrs.

WA members will always be made welcome at these groups. More information 01903 521205 or 07801 692244.

A better bet mid-month is C/2013 R1 (Lovejoy).

Fuller details of what our colleagues in neighbouring societies are doing at their monthly meetings is on the page 2 Quick View Diary.

As the month progresses, Lovejoy will be moving in a southerly direction and getting lower in the sky.

Worthing Astronomers is a free to join society with a membership of over 280 persons all interested in the same hobby of Astronomy.

With the aid of this newsletter, regular star parties, workshops and public observing events we hope to encourage and share our interests in observing the sky with the public and our colleagues both in our own group and with neighbouring societies.

The BAA comet section predictions for the comet are for a binocular object rather than naked eye.

Above: Lovejoy at December 15 Predicted magnitude 5.9.

Graphics by Stellarium

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See Andy Lee's image of Lovejoy on page 11.

The Southern Astronomer No.63 - December 2013 QUICK VIEW ASTRO EVENTS DIARY

The Ones To Watch Out For cont.

December All times shown are Universal Time (UT equals UK civil time in winter (GMT)) 1 – Sunrise 0743h : Sunset 1602h Mercury 0.5° S of Moon (22h) 2 - AAS: Christmas Social 3 - New Moon (0h) 4 - Moon at perigee (10h) Pluto 1.8° S of Moon (23h) 6 - WA: Workshop & Seasonal Social (see page 3) 7 - Venus at brightest magnitude 9 - Moon: First Quarter (15h) 11 - A unique date (11/12/13) 14 - Geminid Meteor Maximum 16 - Aldebaran 2.6° S of Moon (02h) WAS: TBA 17 - Full Moon (09h) 19 - Jupiter 4.9° N of Moon (06h) Graphic by Stellarium FTA: Members Contributions Another comet is also in the sky during December but will require a telescope to observe it.

Moon at apogee (23h) 21 - Winter Solstice (17h) See note page 4 154P/Brewington is a comet with a period (as the P prefix suggests) of 10.66 years – an easy 22 - Regulus 5.1° N of Moon (19h) 23 - Ursid Meteor Maximum period to remember.

25 - Moon: Last Quarter (13h) Mars 4.4° N of Moon (23h) It lies just south of west mid-month and high up near the asterism of The Square of Pegasus 29 - Saturn 0.8° N of Moon (0h) (above). The graphic locates 154 P/Brewington at about 1800 UT on December 15 up in the Mercury superior conjunction (06h) west. As can be seen, Uranus is only a few degrees away. It will however require at least a 31 - Sunrise 0805h : Sunset 1607h

small telescope to see as the predicted magnitude* of the comet is 11.6m.

It will remain an early evening object moving only a little through that region of the sky until early February 2014 all the time progressively getting fainter. (*Magnitude predictions given here are correct as going to press. They can brighten or fade without notice).

WELCOME... ...to all our new members who have recently joined. ...AND HELLO To our many readers who receive this via their friends.

IMPORTANT NOTICE To all members. If at any time you are planning to change your email provider or email address please do not forget to drop us a line with the new email details if you wish to continue getting the newsletters.

On rare occasions we get email bounced back as email boxes are listed as full or no longer available.

Above: A telescope photograph by Rob Aro of Comet ISON – group observing report below

COMET OBSERVING REPORT Steve Bassett Rob Aro, Terry Gough and myself met up on Ditchling Beacon early on November 13 at around 0330UT to hopefully see C/2012 S1 ISON rise ahead of the Sun. The sky was very dark and clear; Orion was looking fantastic in the south-west with Jupiter shining brightly overhead and Mars with its unmistakable red glow in the south-east.

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If I receive too many bounce backs from an address I will delete it and no more newsletters will be sent. This ensures that any email we send out is not treated like 'spam'. BH

The Southern Astronomer No.63 - December 2013 Comet Observing Report cont.

After some initial set up issues we finally had Rob's scope and my camera pointing in the right direction and we started to take some test shots.

To our amazement the comet showed up straight away on Rob's screen filling quite a large portion of his field of view. The comet structure was clearly visible including the twin ion and dust trails in the tail that had only recently developed. Rob set his system to take a sequence of shots and attention turned to my camera that I had set up on a static tripod with a 50mm f1.8 lens.

The comet was very small on the cameras 3" preview screen but eventually we found it so I knew I was in the right area. I also then set my camera to take a sequence of short 10sec exposures at ISO1600, f2 (image on left). It was really incredible to see how the light was starting to increase rapidly with each image as the Sun was creeping ever closer to the horizon.

Eventually by about 0600UT the light was enough to obscure the comet from view so we decided to pack up and call it a night/morning. Hopefully this comet survives perihelion so we get more chances to image it [see report page one].

Above: Comet ISON by Steve Bassett The green colour is due to the chemical composition of the comet - diatomic carbon and not an artefact of photography.

WORKSHOP MEETING/END OF YEAR SOCIAL December 6, 2013 We will be holding the last Workshop of 2013 in early December at 19.30hrs. Member Andy Lee will be talking about 'Getting started in Astro-Photography'. It will also give us a chance to review the highs of 2013 and look forward to 2014, especially the early part where our contributions to Stargazing Live 2014 in early January and National Astronomy Week in the first week of March can be discussed.

We started the Workshops at the end of 2012 as an antidote to the washed out year we had had as a way of meeting up away from the eyepiece of the telescope, never thinking how popular they would become.

So we end the year with a presentation by Andy Lee and share some of his techniques for observing and a chance to meet, chat and exchange ideas, plus catch up on what we have all been observing.

Steve is a regular contributor to the newsletter.

Though ISON is lost Steve hopes to observe more comets in the future.

As it is the Social, the usual charge for entry has been waived so we hope to see you then.

OBSERVING PROJECT: VENUS IN DAYLIGHT Brian Halls VENUS IN DAYLIGHT Hunting for Venus in daylight with a telescope as described in the text is a project that requires a little skill and is best undertaken by an experienced observer as near accurate telescope alignment is required.

If you are still a newcomer to the hobby do not worry. You can still get a chance to see Venus in daylight; just read on.

Anyone who has tried to look at the planet Venus during the present evening apparition will have noticed how low the planet is in the evening sky.

A good south-westerly horizon at dusk is needed to see the planet and to compound the problem the path of Venus through the sky follows that of the Sun and is low.

If you do happen to capture Venus in the telescope at dusk it is a bright object and this can affect what you can see. The use of a W15 (yellow filter) or a W80 (blue) will alleviate the problem but have you thought of hunting out Venus in daylight? It is easy but requires some patience on the part of the hunter (see side notes Venus In Daylight.)

We have probably all heard or read about 'flying-saucer' tales where the UFO is actually a mistaken viewing of Venus. It does underline the fact that Venus can be visible in daylight under good conditions, and the amateur astronomer can take advantage of that.

What you need. If you are the possessor of a 'go-to' telescope that can do a one object alignment that job is easy. Set up the 'scope, align it with the another celestial object - the

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The Southern Astronomer No.63 - December 2013 Venus in Daylight cont.

Sun (bearing in mind to keep the optics of the telescope and finder scopes covered) and let the machine do the rest for you. For those like myself who have to put up with finding anything in the sky the good old fashioned way you will need to use the following method – it is best done when the angular distance between the Sun and Venus is at least 15°.

TIPS

To find your exact latitude and longitude use Google maps; a satnav will do the job You will need an equatorially mounted telescope that is set up with the right latitude angle – as well but, depending on its make and for us along this area of the Sussex coast it is 50.8°N (51°N will be fine). It will also need to sophistication you may need to take several GPRS readings off of it and take a mean be correctly aligned with the pole star – no mean feat in broad daylight so you will need to have your scope set up in its normal observing location and pointed approximately to the north value.

polar point – a compass with the magnetic variation allowed for is handy.

As mentioned earlier ensure that the covers on all optical devices are covered including the finder scopes. Point the telescope towards the Sun. You can use the shadow technique to approximate the alignment of telescope and Sun (see Tips). Once aligned set the setting circles (those dials with numbers on the mounting) to the RA and Dec of the Sun – then slew the telescope eastwards in RA until you have the RA of Venus (if Venus is an evening object).

Move the telescope in declination until the Dec of Venus is visible.

Carefully remove the covers off of your spotting scope. If you have been really lucky you will spot a little bright star shining in a blue sky – Venus. You will however, in all likelihood have to carefully scan for it. It will be close by.

Hopefully Venus will be apparent – and if you do see it it will be a most satisfying event. With the Sun well to the west of your telescope field of view, you can now take the covers off of your scopes aperture and get a look at our nearest planetary neighbour in daylight.

The picture on the right shows Venus on November 10 2013, at 1546UT – the Sun is still well above the horizon and the sky bright.

A W15 filter was used and the image is the result of stacking best frames in an AVI file in Registax. Using the traditional astronomical conventions, north is down and west (preceding) is to the left.

One thing observing Venus in daylight will not improve is the atmospheric rippling that affects objects observed close to the horizon.

Before looking for Venus in daylight check for the following: 1. You will need your telescope polar aligned as accurately you can.

2. You will need to have tables with the RA and Dec of the Sun and Venus for the previous midnight (0h) or the next midnight.

These tables are available from a variety of (free!!) software – WinJupos for example or, Stellarium will give real time coordinates for an object. If observing in the pre-noon try and use the table coordinates from the previous midnight; after noon use the data for the next midnight.

3.Shadow Technique. Unless you have a proper aperture solar filter mounted over the front of your telescope, you will need to do this. Point your scope in the general direction of the Sun. The shadow of the telescope will fall on the ground and the closer it gets to the Sun its shadow will grow smaller and smaller until it is as small as it will get. Never look at the Sun – even by squinting over the tube.

SOLSTICE NIGHT Linda Storey

This was my first view of Venus this apparition and I hope to get some more images at higher magnifications later on.

Saturday 21st December at the North Star public house, Littlehampton Road, Worthing any time from 8pm.

As the month progresses the phase of Venus will get smaller and smaller while its image in the eyepiece will get larger and larger. This is however off-set by Venus getting closer and closer to the Sun and thus making daylight Image credit: Brian Halls/Cokeham Observatory observation such as described more difficult.

On the plus side, the Sun is setting earlier and by mid month Venus will be showing a very deliberate crescent phase. For newcomers to the hobby, start looking for Venus as soon as the Sun has set or has disappeared behind a building in your vicinity and while the sky is still bright. A small telescope will show the phases quite well as will a good set of binoculars.

An easy way to look for Venus in daylight is to wait for it to become a morning object and start observing the planet in the pre-dawn; if your 'scope has a drive you will be able to follow the planet for some time after Sun rise – but always check the accuracy and reliability of the telescope drive, as the dangers of sunlight entering the optics of the telescope – and your eye – are going to be there.

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Traditionally some of us have got together to celebrate the winter solstice and enjoy a pre-Christmas drink (or two, if not driving!!!)

The North Star is on the A2032, almost opposite Durrington High School (and next to the Tesco petrol station)

The Southern Astronomer No.63 - December 2013 OBSERVING NOTES December Details in the Notes are for mid month (15th) unless otherwise stated and the times expressed are in UT (see note on time on page two Astro Events Diary) ASTRO LINGO

Sunspot activity over the last month or two has increased and a couple of large sunspots showed themselves during November.

Skywatchers member, Jonathan Green caught this moody photograph of the Sun late morning of November 16.

naked-eye – also referred to as unaided-eye (especially on the internet) is a term used to describe an object visible without binocular or telescopic aid by an observer.

The large sunspot on the lower left of the solar disk was just visible with unaided-eye if using a suitable filter (#14 welders glass).

In the case of the main article, a sunspot was visible without telescopic aid – though a suitable filter was needed to protect the eyes of the observer.

In the picture below captured by Brian Halls the larger active regions have been annotated.

#14 grade welders glass is suitable for short bursts of looking for naked eye-sunspots. Solar eclipse glasses comprised of Baader film are much better but may require a secondary filter to reduce 'point-of light' glare.

We hope to distribute free eclipse 'glasses' to members at the Workshop meeting on December 6.

SCT – short for Schmidt-Cassegrain Telescope.

These telescopes are notable for their short stubby tubes but have long focal lengths.

This compactness makes them portable. The two main manufacturers are Celestron and Meade, though Skywatcher also produce telescopes of this type.

The SCT is more properly a catadioptric telescope – sometimes referred to as a compound telescope - using the optical path of a cassegrain and the front end corrector plate of a Schmidt.

Originally invented in 1941 they have been produced by Celestron since 1970 – the first being a C8 (an 8” telescope); a C10 is a 10” instrument; C14 is a 14” telescope etc. They continue to use this simple labelling system today.

Photo: Jonathan Green; Nikon D7000 500mm telephoto lens

At the peak of sunspot activity – which we ought to be having as we are supposed to be at sunspot maximum, large naked-eye sunspots should be the norm, but instead

the quality of the sunspots is quite poor.

Of interest is the southern active region 1897.

This group of scattered small spots is highly active but under 'normal' solar maximum conditions this would be a group comprising much larger spots and, quite probably, also of naked-eye quality.

Below are two images, also by Brian Halls of AR 1899.

Photo: Brian Halls/Cokeham Observatory; 150mm OG, prime focus

Meade have been producing SCT's since 1980.

Their labelling system is confusing. A number of 8” telescopes were labelled as LX3, LX10, LX90, LX200. The LX 90 series range from 8” to 12” instruments while the LX200 range from 8” to 16”. A confusing system so it is not surprising that the company itself is also in a mess and may yet either fail or be sold. A shame for such good workmanship to go to waste.

Caveat Emptor! If buying a Meade telescope second hand do not go by the designation name alone. Ask for mirror diameter.

Above: White light image of AR 1899. A cluster of Above: Hydrogen-alpha view. Though a large sunspot the h-alpha visible region appeared small sunspots/pores can be seen to the right; 'quiet'. A filament can be seen upper left. these may be associated with the large sunspot.

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The Southern Astronomer No.63 - December 2013 Observing Notes cont.

Brian States observed the Sun on 28 days in October – another good month for Brian. The average October daily sunspot number derived from the observations of contributing WA members was R= 89.4. Sunspot activity was once again very much in the southern solar hemisphere and remains so as the pictures on the previous page tend to show.

Moon: Mid month the Moon is Full – its light all but drowning out the bright stars. Full Moon is perhaps the worst time to study it – there are no shadows throwing up crater walls or uneven lunar mare features. It is a good time to look at the bright features of the Moon called 'rays'.

Some of the craters – Copernicus and Tycho for example – have ray features associated with them. Rays appear to be the 'splash' material from crater impacts.

The post Full Moon image on the left shows some of the more familiar rays.

A is for Aristarchus – hardly a ray system but the crater is so bright that it is visible in earth-shine.

C is for Copernicus – a relatively young crater at 800 million years old. The ray system from this crater can be followed over the disk. To a lesser degree and not as obvious as it neighbour, K is for Kepler. Its rays are dilute by comparison to T for Tycho whose ray system is probably the most prominent of the various rays.

Photo credit: Chris Pennells

One can imagine a massive asteroid impact hitting the Moon and bright ejecta material is splattered across the lunar landscape for hundreds of kilometres.

Copernicus' rays are not as distinct as those of Tycho but under sunlight they appear to have interesting structure while those of Tycho travel over a thousand kilometres and are visible in earth-shine. A close look at some of the rays shows them to not to emanate from the crater itself but sometimes at right-angles to it. Something else to look at is that the rays if tracked back to Tycho stop at a dark rim of material that surrounds the crater – an effect it is believed of the post impact environment.

With the Moon much higher in the sky for much longer periods now perhaps is a good time to acquaint yourself with our nearest space neighbour and the only other world that humans have set foot on.

Quick Glance Lunar and Planetary visibility mid-month

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FOR SALE Skywatcher SKP13065EQ2 Reflecting Telescope Diameter 130mm Focal length 650mm 360 degree slow motion control cables Dual setting circles Adjustable height Aluminium tripod Adaptor for piggy back camera attachment Equatorial mount for easy tracking Red dot finder Interchangeable eyepieces : 25mm wide angle eye relief 10mm eyepiece 2x Barlow lens 5mm lens Moon filter £120 for the lot If you are interested contact Sojnia on 07891 757541 Editors Note: A chance perhaps for a starter to get themselves a good telescope with accessories at a bargain price or, do you know someone who might like the above as a present?

The Southern Astronomer No.63 - December 2013 Observing Notes cont.

Planets: Mercury rises and sets before and after sunrise and is poorly placed mid month, while Venus mentioned in an earlier article on page 4 is visible low in the south west. By the end of the month it will be in the glare of the setting Sun and will be placed briefly for observing before setting about an hour and three quarters after the Sun. By the end of December 1: 7:55, 17:50; 2: 3:46, 13:42, 23:37; 3: 9:33, 19:28; 4: 5:24, 15:19; 5: 1:15, December it will appear as a thin crescent about 5% illuminated.

Transits Times of the Great Red Spot (GRS) of Jupiter

11:11, 21:06; 6: 7:02, 16:57; 7: 2:53, 12:49, 22:44; 8: 8:40, 18:35; 9: 4:31, 14:27; 10: 0:22, 10:18, 20:13; 11: 6:09, 16:04; 12: 2:00, 11:56, 21:51; 13: 7:47, 17:42; 14: 3:38, 13:33, 23:29; 15: 9:25, 19:20; 16: 5:16, 15:11; 17: 1:07, 11:03, 20:58; 18: 6:54, 16:49; 19: 2:45, 12:40, 22:36; 20: 8:32, 18:27; 21: 4:23, 14:18; 22: 0:14, 10:09, 20:05; 23: 6:01, 15:56; 24: 1:52, 11:47, 21:43; 25: 7:38, 17:34; 26: 3:30, 13:25, 23:21; 27: 9:16, 19:12; 28: 5:08, 15:03; 29: 0:59, 10:54, 20:50; 30: 6:45, 16:41; 31: 2:37, 12:32, 22:28 Reproduced courtesy of Sky Publishing

Uranus and Neptune will be early evening objects for the month while Jupiter will be the planet that dominates the evening sky as it heads for opposition in January. Good evening views of the GRS maybe had on December 3,5,7,8,10,12,15,17,19,20,22,24,27,29 and 31.

In the side bar, a list of times for the month is given.

Mars rises in the early hours and those who have recently been observing early morning comets have noted how bright it is, while Saturn rises an hour before the Sun and will be visible for those early risers.

After the solstice the Sun will set a little earlier but it will be hardly noticeable. By the end of January however, brightening in the evening and morning skies will be more apparent.

The GRS will be well placed for observing 50 minutes or so either side of the times given.

Meteors and Comets: The Geminid Meteor Shower is considered to be one of the most reliable showers. This year it peaks in the evening of December 13/14 with the start of the shower occurring about week METEOR OBSERVING TIPS earlier. The peak period lasts about a day so with weather allowing there will be a chance of seeing something. The Moon however is few days short of Full and its light may cause a The following list is only a brief description of problem, though with meteors best seen before the dawn the Moon will be setting in the west what is needed. A full and informative guide while Gemini is still high overhead. The zenith hourly rate (ZHR) is over a 100 so we may get to Meteor Astronomy can be found at: a bit of a show, weather and moonlight permitting. http://www.meteorwatch.org/scienceobserving/how-to-observe-meteors/.

Quick Start Guide Requirements: 1. A good star map; red lensed torch.

2. Accurate time piece, pencils and paper.

3.A comfy seat; warm clothing, food , drink and, a ruler.

Whereas most meteor showers are associated with comets, the Geminids' progenitor object is an asteroid - 3200 Phaethon – possibly a dead comet but, no one knows for sure.

“As the name implies, a meteor watch involves concentrating on the sky and noting details of any meteors seen. Solo observers should watch the sky 50 degrees above the horizon (about the same altitude as Polaris from the UK), and 30-40 degrees to one side of the shower radiant expected to be active on the night in question; most meteors should be seen here.

As each meteor appears, regardless it was a shower member or a random sporadic, estimate how bright it was, and give its time of appearance to the nearest minute in UT. Mentally project its path in the sky backwards. If the projected path intersects the 8degree radiant circle, the meteor is a shower member. Otherwise it is a sporadic. Those with paths tangential to the radiant should be considered as possible shower members. If a stick, or piece of string is held up against the meteor path when the event is seen, this will give you time to collect your thoughts after the meteor has vanished.

Note what you see using the paper or some form of recorder.” (Based upon BAA Meteor Section guide to meteor observing)

Geminid radiant (arrowed) close to Castor

Ursid radiant (arrowed)

Graphics by KStars

The little observed and less famous meteor shower, the Ursid's appear between December 17 and 25 with maximum occurring on the night of December 22/23. Moonlight should be good by not interfering and as the radiant point is circumpolar in Ursa Minor it will always be in the sky. It is considered a favourable shower this year. It is associated with comet 8P/Tuttle.

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The Southern Astronomer No.63 - December 2013 Observing Notes cont.

Stellar & Deep Sky: We are going to take our usual look at what is in the sky but we will occasionally use the 'star-hop' method to find our way around. A full explanation of the term is given in the adjoining column. A good test subject is the constellation of Taurus,The Bull, though mid-month the Moon will be in the constellation – best to try this exercise early or later in the month when moonlight will not interfere.

Start with the star Altinak (the left hand star in Orion’s Belt.)

STAR HOPPING

Try and draw an imaginary line that passes through the three Belt stars and move upwards until you come to a bright orange-red star – Aldebaran. (1) That was the first star-hop.

Didn't hurt did it?

What is meant by the term 'star-hopping'? It is in basic terms the practise of using certain bright stars as guides or sign-posts to help move around the sky to find interesting stars or deep sky objects (DSO's.)

The use of computerised telescope mounts (or 'go-to') has made star-hopping a bit redundant nowadays but it is still a useful skill to acquire and use. To correctly set up a go-to telescope still requires the user to know their way around the sky; understanding what star is which for the alignment process for example. The same goes for star-hopping. A basic recognition of the constellations and their stars is required but unlike using a go-to instrument, the star-hopper will get to know the positions of various objects in the sky far better. It is a really good way of learning your way around the stars.

Take your second hop further up from Aldebaran until you get to a bright cluster of small stars – The Pleiades. (2) Head back down the way you came to Aldebaran (3) and then turn eastwards and follow a line to a bright star ζ (zeta) Tauri (4).

Above ζ is faint fuzzy patch – you will need a telescope for this.

This is the Crab Nebula – remnants of a supernova that exploded 7000 years ago.

Star hopping once honed is a quick way to swing a telescope or even binoculars to a position in the sky that you may require while the go-to telescope whirrs away like a coffee grinder in the dark, slowly tracking to the point that it is looking for.

The best way is to work on some examples and we'll be looking at some stars that are visible in the seasonal skies to practise star-hopping on. Each month and when 1. The area around Aldebaran is a rich one for stars. A lot of the stars are part of an open appropriate we shall have a star-hopping cluster – The Hyades. which lies (at present estimates) at 150 light years away. This V shaped section in our Sky Notes to help you find cluster gives the 'face' of The Bull – a chart is on the next page. Almost midway between γ objects in the sky.

Taurus Star-Hop Graphic by KStars

and α is the brightest star in the group, θ2 (theta). This is a blue-white star of 3.4m it is also part of an open double star system with θ1 which is a yellow star. They make a nice appearance in As you get more used to the sky, you will even develop your own star-hopping binoculars or a small telescope. techniques.

2. From one open star cluster to another – The Pleiades. The brightest star of the group (see chart next page) is Alcyone at 2.8m a blue-white star, brightest in a multiple star system, two fainter companions are both 8m while there is a fainter companion at 8.6m. Maia is also a hot white-blue star at 3.47m. An interesting star is Pleione. It is 3.5m and a variable star – known to variable star observers as BU Tau. It shines from 4.77m to 5.5m when the star ejects a shell of gas that surrounds it. It is believed that the variability may be due to the rapid rotation of the star – it rotates a hundred times faster that our own Sun (which rotates in about 27 days). All the stars in the cluster are blue-white giants.

3. We hop back to Aldebaran. Though it appears to be part of the Hyades, this is just a line of sight illusion. The star is much closer to Earth that those in the cluster.

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The Southern Astronomer No.63 - December 2013 Observing Notes cont.

There are so many stars in the Hyades, most have numbers.

THE MESSIER CATALOGUE Charles Messier was a French astronomer with an interest in observing (and discovering) comets.

Centre near the left edge is α (alpha) Tauri or Aldebaran.

There as a problem however. He would spend hours at the telescope studying the sky when his eye would catch a faint misty patch. He would then return to the same spot night after night to look for movement of the object against the sky. More often as not the object remained in the same place.

He had wasted hours observing not a comet but objects we refer too now as nebula or even galaxies.

In this view north is up and east to the left as is the graphic of The Pleiades, below.

So frustrated was he that he produced a list of objects that would not be confused with comets. It was first published in 1774 and was then finally updated in 1781.

The Hyades

The catalogue remains in use today and the objects are listed by the initial M followed by their number in the listings.

Graphic by Carte du Ceil

In mythology, the Pleiades and The Hyades are all sisters.

In reality the two groups are comprised of different types of stars.

The Pleiades are bluewhite stars while those in the Hyades comprise predominantly (though by no means all) of yellow-orange stars.

There are 103 Messier objects catalogued by him with a further seven objects (104 to 110) added later by himself and colleague Pierre Mechain.

There are some oddities in the listings. The Pleiades are listed as M45 yet this object could hardly be mistaken for a comet as it has been known since antiquity.

Messier discovered (or co-discovered) 13 comets yet it is for his work on what we now term deep-sky-objects that he will forever be famous.

The Pleiades

Graphic by Carte du Ceil

Aldebaran lies at about 68 light years from Earth and is an orange and slightly variable star.

Its Arabic name translates as 'The Follower' – no doubt due to its following of The Pleiades. across the sky. It may also be part of a multiple star system but as yet, there is no firm conclusion as to this.

4. Out last hop is from Aldebaran to ζ (zeta) Tauri – the star at the end of one of the horns of The Bull. It is what lies close to ζ that is of interest and a telescope will be needed for this.

In the finder scope bring ζ onto the cross-hairs. Now bring the cross-hairs about two full moon diameters (about a third of the way to the edge of the field of view) towards the north west of ζ (see graphic next page).

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The Southern Astronomer No.63 - December 2013 Observing notes cont.

Using a low power eyepiece at the telescope and if conditions allow, you will see a faint but reasonably large blob of light. If you cannot quite make it out try and focus your eye towards the edge of the field of view and use averted vision. Some observers report that this helps.

What you are looking at is The Crab Nebula – or object number one in Charles Messier's catalogue, hence its other name, M1. This is all that remains of a massive supernova that in July 1054 shone brightly in daylight for the better part of a month; it shone as a bright 'new' star in the evening sky for about two years after that before it faded from view.

Also known as NGC 1952, it is classified as a diffuse nebula.

The view in the left hand graphic is a finder scope view of ζ and M1 or a view thru a Newtonian telescope.

Using a refractor with a star-diagonal or an SCT/compound telescope the E-W positions will be mirror imaged and possibly the N-S will also be reversed if the telescope produces a noninverting image Graphic by Stellarium m

M1 is about 8.4 and so will visible – albeit faintly – in a moderate telescope with a good magnification. Identified in the telescopic age by English astronomer John Bevis in 1731 it was then rediscovered by Charles Messier in 1758.

It was born out of a cataclysmic death of a star some 5-6000 light years away and the gas and dust are still expanding. Photographs of the nebula taken at a few years interval show changes to the structure of the expanding gas cloud. As it expands it gets fainter and it is likely that the object is getting fainter as it grows and may be fainter than it was when Messier catalogued it as object number one in his list of objects not to be confused with comets (see previous page).

The name Crab comes from the Earle Of Rosse who observed it with his giant telescope during the nineteenth century and its description when viewed through the eyepiece.

Taurus The Bull, is not the only constellation on view at night. As the star map on the back page shows, high over head is Auriga The Charioteer sometimes known as the Winter Hexagon asterism.

The bright star Capella (α Auriga) is prominent – it is the sixth brightest star visible from our corner of the galaxy and the fourth brightest star visible in the northern hemisphere. With the unaided eye or a pair of binoculars it looks like a single point star but it is actually the brightest star in a multiple star system – two pairs of stars in binary associations with each other. One pair are giant G-class stars believed to be on their way to cooling down to become red giants, while the other pair are red dwarfs.

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CONSTELLATION TRIVIA Taurus The Bull is said to depict either the Minotaur defeated by Theseus or the Bull that was the disguise used by Zeus while he chased the attractive mortal women of Greece and its neighbourhood. Alternately it might be the Cretan Bull that Heracles had to defeat as part of his Twelve Labours (in which case what we call Orion might not be Orion...another story for another time...)

The concept of a Bull almost certainly pre-dates the Greeks; the Babylonians knew it as the Heavenly Bull while the Egyptians used the same description for it.

During the Early Bronze Age the Vernal (Spring) Equinox occurred in Taurus while 2300 years BCE the Sun was close to the Pleiades at the Equinox.

Auriga The Charioteer, in Greek mythology – where most of our constellation identities originate – is identified with the inventor of the four wheeled chariot, Erichthonius.

He uses the chariot to capture the heart of love while in another story he escapes the romantic clutches of his amorous step-mother only to be killed by a chariot.

To the early peoples of Mesopotamia the constellation was identified with a shepherds crook. To the later Bedouin astronomers the constellation is a herd of goats.

Some later representations of the constellation show Auriga as a goatherd – mixing the mythologies of different cultures.

The Southern Astronomer No.63 - December 2013 Observing Notes conclusion

Auriga is close to Taurus and we can use the star hop method to find our way around.

Using ζ Tauri, run an imaginary line to the north and you will come to the bright star Alnath; north of this star, and if using a lower power eyepiece or finder-scope three DSO's are visible – M36,37 and 38.

THE SOUTHERN ASTRONOMER JANUARY 2014 ISSUE The Ones To Watch in 2014 – a list of astronomy highlights for the coming year plus the usual observing notes and sky diary for the month and more

Graphic by Kstars

For binocular users, why not try and look for M36. This is an open cluster of stars sited in the Milky Way. It lays at a distance of over 4000 light years away and is 6.3m.

For a telescope user there are about a dozen bright stars. It is best seen using a low power.

M37 is again an open cluster at 6.2m which puts it into the range of small instruments. It has been described as looking a little like a globular cluster in a small telescope but a moderate to larger instrument will show individual stars – some estimates put it at 150. An orange star lies near the centre. This distant open cluster is about 4500 light years from us.

M38 is a faint open cluster laying 4200 light years distant and is 7.4m. It can be better resolved in a small telescope compared to M37. A fuzzy haze of light with 5 to 10 bright stars can be seen, depending on the seeing. A moderately large telescope (150mm upwards) can be used to pick out more.

COMET LOVEJOY

MONTHLY SKY MAP The star map on the next page shows the position of stars and constellations on December 15 at about 21.30UT The map is created using the free Stellarium software.

This is a useful tool for amateur astronomers and can be downloaded from www.stellarium.org Andy Lee took this picture of C/2013 R1 (Lovejoy) on the morning of November 15. It is

comprised of 58x1 minute exposures and stacked.

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The Southern Astronomer No.63 - December 2013

The sky from Sussex at around 20.30UT on December 15 Contributions – written articles (preferably word processed), photographs or letters to the editor for the January 2014 issue should be in by December 27 and sent to the editor at the contact address: info@worthingastronomers.org.uk Detailed occultation predictions in PDF format may be had by contacting the same address. (Please include exact latitude, longitude and approx height above sea level – these can be found using a service like Google Earth, for example.)

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