The Southern Astronomer by Brian Halls

The Southern Astronomer No.68 – May 2014

SOUTHERN ASTRONOMER THE

NEWSLETTER OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS

MARS AT OPPOSITION

This issue Mars at Opposition 'Observing the Planets' Workshop St Audries Bay Star Party Sleepy Satellite? The Polaris Hour Sky Notes for May

front 2 4 5 6 7 -12

Astronomy Meetings All the groups listed below begin their meetings at 19.30hrs BST Worthing Astronomers (WA) meet on the first Friday every two months (February, April, June, August, October and December) Goring URC, corner of Shaftsbury Avenue and Barrington Road, Worthing, BN12 4EA. Admission £3. Adur AS (AAS) meet at Southwick Christian Community Church, 1-5 Roman Crescent, Southwick BN42 4TY.Admission: £5 for guests, £3 for members. Foredown Tower Astronomers (FTA) at Emmaus Charity Premises, on the corner of Manor Road and Drove Road, Portslade Old Village, BN41 2PA. Admission £3 for guests. Worthing Astronomical Society (WAS) meet at Emmanuel URC, St.Michaels Road, Worthing BN11 4SD. Admission: £4 for guests. AAS, FTA, and WA venues have off road parking facilities and grounds adjacent for setting up telescopes when conditions allow. WA members will always be made welcome at these groups. More information 01903 521205 or 07801 692244. Fuller details of what our colleagues in neighbouring societies are doing at their monthly meetings is in the Quick View Diary, page two, Worthing Astronomers is a free to join society with a membership of over 300, 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, our colleagues in our own group and with neighbouring societies.

The planet Mars comes to opposition and closest approach to Earth every two years and these give us a chance to get a relatively close glimpse at the planet. Not all these glimpses however are really good ones. This year, Mars is low in our skies and the effects of atmospheric rippling may cause problems, while the diameter of the planet is a mere 15”-arc, so the diameter of the planet as seen in a good eyepiece is not going to be large. These however are not problems – just challenges. Our members have taken their chances to grab views of Mars during this part of the apparition of the planet. On the night of opposition Steve Bassett, using his 15cm Newtonian, 3x and 5xbarlow lenses and an SPC900 webcam took a series of images at differing magnifications totally about 4000 frames. The result at the top (right) shows the bright northern polar cap at the top and the light and dark desert regions of the planet.

Mars on the night of opposition © Steve Bassett

A few days previously, Gary Isherwood using a Nikon camera captured the planet the north polar cap is clear at the top left while the dark smudge area underneath the polar cap is Acidalia Planitia. The dark features to the lower right of the disk are Syrtis Major Planum and close to the limb of the planet is the Tyrrhena Terra. During May the angular diameter of the planet is still about 14”-arc and the planet remains a -0.8m bright object in the light evening skies. The next best opposition is during late spring 2016, when the planet will still be low in our skies (it never does get too high from the southern UK) but its angular diameter will be 25”-arc.

Mars on April 6 © Gary Isherwood To make the most of the appearance of three planets in the evening sky, on the evening of May 10 we plan to hold an observing session down on the Prom at the bottom of Grand Avenue, from about 8 p.m (BST) onwards. Jupiter will still be high in the western sky, the Moon will be almost due south and Mars will be about 8° east of the Moon. Saturn will be about 10° above the horizon in the east at about 9.30 p.m (BST)

The Southern Astronomer No.68 – May 2014 WORKSHOP REPORT April 4, 2014 OBSERVING THE PLANETS Our first meeting at the new venue was held on April 4 and the subject was Observing the Planets. Brian introduced the meeting by speaking about how observing the planets by amateurs has changed over the years. Forty years ago large telescopes that would give pleasing views of the planets - say a 6-inch (152mm) Newtonian reflector bought new - would cost just over a hundred pounds; at 2014 prices that would equate to about £1500. So in real terms the prices of a basic telescope have come down and coupled with the mass production techniques pioneered by the Chinese, telescopes of sizes that might have cost many thousands of pounds 40 years ago, are now well within the purchasing power of individuals. For many years observing of the planets was very much a pencil and paper pastime - drawing the shadings of the clouds of Venus, the polar caps and markings on Mars or, the storm belts of Jupiter was something that was done by the amateur. Over the last 15 years or so leaps and bounds in technology have allowed the amateur astronomer to produce world class images of the planets that was, only up to a few years, the province of a professional observatory or even, a planetary space probe.

QUICK VIEW ASTRO EVENTS DIARY

May All times shown are Universal Time (UT = BST minus 1 hour) For AAS, FTA and WAS details, see front page

1 - Sunrise 0437h : Sunset 1924h 5 - AAS: Guest Speaker, Dr David Whitehouse 6 - Moon at apogee (10h) John began by saying that when he started out (also about 40 or so years ago) photography 7 - Moon: First Quarter (03h) of the planets was done with a single lens reflex camera and film. After many failed attempts 10 - Saturn at opposition (18h) he gave up with photography. One of the main problems, apart from getting exposure and WA: Planet Observing Evening other camera settings just right was the effect of atmospheric rippling. 11 - Mars 2.8°N of Moon (11h) 14 - Full Moon (19h) Then a new development occurred - video cameras. John realised that video could be used to 15 - FTA: Our Vital Moon capture real time images of the planets and he along with some colleagues at the then 18 - Moon at perigee (12h) 19 - WAS: Fourteen Pioneers of Brighton Astronomical Society jointly invested in a video tape camera and this was used to Astronomy produce some satisfying images using a 10-inch reflector. Then came a further development 21 Moon: Last Quarter (13h) digital video. 25 - Mercury 23° eastern elongation(06h) 28 - New Moon (18h) John had gone through his records and showed some of these early video images from tape 31 - Sunrise 0355h : Sunset 2007h

Brian then introduced our guest speaker John Bush, to speak about imaging the planets.

and digital formats and the ones of Mars and Jupiter were fine images.

Then in the early 21st-century came the conference camera - the webcam - and one in particular, the Phillips Tou-Cam which was discovered to be a good imaging device for capturing images of the Moon and the planets.

A reconfigured 'Tou-Cam' with an eyepiece adaptor

The webcam, when plugged into a portable PC and the camera attached to the eyepiece end of a telescope can be programmed using the software that comes with it, to capture short sequences of video in the AVI format.

These video sequences, some comprising of hundreds or even thousands of individual image frames, are then processed using software such as Registax. These programs then find the best images in each sequence, stack them together and then the operator can make adjustments which sharpen and enhance the image. By shooting long sequences and fast frame rates, the effects of atmospheric rippling are negated as processing software will identify the best images and choose similar frames to add to the stack.

The Southern Astronomer No.68 – May 2014 Workshop continued WEBCAMS

One problem with webcams in astronomical imaging is that they are unable to cope with large amounts of data going down the USB connector (bus) to the PC. Manufacturers have been producing 'scientific' grade cameras to sort out this problem. John uses the Image Source DMK mono (black and white) camera as it uses USB2 technology for faster delivery from the camera to the PC and can shoot frames as fast as 60 frames per second.

The original Tou-Cam is no longer available though the SPC900 is a popular unit (Steve Bassett uses one) or one of the following:Logitech QuickCam Pro 3000 Logitech QuickCam Pro 4000 Creative NX Ultra Creative Live Ultra 3Com Home Connect

A DMK mono camera – a x2 barlow lens has been added to the eyepiece adaptor. © Brian Halls

A mono-DMK comes in at about £350 but other manufacturers are producing similar 'scientific' grade cameras at lower prices - some available to image in colour - a great advantage when imaging colourful objects like Mars, Jupiter or Saturn.

Jupiter and moon © John Bush

John explained that he uses his camera in association with a filter wheel to produce a standard mono image (luminescence) and three colour images of the same object, in red, green and blue (RGB) using appropriate coloured filters. By processing these images in Registax or similar and then combining the results using standard photography processing software such as Photoshop he can combine and produce a colour image, some of which he showed - Jupiter and its Great Red Spot being the most obvious effect of this processing technique.

John concluded the talk by showing another facet of the power of a webcam type camera linked to a telescope - a tour of the face of the Moon. With the music of the Blue Danube playing in the back ground and in a scene reminiscent of the Journey to the Moon sequence from Kubrick's '2001' John's camera viewing through his 8-inch Celestron, gave the audience a feel of flying across the face of the Moon. During the end tea break John answered many questions from interested members. John's talk showed that what can be done without using very expensive CCD cameras. All that is required is patience and perseverance. Many members are producing fine images of deep-sky objects, plus planetary and lunar images – some taken using the methods described by John above or with the 'standard' cameras – mainly DSLR (digital single lens reflex).

These are standard webcams and will need adjustments to make them work. Alternately, and for a little bit extra, buy a webcam already re-engineered for astronomical use.

LRGB FILTERS These are dedicated for imaging work and may be advertised as CCD filters. Generally there are three – Red, Green and Blue. Occasionally they are sold with a fourth – non-coloured - filter, usually an IR blocking filter. Ordinary coloured 'eyepiece' filters are not suitable. Prices can range from £80 to £150 upwards for a set. Used with a mono (black and white) imaging camera and placed behind a filter wheel, AVI sequences are filmed through the red, green and blue filters successively using the same settings for each colour. A fourth image sequence is made without a coloured filter (or with an IR blocking filter) and is referred to as the luminescence shot. All four AVI sequences are processed in Registax or similar program. The four resulting images are then placed within an image processing program such as Photoshop and recombined to produce a final coloured image.

PLANETARY-LUNAR PROCESSING PROGRAMS

Perhaps might be a good time for our members to exhibit their images to a wider audience – a few members use the image/photography website flickr to share and showcase their own Registax – probably the most famous of the personal pictures. Is there anyone who would like to manage a Worthing Astronomers flickr image processing programs. It can also be page? used for post processing images If so drop us a line at info@worthingastronomers.org.uk Our next workshop in June is hoped to be a practical hands on lunar/planetary imaging project. More details in the next Southern Astronomer.

AutoStakkert – a program that Damien Peach, one of the UK's foremost planetary imagers uses and recommends.

The Southern Astronomer No.68 – May 2014 ST AUDRIES BAY STAR PARTY Steve Bassett A small contingent from the Worthing Astronomers, myself included, headed down to the Somerset coast for the St Audries Bay star party on the weekend of April 4th.

For a new event it boasted a great line up of speakers - John Slinn, founder of Disciples of the Dark Arts, Nigel Bradbury, commentator on the Aurora flights, Nick Howes, professional astronomer at Kielder Observatory and Damien Peach, world renowned planetary imager. There were also trade stands representing Io Astronomy (www.hampshireastronomy.co.uk) and SCS Astro (www.scsastro.co.uk).

This new addition to the star party calendar is on a camp site located just to the east of Minehead in West Quantoxhead and promised some very dark skies for observing and imaging under.

Rob Aro and I arrived at around 3 p.m. on the Friday afternoon to Sadly on both evenings the weather never really cleared. We did a patchy sky but the forecast for the evening did carry some get a very brief clear patch on Friday afternoon/evening which hope. gave us a chance to do some solar observing through John Slinn’s solar scopes and we had a few small patches later in the We were immediately struck by how beautiful the coast line was evening which gave us glimpses of Jupiter and the Moon. with views across to Minehead in the West and out across the Bristol Channel to Wales in the North and there wasn’t a street We spent our time tinkering with set ups and exchanging tips and light to be seen!! ideas. It was great to be in a place where everyone shared a common interest. Looking forward to next year!! As more and more people started to arrive there was a great atmosphere building and it was really nice to put faces to names A huge thanks to the staff at St Audries Bay Holiday club and that we had conversed with in the past on the Facebook groups also to Andy Lee for putting in the hours helping to arrange the but never actually met. event!!

View across St Audries Bay All pictures © Steve Bassett

Telescopes and sun-dog at St Audries Bay Star Party

COMING UP IN JUNE... Rosetta: Rendezvous with a Comet, talk by Professor Andrew Coates (MSSL) As part of the Steyning Festival, Professor Coates will talk about Rosetta, ESA's mission to comet 67P/Churyumov-Gerasimenko. Later this year the spacecraft will rendezvous with the comet and deploy a lander named Philae. The lecture takes place at 7.45pm on Tuesday 3rd June in Steyning Methodist Church, doors open 7.15 p.m. for tea & coffee. Tickets cost £5 and are available from the Festival box office (Steyning bookshop), and via the website http://www.steyningfestival.co.uk.

SLEEPY SATELLITE? THE MOON AND US

The Southern Astronomer No.68 – May 2014 Brian Halls Last winter the UK witnessed some of its worst weather for many decades. To a certain degree this was bought about not just by 'climate change' but by an old friend - the Moon.

As the early conditions of the solar system settled down, the Moon became the constant companion of our planet. When we observe the Moon we see that its surface has been battered by impacts over billions of years. The Moon has acted as a shield, capturing incoming impactors onto its own surface or deflecting them off into space and away from the young Earth.

As the weather fronts off of the Atlantic with their high pressure hit western Europe (December 5/6, 2013) - bad storm conditions as they were - it coincided with a 'spring tide' bought about by a new Moon (December 3, 2013) that was close to perigee, the closest point in the Moons orbit around the Earth (December 4, 2013).

The tidal influence of the Moon on the surface waters of our planet may very well have affected how life formed on our world; it may be no coincidence that the lunar orbital period of 28 days finds its way into varying aspects of human physiology.

When those meteorological and astronomical conditions combine and close to the mid winter period as well, the news was not Our planet is tilted by about 23o from the plane of its orbit around going to be good for anyone in the way of the coming storm. It the Sun. It is this tilt that gives our world the varying seasons. was in many ways, the 'perfect storm'. The Moon helps by keeping the tilt steady; if the Moon was not there, the tilt would vary over a few hundreds of thousands of But still, things are not all that bad. Without the Moon our lives years bringing extremes in climate conditions - extremes that would be very different; indeed we might not even exist if the would perhaps not have allowed for complex life across its Moon were not there. surface. Present theory has the Moon being created by a chance collision between a Mars sized planet (they even have a name for this small planet, Theia) and a proto-Earth in the early chaotic days of the solar system perhaps as little as 95 million years after the start of the solar system.

The Moon is a Goldilocks object; it is just the right size - not too small, nor too large; not too near, not too far away; it is in just the right place. We are probably more aware of the lunar influence due to the tides which ebb and flow on our coast. For a maritime nation such as ours, the tides have played an important part in national history (Sir Francis Drake calmly playing boule at Plymouth Hoe could not meet the incoming Spanish Armada until the tide had turned); and commerce – the British fishing fleets once fed the nation. The Moon itself has played a serious part in our more secular world. It has inspired poets ('The Moon in June..'); for thousands of years it has been the night time light by which humans went about their nocturnal business even very much up to recent times – the late summer full moon giving light to the harvesters. The Full Moon to country folk even into the early/mid years of the last century, was known as the Parish Lantern, the light by which people made their way home after dark.

Artist impression of the Earth-Theia impact

So. We owe the Moon an awful lot. If human life had adapted without a Moon would humans have reached out into space with nothing nearby to act as a goal to aim for?

For the deep sky astronomer, a moonless night is a good night as the bright light from a Full Moon can ruin observations yet, with out the bright Full Moon our lives might be so very different.

The debris thrown off by this collision created a ring system - like a cruder version of the rings of Saturn - around the Earth for a brief time before the ring debris began to coalesce into an orbiting body around the Earth.

When astronomers search for extra solar planets, like Kepler 186-f recently announced in the April issue of Science as being the most earth-like planet yet found, they may need to look a bit closer at these worlds and place them under closer scrutiny - a large orbiting satellite close by might be the real first tell-tale indicator that that world may indeed be an abode for life.

When we observe the Moon today some of the large dark lava plains on the Moon we call mare, may have been caused by some of the larger bits of this orbiting debris striking the nearly formed Moon - the ages of these lunar seas being counted in the billions of years.

THE POLARIS HOUR Setting Up a German Equatorial Mount

The Southern Astronomer No.68 â&#x20AC;&#x201C; May 2014 For a brief period at UT midnight, a few days either side of May 1 and Nov 1, Polaris is aligned above (or below) the north celestial pole (NCP). At midnight on May 1, Polaris lays below the NCP. (see graphic below).

One important point to remember. The polar-scope that comes with your GEM is likely to be an inverting telescope (it will give you views upside down) so when using this sort of instrument Polaris will be above the NCP at the end of April/beginning of May. Of course, it is not necessary to wait until the beginning of May or November 1st of each year - especially in our cloudy climate. It is possible to use the 'clock' dials fitted on the polar axis by the mount manufacturers to also get an approximate positioning of Polaris at any time of night relative to the NCP. (These settings will be dealt with in another article). Even easier of course is to use a simple computer program; free to download from here is this one: http://myastroimages.com/Polar_FinderScope_by_Jason_Dale/

Polaris lays below the NCT

Accurate polar alignment is a necessity if using your telescope to take time exposure images of faint objects like deep sky objects or comets.

Image by Stellarium

This is an ideal time for those who have their equatorial mounts (EM) permanently set up, to check if their equipment is correctly polar aligned, or alternately set up a semi-permanent location in the back garden

It is also extremely useful if trying to find objects via the right ascension (RA) and declination setting circles. (Again, a topic of another piece to appear in the Southern Astronomer). For portable telescopes being used on a field-trip a simple glance up the polar axis to spot Polaris and place it as centrally as possible maybe is all that is required.

Most good quality German EM's come with a small polar telescope already fitted inside the polar axis or one to insert for alignment purposes.

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This polar telescope usually has a graticule on it as in the picture top, next column or, even a wide angle view of some of the neighbouring constellations.

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Around the centre of the graticule is a small circle; ground on the circle is an even smaller circle.

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Assuming the telescope mount is correctly aligned with the local meridian, it is just a case of going out at midnight and checking to see if Polaris is sitting inside that small circle.

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If it is not, you will need to use the adjustment screws of the mount (ideally with the telescope tube removed) to adjust gently.

OBSERVING NOTES May 6

The Southern Astronomer No.68 – May 2014 All times are expressed as Universal (UT) and can be considered the same as GMT (BST minus 1 hour)

Lunar and planetary visibility mid-month

A close look at the visibility chart for May (above) shows that the period of true 'night' is actually a two hour period – an hour or so either side of midnight and true night is still yet to get shorter over the next few weeks. Sunspot activity increased on the Sun during April – lots of sunspot groups yet, they were all small groups, or at least smaller than we would expect during a 'normal' maximum. However the Sun can still show quite some activity (below).

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Active regions 2036 and 2037 (upper) observed on April 16

Brian States observed the Sun on all 31 days in March – a well done there! The average relative daily sunspot number for the month was 98. An active month. In May the calendar and lunar month are almost in synchronisation – new Moon occurred on April 29; first quarter is on May 7 with Full occurring on May 14 etc. Try and watch for the nightly changes as the lunar terminator (the line between the day and night) moves across the face of the Moon and notice the changes that occur in various features. Even over the space of several hours, shadows of lunar features will noticeably shorten as the sun rises over the lunar surface. Observing Notes continued

Mercury is visible in the evening sky at -0.6m and May is probably the best time to see it in

The Southern Astronomer No.68 – May 2014

FOR THE BEGINNER: ANGULAR MEASUREMENTS When we look at objects in the sky and need to describe their positions relative to other objects in the sky we use the degree(°).

the evening this side of the summer. Its apparent size in a telescope is 6-arc seconds and mid-May the planet will be 63% illuminated. Observers have reported it as having a pink hue – undoubtedly the effects of our atmosphere. Those with moderate to large telescopes may like to try and see faint markings (albedo features) on the disk.

The degree is then subdivided – the first is the arc-minute (') of which there are 60 (60 arcminutes equals a degree); and then finally into arc-seconds (“). As with the measurement of time (which these are sometimes confused with) there are sixty-seconds to a minute and sixty-minutes to a degree. The Full Moon measures (approximately) 30minutes or half a degree.

Albedo features on Mercury observed by Richard Baum in 1952 (left) and 1953 (right)

Venus remains an early morning object rising an hour or so before the Sun – a good eastern horizon maybe needed though some observers have, using setting circles or go-to mounts have been able to observe the planet after sunrise. The close proximity of the planet to the Sun would make this very difficult and dangerous and is not something undertaken by someone unless familiar with this technique. Mars, Jupiter and Saturn are the objects to observe in the evening sky from dusk onwards. Some details for Mars in May appear on the front page. Now past its opposition it will gradually get smaller in the eyepiece – its angular diameter ranges from 14-arc seconds on May 1 to 12-arc seconds on May 31. Do not let this however put you off. Mars is an interesting object to look at even if low in the sky and subject to the boiling turmoil of atmospheric turbulence. On a good night when the seeing is good (the stars do not twinkle rapidly) a moderate to large telescope will show the surface detail of the planet. Imaging Mars through a telescope can also produce satisfying results as well. Jupiter is now heading very much westward in the evening but is still worth looking at and make the most of its high declination during this time. After this month, it begins to fade into the twilight and this month also sees the last of the GRS transit time predictions (next page). Observations of the planet over the last few months have shown the GRS to have a pale collar around it with the Great Red Spot actually having an dark orange hue.

Use your hand for approximating angular distances

Watching Jupiter's four bright satellites moving around their primary night after night is also fascinating. April 9, 2014 © Brian Halls

Observing Notes continued

The Southern Astronomer No.68 – May 2014 The ringed planet Saturn begins to make an appearance in the evening sky during the month as it comes to opposition on May 10. Its angular diameter is a little over 18-arc seconds and it shines at 0.1m in the constellation of Libra. The planet remains low in the southern sky but, if you have had a chance to see the markings of Mars, the rings of Saturn will be visible, tilted by 22° towards us. The rings are clearly visible in small telescopes or even a powerful pair of binoculars, so are well worth looking at. Due to the lack of power in his telescope Galileo, when he first observed the planet in 1610 could not clearly define the rings. The rings were very much face on as they are now, and in his telescope the lobes of the rings appeared as two smaller planets either side of the main body. It was down to Christiaan Huygens in 1655 to define them as a ring structure surrounding the planet but, he believed them to be a solid body, something that James ClerkMaxwell disproved mathematically in the nineteenth century. The inner portion of the rings lay some 6 700 kilometres from the planet body while the outer portion are about 121 000 km from the planet; yet present estimates put the average thickness of the rings to about 20 – 30 metres!

Transits Times of the Great Red Spot (GRS) of Jupiter – best views from UK May 2: 23:31;3: 19:23; 5: 21:02; 7: 22:41; 8: 18:33; 10: 20:12; 12: 21:51; 13: 17:43; 14:23:30; 15: 19:22; 17: 21:01; 19: 22:41; 20: 18:32; 22: 20:11; 24: 21:51; 26: 23:30; 27: 19:22; 29: 21:01; 31: 2:40 All times shown are in UT Reproduced courtesy of Sky Publishing The GRS will be well placed for observing 50 minutes or so either side of the times given.

SATURN: WEIRD FACTS

A recent discovery announced the probable formation of a small moon (nicknamed 'Peggy') at the edge of the outer portion of the ring. There are at the moment 62 known satellites of Saturn – this one may be the next. Our own Moon may very well have formed the same way from the ring of debris that was created by the possible impact of proto-earth and another large body in the early years of the solar system formation. Peggy is the bright spot at the edge of the ring © NASA/JPL

(See 'Sleepy Satellite?' page 5)

Saturn is the last of the six planets known to the ancients. Depicted as an old bearded man in GrecoRoman mythology he is associated with the passing of time. To the Greeks he was Cronos and the characters Greek name is conflated with the Greek word for time – chronos from where we get our word for time pieces (e.g. chronometer). Our own 'Old Father Time' figure who appears with a scythe at years end is quite probably a modern interpretation of the character. The Roman feast of Saturnalia held close to the winter solstice has many of its elements carried over into the modern Christmas. The week day Saturday is named after this character.

Observing Notes continued

The Southern Astronomer No.68 – May 2014 There are no really bright Comets though there is a new comet that might be of interest - C/2014 E2 (Jacques). It is, as we go to press, about 9m and is visible in the constellation of Monoceros during May – the drawback here of course is that the constellation is dipping into the sunset in the west. We have only to mid-May before it disappears from view.

C/2014 E2 This comet was discovered by the Brazilian astronomers Cristóvão Jacques Lage de Faria, Eduardo Pimentel and João Ribeiro de Barros on the night of 13 March 2014. The telescope used was 0.45-metre instrument at the Southern Observatory for Near Earth Asteroids Research (SONEAR), located near Oliveira, Minas Gerais, Brazil.

Present predictions indicate that it will be a bright binocular/telescopic object visible in the morning sky from late July – magnitudes of about 7 are mentioned. But this will only happen if the comet passes by the Sun safely – and this is the dangerous bit for any comet as anyone who can remember the hype around ISON at the end of last year. We will be hearing more about C/2014 E2 in the future, no doubt.

WHAT'S IN A NAME? The most famous comet is P1/Halley. The P indicates that the comet is a periodic comet – that is, one that has predictable short term reappearances and the '1' indicates it is the first on the list. But how do you pronounce Halley? Sir Patrick Moore was very much in favour of pronouncing it – certainly in his later years – as haw-lee. There are many who remember perhaps that he used to pronounce it hal-lay (with an emphasis on the lay) but he would never, ever, pronounce it hay-lee as “that was the chap that sang Rock Around The Clock with his Comets.”

The position of C/2014 E2 at about 20.40UT near the beginning of May

Graphic by Stellarium

STELLAR & DEEP SKY If you are planning to look out for Polaris this month even if you do not have an equatorial mount that you want to align, give a thought for the small and overlooked constellation that it is the brightest star of – Ursa Minor (The Small Bear). The Small Bear is devoid of any deep sky objects but the stars are of interest. Firstly they are range from 2m, 3m, 4m and 5m and are thus a good guide to the urban dweller to determine the magnitude stars that are visible.

Polaris (α Umi) is a 2.02m yellow-white supergiant while β Umi (Kochab) is a 2.07m orange giant star. γ Umi (Pherkad) is 3m and a white supergiant. The fourth brightest star is δ Umi (Yildun) which is a white dwarf star and comes in at 4.3m. ζ Umi glories in the name of Akhfa al Farkadain and translates as the “dimmer of the two calves”- a referance to the Arabic depiction of Ursa Minor in their sky lore. It has the same magnitude as Yildun and is also a white star. Finally we have η Umi (Alasco) which is 4.9m and a yellow-white star. Alasco is about 97 light years from Earth and is the nearest while the furthest of the stars mentioned above is Pherkad which lies about 480 light years away – so we are seeing light (the speed of light of course being the fastest thing in the universe) that left Pherkad at about the time HenryVIII was wooing Anne Boleyn, the rather dodgy Sir Thomas More was being confined to the Tower of London and Jacques Cartier was making discoveries in North America.

The Southern Astronomer No.68 – May 2014 Observing Notes concluded

NOCTILUCENT CLOUD TIME Noctilucent Clouds (NLC) are a phenomenon that appears to occur from mid May through to the end of August. Though not an astronomical subject they are something that many amateur astronomers like to observe. NLC AND GLOBAL WARMING There are no records of NLC being observed before the late nineteenth century. This has lead some to claim that the appearance of NLC are the results of industrialisation and are therefore a sign of man made effects on global warming. It is believed that dust particles in high altitudes – dust, possibly being meteoric or even industrial in origin (which now appears to be the favoured theory) is coated with fine ice crystals. Under normal conditions thermal radiation from Earth would make its way into high altitudes and keep this area of the upper atmosphere 'warm'. NLC from Fife, Scotland © Corinne Mills

From the picture above it can be seen that NLC can be quite dramatic. They are visible from the southern UK as well. They are generally visible between latitudes 50o – 65o and can be best seen when the Sun is between 6°and 16° below the horizon, so these are a twilight phenomenon. As you can see from the picture above, the low regular weather clouds are dark silhouettes, while the tenuous NLC – which are much higher in the atmosphere - are illuminated by sunlight and have the distinctive electric-blue look. They are the highest clouds in Earth's atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometres (47 to 53 mi). They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earth's shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon; there is no record of their observation before 1885. There appears to be structure in these clouds and these have been categorised into types and groups. Information can be found at: http://www.nightskyhunter.com/Noctilucent Clouds.html Observing these may be a bit of a challenge but may be worthwhile. The best place to look for them is to look north during the twilight period when the Sun is below the horizon but not when it is dark. This may be late evening after sunset or early morning before sunrise. Naturally a good northern horizon is best – a northern view from the downs would be advantageous. A lot depends on the seeing, and weather conditions and of course the more normal tropospheric clouds. Occasionally high latitude cirrus cloud which can be bright in the twilight sky is mistaken for NLC – these are still too close to the ground! Good NLC hunting and don't forget to send any pictures you may capture in to us.

The argument is that greenhouse gasses are blocking this escaping heat from getting into these regions and thus allowing ice crystals to form where they would not otherwise under normal conditions. Because of the global warming implications, there is a lot of ongoing study concerning the sources, causes and mechanisms behind the phenomena. The Aurora Observing Section of the British Astronomical Association keep records of observations of NLC and more information for this may be found at: http://www.britastro.org/aurora/

The Southern Astronomer No.68 – May 2014

Image by Stellarium

The sky from Sussex at around 21.30 UT (22.30 BST) on May 15 Contributions – written articles (preferably word processed), photographs or letters to the editor for the June issue should be in by May 16 and sent to the editor at the contact address: editor@worthingastronomers.org.uk Detailed occultation predictions and other data 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.) If you no longer wish to subscribe to the group and receive newsletters and other information, please send an email (to the address above) with Unsubscribe in the subject line; we do not want our stuff to end up like spam littering your inbox. Volunteers are always welcome: if you want to find out more, call 01903 521205 or drop us a line at the e-mail address above. If you like the newsletter or its content please feel free to distribute it to anyone you know who might be interested. Content is subject to copyright to the group and/or the individuals whose images or articles are used.