The Southern Astronomer No.78 – March 2015
SOUTHERN ASTRONOMER THE
MONTHLY MAGAZINE OF WORTHING ASTRONOMERS & WORTHING SKYWATCHERS
Coming Soon: Deep Partial Solar Eclipse March 20, 2015 1
The Southern Astronomer No.78 – March 2015
Astronomy Meetings The groups listed below begin their meetings at 19.30hrs Worthing Astronomers (WA) meet on the first Friday of the month, every two months (February, April, June, August, October and December) at Goring URC, corner of Shaftesbury Avenue and Barrington Road, Worthing, BN12 4EA. Admission £3.
This Issue Diary, listings and information The One to Watch This Month: Partial Solar Eclipse Safe Solar Observing–Workshop report 6th February Messier Marathon Time – preview for end of March Sky Notes for March- Plato, Jupiter weather etc.
WA members will be made welcome at the above groups. More monthly details in the Quick View Diary, page two. Worthing Astronomers is a free to join society with a membership of over 370 persons, all sharing an interest of Astronomy. With the aid of this newsletter, website, social media, 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.
this page p3 p4 p5 p7
QUICK VIEW ASTRO EVENTS DIARY
March
All times shown are Universal Time (UT = GMT = BST minus 1 hour)
Adur AS (AAS) meet at Southwick Christian Community Church, 1-5 Roman Crescent, Southwick BN42 4TY, first Monday of the month. Admission: £5 for guests, £3 for members. WA and AAS venues have off road parking facilities and grounds adjacent for setting up telescopes when conditions allow.
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For WA and AAS details, see side bar on left
1 2 3 4 5 13 20 27 29 31
Sunrise 0648h : Sunset 1743h Start of meteorological spring AAS: Guest Speaker, Dr David Whitehouse; “Journey to the Centre of the Earth” Jupiter 5.2N of Moon (04h) Venus 0.1°N of Uranus (18.7h) Moon at apogee (furthest from the Earth) (07h) Full Moon (18h) Moon: Last Quarter (17h) New Moon (09h); partial solar eclipse from Worthing Spring (Vernal) Equinox – astronomical spring begins (22h) Moon: First Quarter (07h) Seafront Observing Evening – 19.00 onwards: check updates on Facebook and WA website British Summer Time begins (02h) Sunrise 0542h : Sunset 1834h
CONTRIBUTIONS AND UNSUBSCRIBE Contributions – written articles (preferably word processed in .txt, .doc or .odt format), photographs or letters to the editor for the April issue should be in by March 15 and sent to the editor at the contact address: editor@worthingastronomers.org.uk If you no longer wish to subscribe to the group and cancel newsletters and other information, please send an email to: info@worthingastronomers.org.uk with 'Unsubscribe' in the subject line; we do not want our stuff to end up like spam littering your in-box. 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.
Cover Pictures: Top picture, extent of totality and partial phases of the March 20 eclipse. Upper left: The Sun in Partial Eclipse. Image by Jan Halls. Lower right: Observing the Sun with a Lunt Halpha telescope by Steve Bassett
Lunar phases . March 2015
PUBLIC LIABILITY INSURANCE This is the time of year when we have to think about what we are going to do observing wise, both as a group and our outreach programmes with the public; coming up are a number of events that we are hoping to involve ourselves with such as Global Astronomy Month in April, our numerous seafront observing nights which are popular with both the group members and public alike and later in the year, International Moon Observing Night. To do events such as these, a requirement of the Worthing Borough Council is for groups like ourselves to have a Public Liability Insurance – so the Council don't get sued themselves when someone falls off one of their ornamental rocks at Splashpoint and hurts themselves for example (and a reason why we have stopped using Splashpoint!) Our present insurance which we get through the Federation of Astronomical Societies expires at the end of March so we need to ask for donations which we can use to put towards getting the necessary insurances. Cheques and cash gratefully accepted - all donations will be receipted.
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The Southern Astronomer No.78 – March 2015 PARTIAL ECLIPSE WORTHING TIME TABLE First Contact (Moon begins to cross solar disk): 08h 23m 33s Maximum Cover: 09h 29m 38s (~86%) Last Contact (Moon leaves solar disk): 10h 39m 47s
PHOTOGRAPHING THE SUN Shutter Speed 1/500 1/250 1/125 1/60
f-number 8 11 16 22
The table assumes a ND5 filter is being used and an ISO setting of 100 'film' speed
Optical system and weather conditions should be allowed for. It is recommended that test shots prior to the eclipse should be made.
Jan and Brian will have the Cokeham Observatory open the morning of the partial eclipse from about 8.15 – weather permitting – for members, their family and friends who are able, © Brian Halls to pop along and watch the progress of the event.
THE ONE TO LOOK OUT FOR THIS MONTH:
Call 01903 521205 for details.
PARTIAL SOLAR ECLIPSE The total eclipse of the Sun that occurs during the morning of March 20 is a good opportunity to see one of natures wonders. Totality – that is when the Moon completely covers the Sun - occurs on a thin track in the North Atlantic/ Arctic Ocean, roughly half way between the northern end of the British mainland and Iceland.
small suitable filter at the ready for naked-eye observing. A suitable dark filter is a #14 grade welder glass. This gives the Sun a yellow-green cast but is safe for non-telescopic use (see picture below).
If you are not on that track, the Moon will not cover the Sun and you will not see totality. Some of our members are lucky to be going though for those of us almost a thousand miles south who will not be there, we will be able to enjoy the event as a partial solar eclipse.
Pinhole projecting a partial eclipse
Never, ever use; old film negatives, CD/DVD disks, metalized-plastic food wrappings or the such – they may dim the image but permanent damage to your eyesight will result as they will pass solar radiation onto your eyes.
Because we are not far from the totality track, the Sun will be covered quite considerably (86% from southern Britain). These are not as rare as you might think. In 1999 there was the total eclipse that clipped Cornwall, with a totality track that passed across Safely viewing the Sun through #14welder glass the English Channel and then to the continent. The amount of partial in Worthing then was about 98% A safe alternative is a pair of 'eclipse' glasses – enough to make the alteration to light level cardboard spectacles with a metallized-plastic foil noticeable. such as Baader Planetarium Astrosolar Safety Film to look through. Eclipse specs can be purchased at In September 2005, an annular eclipse of the Sun a reasonable cost and are worn as below. took place over Spain and again, we saw under half the Sun covered by the Moon (top picture). This Baader film can also be purchased as “THROUGH A GLASS, DARKLY” an A4 size sheet from which your own solar Observing the partial phase of the eclipse is an filters can be made. interesting way to see one of natures greatest phenomena, but some care must be taken. A pin hole camera is another way to observe The Sun is a source of great heat as well as the progress of an light. Light can be reduced using filters -but not so eclipse – or a kitchen some of the eye damaging radiation that comes Safety specs in use colander/ strainer or from the Sun. Anyone anticipating observing the event during breaks at work could do no worse than have a
© Jan Halls
other utensil can be used to project dozens of pinhole images of the Sun onto a piece of white card (top, next column).
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If purchasing a pair of eclipse 'glasses' always follow the instructions carefully – different manufacturers use different types of safe material but their recommendations should be followed. Baader Astro Solar eclipse glasses are available and cost about £3.90 a pair. A list of telescopic methods for observing the Sun (not only at eclipse time) follows on this article.
The Southern Astronomer No.78 – March 2015
WORKSHOP REPORT: OBSERVING THE SUN SAFELY The February Workshop took place on the 6th at the usual venue, Goring United Reform Church, Cornwall Rooms.
THE WEDGE OF DARKNESS The last tool for safe solar observing is both new and old. The solar diagonal (aka Herschel Wedge) was invented in the nineteenth century by Sir John Herschel as a convenient method of observing the solar image through a telescope. They fell out of favour during the early twentieth century but they are now back and are built using modern technology.
Thirty-six members came to discover how to observe the Sun in safety – the workshop session being conducted by Brian Halls. Brian has been observing the Sun for nearly fifty years – he began as a teenager – and he said that there had been changes in the tools available to the amateur solar observer for solar observing. When he began there was only one real safe way one could observe the Sun.
Suitable only for refractors sunlight and heat passes through the telescope in much the same was as it does when solar projecting. It is in the design of the solar diagonal where the secret of its workings are.
After briefly explaining the solar effects that cause sunspots and what features an amateur would expect to see with their back-garden telescope, he went onto advise the differing and safe methods available for solar observing. The safest method (and the one espoused by Patrick Moore) is the solar projection method; this method which has been around for as long as the telescope (1609) uses the telescope to project an image of the Sun onto a piece of white-card held at a distance behind the eyepiece (below).
Light comes through the 'scope and reflects off a specially engineered wedge shaped piece of glass (from where the device gets its more common name of solar or Herschel wedge.) A commercially available Hossfield Pyramid projection box
coated, without any adverse effects to either. The SCT and Newtonian owner is not barred from safe observing of the Sun however. A trick is to use an aperture filter. As the name implies, it fits over the front (or aperture end) of a telescope blocking the glare of sunlight and blocking eye damaging heat before it gets anywhere near the optics (and your eye). Two types are available. Metal on glass and metallizedpolyester foil.
About 95% of the solar heat passes through the back of the wedge and into a light trap or heat-sink. The image of the Sun is reflected upwards at 45° into the eyepiece. The glass wedge absorbs about 4-5% of the heat while any heat which is still left is captured and blocked by a ND 5 filter which come already fitted to the diagonal assembly. A secondary filter (ND 3 or polarizers) is recommended to be fitted to the eyepiece to reduce further any solar glare.
If looked after the solar-diagonal will give a life times service. Like the polyester-foil used in aperture filters, the image in the eyepiece shows The metal on glass type are expensive but if looked the Sun in white; this allows the use of coloured eyepiece filters to view the Sun in much the same after, will give many years reliable service. They way as one would do with the planets. give the image of the Sun an orange tint which brings out detail in sunspots. An orange filter will enhance sunspot detail; a blue filter will show off the lighter tendrils of faculæ seen The plastic foil type is cheaper – it can come already made in an adapter that fits tightly over the around sunspots, while a green filter will show off the surface details of the solar granulation. front end of a 'scope – or you can buy it by the © Lee McDonald sheet and make your own filters. Both types of filter should be checked prior to use but especially so Brian uses a continuum filter which, at the There are advantages to using this – especially for the foil type as they can get damaged. If looked 540nm (nanometre) range of the spectrum gives a special events such as Mercury transits or the after it will give several years service before the green hue to the view but it enhances all the fine partial phases of solar eclipses – several people scissors, cardboard and gaffer tape come out detail in spots and the solar surface; it is even can watch the event at the same time with same again to make a replacement (see below,left). claimed by some, to smooth out some of the worse telescope. excesses of atmospheric seeing. The plastic foil (see previous article) has the Rig up some sort of contraption to hold the card advantage in giving the Sun a more natural and your hands are free to make notes or draw the white/blue tint. One word of warning. This foil solar disk and make sunspot counts – the field of comes in two types – neutral density (ND) 5.0 solar observing that Brian does. which is safe for viewing and photography ND 3.8 which is for photographic use ONLY. Of course, If you are not into DIY, there is something aperture filters can be used with refractors as well manufactured called a Hossfield Pyramid – a as SCT's and Newtonians. projection box already made for fitting to a telescope (top, next column). Plans for making such a box out of lightweight materials is available also on the world wide web. The only telescope really suitable for solar projection is the refractor. As heat is allowed into the optical path, this makes the SchmidtCassegrain (SCT's) and Newtonian reflectors unsuitable as the captured and concentrated heat will damage the optics. Never use plastic bodied eyepieces for the same reason(!!)
Solar-diagonal in operation in conjunction with 150mm refractor © Brian Halls
The general consensus is that simple eyepieces such as the Huygenian and Ramsden type are best as they are not coated or cemented – however they Home made aperture filter holder on left; commercially are difficult to find. Brian has used for several years bought one on right. The left hand filter was made to fit a Plossl eyepiece (cemented optics) which are also onto a camera telescopic zoom lens. © Brian Halls
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The next Workshop is on April 10 and it will be a Telescope & Equipment Clinic.
The Southern Astronomer No.78 – March 2015
Š Mike Williams
THE MESSIER MARATHON MOMENT 2015: WEEKEND MARCH 20/21st Late winter/early spring sees many deep sky amateur astronomers engaging in a sporting like pastime - The Messier Marathon. During the space of a few days during the spring almost all the Messier objects are (theoretically at least) visible during a single nights observing hence the term Marathon. The Messier Marathon has been popular in the USA for the past 40 years or so for the very good reason that all the Messier objects (M1 to M110) can all be seen from that continent. We UK observers are nobbled by the fact that some of the more southerly Messier objects are just below the horizon and never rise from UK latitudes. Our colleagues in the more southerly Spain, should be able to pick up all the objects through an evening. There are 11 such M-objects not visible to us in the UK for one reason or another: M6 M7 M30 M33 M54 M55 M62 M69 M70 M74 M83. To capture as many M-objects as possible the 'runners' (if we can call them that) observe from the western sky at sunset and progressively work their way eastward over the night until the first light of dawn the next morning. The most critical objects in the evening are M74 and M77 - you have only a short time to observe them before they set. Fancy it? Like a real marathon a certain amount of stamina to keep going is needed through have to wait for the morning objects to rise; the night; a good location with a good skyline to start with - you don't want to waste precious
time lugging 'scopes about to get a better view of something, and like any good runner a team around you to pace yourself, and of course - good weather. On the early evening of March 21 the Moon will be just over 32 hours old and thus a thin sliver of a crescent setting soon after the Sun so, moonlight for much of the night will not be a problem.
around 5.30 - 6pm and run through until dawn the following morning (weather permitting obviously) Attached is a photo containing all 110 Messier objects. So my question to you all is, who's interested????
An added feature for some members will be to image as many Messier objects as possible – to mix track and field metaphors, the bar has been set high for those who want to image as well as observe. So! Where are we go to observe from? As we go to press, plans are for either Kithurst Hill or Nepcote Green. If you are interested and have any preferences then drop a line to Mike Williams at: mikeywill@btinternet.com
As usual, the session is subject to weather conditions as well as the preferences of those Mike writes: The New Moon will occur on March wanting to have a go, so either the Friday night 20, and will provide the best opportunity for a (20/21st) or the Saturday night (21/22nd) will be Messier Marathon on the weekend of March 20-22 used. (Fri / Sun morning), 2015. At this date, there will Of course the evening is also open to anyone be a considerably good opportunity to hunt down who just wants to come and long and have a look many of the 110 Messier Objects in one night. and who may not intend to stay the entire night. This is open to all and can be done as a visual The full list of Messier objects to be observed, in exercise or imaging, I need to put more details order, is on the next page and is based together before making this a full group event and upon a list that appears in Don Machholz, Messier would welcome any feedback from anyone Marathon Observer's Guide. interested in taking part, start time would be from
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The Southern Astronomer No.78 – March 2015 A list of all Messier objects in order of observing during an evening 1 2 3 4 5 6* 7* 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30* 31 32 33* 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54* 55* 56 57 58 59 60 61 62* 63 64 65 66 67 68 69* 70* 71 72 73 74* 75 76 77
M
NGC
Const
Type
M77 M74 M33 M31 M32 M110 M52 M103 M76 M34 M45 M79 M42 M43 M78 M1 M35 M37 M36 M38 M41 M93 M47 M46 M50 M48 M44 M67 M95 M96 M105 M65 M66 M81 M82 M97 M108 M109 M40 M106 M94 M63 M51 M101 M102 M53 M64 M3 M98 M99 M100 M85 M84 M86 M87 M89 M90 M88 M91 M58 M59 M60 M49 M61 M104 M68 M83 M5 M13 M92 M57 M56 M29 M39 M27 M71 M107
1068 628 598 224 221 205 7654 581 650 1039 1904 1976 1982 2068 1952 2168 2099 1960 1912 2287 2447 2422 2437 2323 2548 2632 2682 3351 3368 3379 3623 3627 3031 3034 3587 3556 3992 Win4 4258 4736 5055 5194 5457 5866 5024 4826 5272 4192 4254 4321 4382 4374 4406 4486 4552 4569 4501 4548 4579 4621 4649 4472 4303 4594 4590 5236 5904 6205 6341 6720 6779 6913 7092 6853 6838 6171
Cet Tri And And And And Cas Cas Per Per Tau Lep Ori Ori Ori Tau Gem Aur Aur Aur Cma Pup Pup Pup Mon Hya Cnc Cnc Leo Leo Leo Leo Leo UMa UMa UMa UMa UMa UMa CVn CVn CVn CVn UMa Dra Com Com CVn Com Com Com Com Vir Vir Vir Vir Vir Com Com Vir Vir Vir Vir Vir Vir Hya Hya Ser Her Her Lyr Lyr Cyg Cyg Vul Sge Oph
5 5 5 5 6 6 1 1 3 1 1 2 4 4 4 9 1 1 1 1 1 1 1 1 1 1 1 1 5 5 6 5 5 5 7 3 5 5 C 5 5 5 5 5 8 2 5 2 5 5 5 8 8 8 6 6 5 5 5 5 6 6 6 5 5 2 5 2 2 2 3 2 1 1 3 2 2
RA 02 42.7 01 36.7 01 33.9 00 42.7 00 42.7 00 40.4 23 24.2 01 33.2 01 42.4 02 42.0 03 47.0 05 24.5 05 35.4 05 35.6 05 46.7 05 34.5 06 08.9 05 52.4 05 36.1 05 28.4 06 46.0 07 44.6 07 36.6 07 41.8 07 03.2 08 13.8 08 40.1 08 50.4 10 44.0 10 46.8 10 47.8 11 18.9 11 20.2 09 55.6 09 55.8 11 14.8 11 11.5 11 57.6 12 22.4 12 19.0 12 50.9 13 15.8 13 29.9 14 03.2 15 06.5 13 12.9 12 56.7 13 42.2 12 13.8 12 18.8 12 22.9 12 25.4 12 25.1 12 26.2 12 30.8 12 35.7 12 36.8 12 32.0 12 35.4 12 37.7 12 42.0 12 43.7 12 29.8 12 21.9 12 40.0 12 39.5 13 37.0 15 18.6 16 41.7 17 17.1 18 53.6 19 16.6 20 23.9 21 32.2 19 59.6 19 53.8 16 32.5
Dec -00 01 +15 47 +30 39 +41 16 +40 52 +41 41 +61 35 +60 42 +51 34 +42 47 +24 07 -24 33 -05 27 -05 16 +00 03 +22 01 +24 20 +32 33 +34 08 +35 50 -20 44 -23 52 -14 30 -14 49 -08 20 -05 48 +19 59 +11 49 +11 42 +11 49 +12 35 +13 05 +12 59 +69 04 +69 41 +55 01 +55 40 +53 23 +58 05 +47 18 +41 07 +42 02 +47 12 +54 21 +55 46 +18 10 +21 41 +28 23 +14 54 +14 25 +15 49 +18 11 +12 53 +12 57 +12 24 +12 33 +13 10 +14 25 +14 30 +11 49 +11 39 +11 33 +08 00 +04 28 -11 37 -26 45 -29 52 +02 05 +36 28 +43 08 +33 02 +30 11 +38 32 +48 26 +22 43 +18 47 -13 03
Mag 8.9 9.4 5.7 3.4 8.1 8.5 7.3 7.4 10.1 5.5 1.6 7.7 4.0 9.0 8.3 8.4 5.3 6.2 6.3 7.4 4.6 6.0 5.2 6.0 6.3 5.5 3.7 6.1 9.7 9.2 9.3 9.3 8.9 6.9 8.4 9.9 10.0 9.8 8.4 8.4 8.2 8.6 8.4 7.9 9.9 7.6 8.5 6.2 10.1 9.9 9.3 9.1 9.1 8.9 8.6 9.6 9.5 9.6 10.2 9.7 9.6 8.8 8.4 9.7 8.0 7.8 7.6 5.6 5.8 6.4 8.8 8.3 7.1 4.6 7.4 8.2 7.9
Size(')
78 79 80 81 82 83* 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110
7x6 10.2x9. 573x45 178x63 8x6 8.5 13.0 6.0 2.7x1.8 35.0 110.0 8.7 85x60 20x15 8x6 6x4 28.0 24.0 12.0 21.0 38.0 22.0 30.0 27.0 16.0 54.0 95.0 30.0 4.4x3.3 6x4 2.0 8x1.5 8x2.5 21x10 9x4 3.4x3.3 8x1 7x4 0.8 19x8 7x3 10x6 11x7 22.0 5.2x2.3 12.6 9.3x5.4 16.2 9.5x3.2 5.4x4.8 7x6 7.1x5.2 5.0 7.5x5.5 7.0 4.0 9.5x4.5 7x4 5.4x4.4 5.5x4.5 5x3.5 7x6 9x7.5 6x5.5 9x4 12.0 11x10 17.4 16.6 11.2 1.4x1.0 7.1 7.0 32.0 8.0x5.7 7.2 10.0
M
NGC
Const
Type
RA
Dec
Mag
M12 M10 M14 M9 M4 M80 M19 M62 M6 M7 M11 M26 M16 M17 M18 M24 M25 M23 M21 M20 M8 M28 M22 M69 M70 M54 M55 M75 M15 M2 M72 M73 M30
6218 6254 6402 6333 6121 6093 6273 6266 6405 6475 6705 6694 6611 6618 6613 6603 I4725 6494 6531 6514 6523 6626 6656 6637 6681 6715 6809 6864 7078 7089 6981 6994 7099
Oph Oph Oph Oph Sco Sco Oph Oph Sco Sct Sct Sct Ser Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Sgr Peg Aqr Aqr Aqr Cap
2 2 2 2 2 2 2 2 1 1 1 1 1 4 1 B 1 1 1 4 4 2 2 2 2 2 2 2 2 2 2 A 2
16 47.2 16 57.1 17 37.6 17 19.2 16 23.6 16 17.0 17 02.6 17 01.2 17 40.1 17 53.9 18 51.1 18 45.2 18 18.8 18 20.8 18 19.9 18 16.9 18 31.6 17 56.8 18 04.6 18 02.6 18 03.8 18 24.5 18 36.4 18 31.4 18 43.2 18 55.1 19 40.0 20 06.1 21 30.0 21 33.5 20 53.5 20 58.9 21 40.4
-01 57 -04 06 -03 15 -18 31 -26 32 -22 59 -26 16 -30 07 -32 13 -34 49 -06 16 -09 24 -13 47 -16 11 -17 08 -18 29 -19 15 -19 01 -22 30 -23 02 -24 23 -24 52 -23 54 -32 21 -32 18 -30 29 -30 58 -21 55 +1210 -00 49 -12 32 -12 38 -23 11
6.7 6.6 7.6 7.7 5.6 7.3 6.8 6.5 5.3 4.1 6.3 8.0 6.4 7.0 7.5 4.6 6.5 6.9 6.5 9.0 6.0 6.8 5.1 7.6 7.9 7.6 6.3 8.5 6.2 6.5 9.3 9.0 7.2
Size(') 14.5 15.1 11.7 9.3 26.3 8.9 13.5 14.1 25.0 80.0 14.0 15.0 7.0 11.0 9.0 90 40.0 27.0 13.0 28.0 90x40 11.2 24.0 7.1 7.8 9.1 19.0 6.0 12.3 12.9 5.9 2.8 11.0
* Not visible from UK Types: 1=Open Cluster, 2=Globular Cluster, 3=Planetary Nebula, 4=Diffuse Nebula, 5=Spiral Galaxy, 6=Elliptical Galaxy, 7=Irregular Galaxy, 8=Lenticular (S0) Galaxy, 9=Supernova Remnant, A=Group or Asterism of Four stars, B=Star Cloud, C=Double Star
STARGAZING ON THE PROM:
SEAFRONT OBSERVING EVENING MARCH 27 We hope to meet once more on the seafront just to the east of the junction of Grand Avenue on Friday evening, March 27. This is a an early kick-off to Global Astronomy month that occurs in April. The Moon will be just past first quarter and there will be lots of detail to share with your colleagues in the group and of course members of the public. Volunteers are of course, always welcome – if you have a telescope please feel free to bring it along. The Moon, Venus, Jupiter and for those 'die-hards' who may want to stargaze into the wee hours, there will be Saturn as well as many deep sky objects that will be worth looking at. Further details to follow – check your mail box, Facebook and the society website. For more details contact steve_bassett@hotmail.com or if you are on Facebook check out Worthing Skywatchers. As details are confirmed an update will be posted out to members via the email.
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The Southern Astronomer No.78 – March 2015
OBSERVING NOTES March All times are expressed as Universal (UT) and can be considered the same as GMT (BST minus 1 hour). Information, unless otherwise stated is for the 15th of the month The Sun is now rising earlier and setting much later as time progresses; there is about a 50 minutes difference in the rises and sets between the start and end of the month. As dusk falls, Jupiter is high and bright in the eastern sky and though now well past opposition is still a fascinating object to observe, either through binoculars or a telescope, while Venus is a bright object in the western evening sky. Both objects will be around for some months yet.
Visibility of Moon and planets, including sunrises and sets, mid-month
The Sun is an ever changing object – sunspots can come and go quite rapidly or change their appearance as the magnetic fields that help create them alter. Sometimes changes are subtle while others can occur over the space of a short few minutes. A large filament over 1 million kilometres long appeared in early February. A filament is created when gaseous material from the solar surface (photosphere) is hoisted up above the surface by local magnetic fields. A filament is another name for prominence which is used to describe filaments when seen in profile at the edges of the Sun.
Solar data for mid-month
This particular one observed on February 8 by several members using h-alpha telescopes, appeared to emanate from sunspot group, AR 2280 (the bright white area to the right of the filament in central picture, left). This filament was certainly active – the three frames at the bottom show progress of filamentary material in the space of about 7 minutes. The large filament of early February (3 pane mosaic)
© Brian Halls
Based upon the observations from members, the average daily sunspot number for January was 78.1; Brian States got to observe on 24 days during the month. Just one more reminder (if one is needed). Take great care in looking at the Sun during the partial eclipse on the 20th. If you can't be sure, then do not. The BBC Stargazing Live Team will be back during the week preceding the eclipse where hints on how to observe the eclipse and why it happens will be broadcast as well, of course, other astronomy matters.
Detail of changes in filament structure over a 7 minute period
© Brian Halls
The filament images above were made using a dedicated solar telescope that looks at the Sun at a particular wavelength of light – the hydrogen alpha region at 656.28 nanometres. Filaments and prominences observed are invisible in the normal 'white-light' we see with our eyes as the glare from the Sun swamps it out. Special filters balance this and we can see the results similar to the above.
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On March 4th volunteers will be speaking about the partial eclipse to school children at Sompting Village Primary School, and if it is clear, will have telescopes at the ready to show children, parents and staff views of the Moon, Jupiter and other objects.
The Southern Astronomer No.78 – March 2015 Observing Notes continued
by the astronomer Riccioli), has never had a single drop of moisture fall upon it. It is known as a walled plain and dates from a lunar geological period known as the Upper Imbrian Period, the crater/lunar feature forming period that occurred between 3.2 and 3.8 billion years ago.
MOON During the evening of March 28 try and get a look at the Moon at around 18.01UT. Why such a precise time? The Moon will just be past first quarter (half Moon) and the Sun is rising above the eastern lunar horizon. The morning terminator is beginning to illuminate lunar features.
Though we see the crater looking a little elliptical, it is actually circular and measure about 101x101km in size with the highest walls of the feature rising about 2000m above the local floor.
As the Sun does this, shadows and light can mix and create illusions that might baffle briefly, the earth-bound-telescope using astronomer.
Even if you don't get a chance to see Plato at the precise moment as described, give it a look at other times as the sunrises and sets across it and take in the majestic spires of the crater walls as they are thrown across the floor of the crater. When Plato is under full Sun can you see shading on its floor?
One such illusion occurs in the crater Plato. For a brief few minutes the rising sun will highlight a bright patch in otherwise dark surroundings.
For anyone, a good test of optics and seeing is the ability to see the At first glance it looks as if there is a vapour cloud on the floor of the small craters that sit on the floor of Plato. crater – something of course that is totally impossible! This is what PLANETS Brian Halls observed on Halloween Night, 2014 with a 200mm SCT. Mid-month, Mercury will not be visible in the evening rising shortly before the Sun in the morning. Despite the planets' renown ability for He reported this observation to Dr Tony Cook, transient lunar phenomena (TLP) investigator at the BAA lunar section. Tony takes speedily orbiting the Sun, it is poorly placed this month. up the story: Between Mercury and Earth, Venus is now getting quite bright in the evening sky, shining at -3.9m. Its phase is still similar in “The effect is probably the result of the eastern rim of [a] double floor craterlet, catching sunlight above the floor area, which in turn, appearance to a gibbous Moon, its not due to reach its half phase makes it noticeably brighter than the Plato’s floor. The ‘Halls Effect’ until early June. Seeing conditions have been a problem during the late winter with atmospheric rippling causing distortion to the image. is quite spectacular and short lived, and I have generated a set of A yellow filter (W15 for example) helps. With spring now beginning predictions for the next few years... if any of our budding high resolution photographers would like to have a go at capturing this.” and good seeing, dusky patches can be just made out on the globe of the planet – these are markings in the volatile and poisonous Not a TLP, so no prizes but perhaps one more piece of a jigsaw that clouds that shroud the planet. has seen reports of misty patches being observed on the floor of the After its close approach to Mars last month, it will be the turn of crater over the last 150 years or so. Uranus to pass close to Venus on March 4 at just before 19h UT. Would you like to have a go and see if you can capture this? Brian At the end of February, both Venus and Mars appeared close to was imaging Plato in an attempt to capture the small craterlets on its floor and he did so capturing at the very right time a bright patch each other. This line of site effect is now over. Mars remains low in the south-west after sunset. At only 4”of arc wide, the planet is really made an appearance (see picture below). beyond the range of most amateur instruments. Mars next comes to opposition in late May 2016 when it will be low in the south, when its The next best time to capture this event after this month, might be angular diameter will be about 18” of arc. on the early evening of November 19 2015, at 17.30UT. Reigning supreme in the evening sky is Jupiter.
Plato and bright patch, Halloween Night, 2014
GRS Transits 01/2015 @ 19:21 UT 03/2015 @ 21:00 UT 05/2015 @ 02:46 UT 05/2015 @ 22:38 UT 06/2015 @ 18:29 UT 08/2015 @ 00:16 UT 08/2015 @ 20:07 UT 10/2015 @ 01:54 UT 10/2015 @ 21:46 UT 12/2015 @ 23:24 UT 13/2015 @ 19:15 UT 15/2015 @ 01:02 UT 15/2015 @ 20:53 UT 17/2015 @ 22:32 UT 18/2015 @ 18:23 UT 20/2015 @ 00:10 UT 20/2015 @ 20:01 UT 22/2015 @ 21:40 UT 24/2015 @ 23:18 UT 25/2015 @ 19:10 UT 27/2015 @ 00:57 UT 27/2015 @ 20:48 UT 29/2015 @ 22:27 UT 30/2015 @ 18:18 UT
© Brian Halls
On an early moon map, created by the astronomer Hevelius during the early seventeenth century, he named the feature we know today as Plato, The Great Black Lake. The misty patches observed by many astronomers, including Patrick Moore in 1972 would be an appropriate feature to see over a lake at sunrise, but Plato (named
The GRS will be well placed 50 minutes either side of these times.
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On the left is a table of the transit times of the Great Red Spot (GRS) during the month when it is observable in the sky. Even in a small telescope the planet is a magnificent object. With a moderate to large instrument, many of the features can be made out. Certainly, members of the group have produced some stunning images of the planet since it came to opposition in early February. The satellites of the planet are also well placed for observing as they interact with each other – eclipsing, shadow transiting and occulting each other as the earth passes through the plane of their orbit around Jupiter. This effect will last until the summer when Earth passes through the plane and out over the ecliptic.
The Southern Astronomer No.78 – March 2015 Observing Notes continued
The two Jupiter images by members Stuart Hillaker (top) and Andy Li (lower) show the planet very well. The GRS is prominent and the 'eye' like feature around it is the boundaries of the Spot; it is shrinking! Cassini described the GRS in 1665; thirty years earlier Riccioli also described the planet as having two large ovals about a “..seventh of the diameter of the planet..” It has even been speculated that the GRS described by Cassini is not the object we see today. It is even further suggested that the lifetime of a spot that size is 300 to 400 years. The GRS is not always red. It can be almost brick red while at other times it can be a much softer hue like salmon pink. © Stuart Hillaker
The GRS sits on the edge of two belts, the darker South Equatorial Belt (SEB) and the lighter South Temperate Belt (STB). The other belts and features are prominent as well, in both pictures. Just to the north edge of the bright Equatorial Belt (EB) dark grey/blue areas can be made out in both images. These are know as blue festoons and these are cloud features that appear on a regular basis. Both Stuart and Andy have imaged a small dark streak in the northerly bright belt – North Temperate Belt (NTB). These are known as 'barges' and again, are part of the tumultuous atmospheric conditions going on in the upper reaches of the planet. Occasionally bright white spots or ovals are observed; these are actually long lived features that lighten and darken periodically. The planet has a considerable meteorological profile and terms used in terrestrial meteorology – jet streams etc. are used to describe all manner of atmospheric disturbances in the planet.
© Andy Li
Jupiter is not the only gas giant planet visible during the night. Saturn is rising after midnight and is still best seen by either nightowls or early risers. Low in the south, a good southerly horizon is best to see the planet. It lies above the 'claws' of the constellation of Scorpius and is unmistakeable at -2.3m. The rings that surround the planet might just be visible in a pair of large binoculars. They are tilting towards us at an angle of 19° - this is less than than they were earlier in the year due to our own planet moving through the solar system. When we see the rings we are looking at the northern face of them. Though they look pretty solid they are made up of billions of small particles and the rings have differing density and widths depending on the materials that make them up. They are sufficiently thin enough for small spacecraft to pass through them with out any harm and it is even possible to (when circumstances allow) to see stars shining through them. How and why these rings occurred is unknown and still open to debate. Both Jupiter and Uranus also have ring systems around them but, these are much smaller and fainter and are much more tenuous and less grand than the ring system of Saturn.
A schematic showing the different belts (lighter and darker); all act in opposing directions. Over time, this will have the effect of the longitude of long term features visible on the planet (like the GRS) moving away from their 'mapped' positions and drifting to new locations.
Uranus is in conjunction with Venus on the 4th while outer most major planet Neptune becomes a morning object and rises a little before the Sun.
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The Southern Astronomer No.78 – March 2015 Observing Notes continued
METEORS & COMETS There are no bright meteor showers due this month. We have to wait for the Lyrids next month. Comet Lovejoy (C/2014 Q2) remains in our skies though getting fainter this process has been slower than expected and the comet is expected to remain just at the limit of naked eye visibility, 6 m.
Cassiopeia is easily recognisable as a W like figure in the sky (equally of course it can look like a M depending on where it is in the sky). Either way, it is recognisable. It lays within the boundaries of the Milky Way and on a clear dark night, and well away from any light pollution, the surrounding stars can almost envelope the distinctive shape. The star α (alpha) is known as Shedir. It is actually a binary – the brighter 2.2m star is orange while the fainter 9m star is blue. An interesting test for binoculars or small telescope.
At the beginning of March it leaves Andromeda and enters Cassiopeia. It remains in the circumpolar region of the sky – it does not set. An interesting object is γ (gamma) Cas which is a fast rotating object that periodically sheds material as it spins around. This has Mid month it is close to one of the brighter stars of the constellation, the effect of making the star appear variable as the material cast off the 2.6m star Ruchbah (δ-Cas). It remains with the 'northern queen' partly obscures the star and as it clears, the star brightens. Gamma for the remainder of the month and into April. Cas has a minimum magnitude of 3.0 and a maximum magnitude of 1.6. Ruchbah which Comet Lovejoy closely interacts with this month is also a variable star of the Algol type (see Southern Astronomer No.75). Unlike Algol itself, Ruchbah's period is about a year while variability is only about 0.1m. From the map on the left, it can be seen that Cassiopeia is rich in deep sky objects and a few are shown here. NGC 281 is commonly known as the Pac-Man Nebula after its appearance of the computer game character with its wide open mouth as seen in profile. NGC 457 (6.4m) has several names – the picturesque Dragonfly Cluster, but it is also known as the Owl Nebula, ET Cluster and, Caldwell 13. The open cluster NC225 or The Sailboat Cluster is about 7m. NGC 381 is another open cluster and was discovered in 1783 by Caroline Herschel, sister of William, and aunt of John Herschel. Caroline is often eclipsed by her more famous brother but she was a renown astronomer in her own right; not only did she help William with his observations but observed discovered several comets in her own right. She was the first woman to be awarded the Gold Medal of the Royal Astronomical Society. This 16th March sees the 266th anniversary of her birth. She died on January 8, 1848 (aged 97). Just below where NGC 129 lays, one of natures most dramatic events occurred in November 1572.
Cassiopeia: Lovejoy is in the blue cross-hairs below Ruchbah
Stellar & Deep Sky Using the whole sky chart on the opposite page (p11) you will find Cassiopeia in the northern area of sky.
A new star was seen shining in the skies. Its common name is Tycho's Star named after the astronomer who first described it and wrote a book about it. Nearby and bright supernova's are rare creatures to be observed from Earth. This one occurred at the time when many were questioning the views of the Greek philosopher Aristotle who taught that the stars were unchanging.
A supernova is a star that comes dramatically to the end of its life; nuclear processes are all but exhausted and a large star of a In mythology, she is the beautiful (and vain) Queen who boasted certain mass finding itself in such a state will collapse. We tend to about her beauty annoying one of the goddesses on Olympus – not often think of events in astronomy occurring over long periods of a great move! This led to her daughter Andromeda being offered as time, yet an exhausted star like the one described will collapse at a potential sacrifice to Posiedon, the Sea God. hypersonic speed; the result of this implosion is a massive explosion that will destroy the star completely. Andromeda was rescued in the nick of time by Perseus riding his winged steed, Pegasus. All these character, along with Laying at a distance of between 8000 to 10 000 light years from us Cassiopeia's long suffering husband Cepheus, are all northern sky there is little to observe for the amateur astronomer. constellations.
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The Southern Astronomer No.78 – March 2015
THE NIGHT SKY: March15 A view of the night sky from the Worthing area at around 21.30UT
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The Southern Astronomer No.78 – March 2015
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