THE COMET’S TALE

Newsletter of the Comet Section of the British Astronomical Association

Volume 10, No 2 (Issue 20), 2003 October

George Alcock Remembered

nickel-iron. Stones form the BAA-RAS Pro-am Particular thanks are due to majority of meteorites. Their discussion meeting Tracey and the technical staff of main components are chondrules the Open University for giving up and calcium-aluminium Milton Keynes their Saturday and interfacing all inclusions. The chondrules say the various laptops to the display something about asteroid 2003 May 10 system, to Barrie Jones of the OU formation. The CAIs formed 3 for arranging use of the facilities my before the chondrules, 4.568 and to Simon Green and John by ago. Interstellar grains are also Zarnecki for conducting the lunch present as silicon carbide and time tours. Peter Hudson also diamonds. The silicon carbide supervised visits to the newly has variable isotopic composition opened OU observatory. and therefore comes from different stars undergoing The morning session was devoted different reactions. At least 35 to meteorites and meteors, with stars contributed material. Monica Grady (Natural History Meteorites may also come from Museum) having the unenviable comets, the moon and mars. task of setting the scene. The Deserts such as the Sahara and solar system formed in a region Antarctica are good places to hunt similar to the Orion Nebula, with for meteorites. They come in asteroids being remnant various sizes - the Arizona fragments. Eros is an irregular meteorite crater was formed by an object, well-battered over 4.6 object 40 metres across and gave billion years. Pieces of asteroids a 1 km diameter crater. The fall to earth as meteorites. object that fell 65 my ago had Around 80 astronomers gathered Spectra of asteroids match those significant effects on life on earth. together on May 10 for a of meteorites and also the orbits On average one falls over the UK discussion meeting in the Open of fireballs match those of every 11 years. Falls are not University Berrill Lecture Theatre asteroids. Meterorites are cool predictable and the next one may in Milton Keynes. Although when the land, protected by a thin be over Milton Keynes! advertised as doors opening at fusion crust. There are three 10:30, early arrivals had appeared types of meteorites - irons, stones Continued on page 4 by 9:30! Fortunately Tracey and stoney-irons. Irons contain Contents Moore from the OU was there nickel and many other metals in Comet Section contacts 2 ready to welcome visitors and the trace amounts. Heat (from Section news 2 OU catering staff were already on gravitational collapse and Tales from the past 3 hand to provide refreshments. radioactive decay) allows Pro-am meeting (Cont) 4 reduction reactions similar to a Professional tales 7 Several displays were available blast furnace and metal MACE meeting 8 for inspection during the day, accumulates in the centre of the Competition winners 11 including comet drawings by asteroid. Iron meteorites tell us Prospects for 2004 13 George Alcock, samples of about core formation. Stoney- Review of observations 16 Libyan desert glass, cuttings from irons come from the boundary of old journals and information on core and mantle and are the most the Journal of the International beautiful meteorites, with Meteor Organisation. intermixed peridotite (olivine) and BAA COMET SECTION NEWSLETTER 2 THE COMET'S TALE

Comet Section contacts

Director: Jonathan Shanklin, 11 City Road, CAMBRIDGE. CB1 1DP, England. Phone: (+44) (0)1223 571250 (H) or (+44) (0)1223 221400 (W) Fax: (+44) (0)1223 221279 (W) or (+44) (0) 1223 571250 (H) E-Mail: [email protected] or [email protected] Antarctica: [email protected] WWW page : http://www.ast.cam.ac.uk/~jds/

Assistant Director (Observations): Guy Hurst, 16 Westminster Close, Kempshott Rise, BASINGSTOKE, Hampshire. (and also Editor of RG22 4PP, England. The Astronomer magazine) Phone & Fax: (+44) (0)1256 471074 E-Mail: [email protected] or [email protected]

CCD Advisor: Nick James, 11 Tavistock Road, CHELMSFORD, Essex. CM1 5JL, England. Phone: (+44) (0)1245 354366 E-mail: [email protected]

Photographic Advisor: Michael Hendrie, Overbury, 33 Lexden Road, West Bergholt, COLCHESTER, Essex, CO6 3BX, England Phone: (+44) (0)1206 240021

Subscription to the Section newsletter costs £5 for two years, extended to three years for members who contribute to the work of the Section in any way, for example by submitting observations or articles. Renewals should be sent to the Director and cheques made payable to the BAA. Those due to renew should receive a reminder with this mailing.

Section News from the Director

Dear Section member, IWCA III The last six months have been heavily packed with meetings. First there was the Meeting on The third International Workshop on Cometary Astronomy will be held at Asteroids and Comets in Europe Meudon and Paris Observatory, France from Friday 4th of June to Sunday in Mallorca quickly followed by 6th of June 2004. Its main objective is to promote cometary observations the pro-am discussion meeting at among amateur astronomers and optimise the benefit of these observations Milton Keynes at the beginning of for the use by professional astronomers. It will be an opportunity for May. Next came the BAA amateurs to meet professionals and exchange information about their Exhibition Meeting in June and at techniques. It will be organized by the ICQ and Société Astronomique de the close of the summer the France and sponsored by the Paris Observatory. observing workshop at the BAA Topics to be discussed during the meeting include Out of London meeting in York. • Cometary photometry (CCD, visual, light pollution effects, Reports on the first two are reference catalogs) and outgassing rates; elsewhere in this newsletter and • Comet imaging with filters and Spectroscopy; reports on the latter two will • Comet astrometry; appear in the Journal in due • Observation of trans-neptunians by amateurs; course. Next year there is another • Comet discovery and automatic sky surveys; MACE meeting, however the • Space missions to comets; main event is the International Workshop on Cometary Registration fee covering friday and saturday lunches, saturday reception, Astronomy that will be held in Paris. Details of this are given in bus transportation, coffee breaks and welcoming package is 70 Euros per the box opposite and I would participant. Deadline: 31 December 2003 (80 Euros after). encourage all members to attend. The preliminary deadline for Hotel room reservation fee for the 1st night is 52 Euros (Single) or 37 booking accommodation has Euros each (shared double). The deadline was 20 September 2003 and the already passed, however there is price is subject to change after this date. Full payment of the remainder still plenty of time to book. can be made at the time of the meeting.

It is perhaps just as well that there have been few comets to observe More details and registration forms are on the IWCA III web site. There as preparing for all the talks has is a link on the Comet Section web page. taken up a lot of time. However things are beginning to change. BAA COMET SECTION NEWSLETTER 2003 October 3

Comet 2002 T7 (LINEAR) is satellite link, so there is a chance and also from: Jose Aguiar, brightening nicely and 2P/Encke that for once I will be able to Alexandre Amorim, Alexander should also reach binocular maintain the web pages whilst I Baransky, Nicolas Biver, Jose visibility in the autumn. The am away. Carvajal, Stephen Getliffe, JJ Section has observations of the Gonzalez, Michael Jager, Andreas latter comet going back over 50 Conditions for comet observing in Kammerer, Heinz Kerner, Carlos years and I would like to the UK are generally declining Labordena, Martin Lehky, encourage visual observers to thanks to the widespread increase Rolando Ligustri, Michael continue the tradition as such long in light pollution. Maps on the Mattiazzo, Maciej Reszelski, Juan series can tell us much about the Campaign for Dark Skies web site San Juan, Pepe Manteca, Jose evolution of comets. Where show that there is now nowhere in Martinez, Stuart Rae, Tony possible try and use Cambridgeshire that has Scarmato, and Seiichi Yoshida instrumentation that matches that completely dark skies and such (apologies for any errors or of the past as this enhances their sites elsewhere in the country are omissions). Without these long term value. Next year rapidly declining. These maps are contributions it would be several comets may attain naked quite helpful in finding the best impossible to produce the eye brightness, however to see the local sites and driving a short comprehensive light curves that rare spectacle of two naked eye distance can make a significant appear in each issue of The comets at the same time you will difference to what you can see. Comet’s Tale. I would welcome have to head for the icy waters of Even in Antarctica light pollution observations from any groups the Southern Ocean in May. I is beginning to be a local which currently do not send will be visiting Antarctica yet problem, but it seems likely that observations to the BAA. again, however as last year I will regulation will be brought into the be there in February and March, Antarctic Treaty system, thus Comets under observation were: when they are still binocular combating light pollution on a 29P/Schwassmann-Wachmann, objects. Hopefully the weather whole continent. I hope that the 53P/Van Biesbroeck, 65P/Gunn, conditions will be somewhat more report from the UK Select 66P/du Toit, 116P/Wild, 2000 obliging than on my last visit, Committee due in early October SV74 (LINEAR), 2001 HT50 when the skies were unusually will bring the promise of some (LINEAR-NEAT), 2001 K5 cloudy. regulation in this country. (LINEAR), 2001 Q4 (NEAT), 2001 RX14 (LINEAR), 2002 O7 Whilst in Antarctica, I will be Since the last newsletter (LINEAR), 2002 T7 (LINEAR), installing a new weather observations or contributions have 2002 Y1 (Juels-Holvorcem). forecasting system at our Rothera been received from the following station, though I suspect that the BAA members: Peter Birtwhistle, Jonathan Shanklin forecasts will be no more accurate Werner Hasubick, Nick James, than they are here! Colleagues Gabriel Oksa, Jonathan Shanklin, will be installing a new permanent Tales from the Past

This section gives a few excerpts HM Sloop Waterwitch at place like New Zealand, where he from past RAS Monthly Notices Ascension Island, from the Cape was away from other observers. and BAA Journals. and from the Royal Mail Steamer It was very satisfactory to know Lady Jocelyn on passage from the that he had now the power of Cape to Mauritius. recording accurately the place of any comet he might come across. Mr Grigg discovered a comet last July [26P/Grigg-Skjellerup], but his observations at that time were not sufficiently accurate for them to be able to get a reliable orbit, but now if he were fortunate enough to discover another they hoped his observations would be The RMS Lady Joceyln such that the comet's orbit would HM Sloop Waterwitch be fixed with accuracy.’ The 150 Years Ago: Observations of a comet [1853 G1] seen from book reviews include one on 100 Years Ago: At a meeting Mr “Comets and their Tails” by F G HMS Centaur whilst at Buenos Crommelin said ‘a paper had been Ayres outer anchorage on 1853 Shaw. The author advances the received from Mr John Grigg theory that comets’ tails are April 30 and May 1 were reported recording observations of the in the June issue of Monthly merely optical appendages comet Perrine [1902 R1] and this produced by refraction of light Notices. The next month Lt would be published in the Journal. Goodenough sent further through the head, acting as a lens. Mr Grigg seemed to have re- The reviewer concludes ‘while observations and an apology for discovered for himself what was an error in the previous dissenting from many of his very well known to observers, conclusions, we may welcome measurements, saying that he had namely, the cross-bar micrometer. ‘worked out the degree of this evidence of increased zeal for Although this, as he said, was cometary astronomy in our distance from Castor as 58° well known, it was very creditable instead of 63°’. Other southern colonies’. The comet to Mr Grigg that he should have notes record the discovery of observations were reported from discovered it for himself in a BAA COMET SECTION NEWSLETTER 4 THE COMET'S TALE another comet [1903 H1] by ‘Our far flung colonies!] There was a energetic fellow member in New paper in the June issue on “How I 50 Years Ago:. The annual Zealand, Mr John Grigg’. It notes try to Realise a Comet’s Orbit” by report notes that five comets had that Nature (May 7) stated that the Edwin Holmes. In the annual been observed by members of the comet was discovered from Mr report, the Director [E W Section during the sessional year. Tebbutt’s observatory in Windsor, Maunder] notes that the Section George Alcock had begun NSW, when it was actually found now numbers 18 Members, with 3 systematic comet searching in from Thames, New Zealand. [It joining in the last year. He notes January and had so far logged a seems clear that one hundred the half dozen comets that had total of 34 hours in the five years ago the centre of the British been under observation during the months to May. Empire rather looked down on its year. Pro-am discussion meeting

Continued from page 1 storms have been observed over complex. Radar studies give us the last few years. Photography problems! They see very small Neil Bone, Director of the BAA can be very pleasing and also meteors and lots of them - perhaps Meteor Section introduced the scientifically useful. Trail fragments of asteroids rather than work of the Section. The BAA is photography and video work are comets. Recent TV results show the largest UK organisation very important. Spectra are being evidence for hyperbolic orbits collecting amateur observations. obtained by amateurs and could implying an interstellar origin if Denning was an early Director be analysed professionally. A few real. A third problem is that the and produced a catalogue of amateurs carry out radio work. density of meteors is generally meteor shower radiants. Another Results are published in the quite high compared to that Director, Prentice, was seconded Section newsletter and the BAA expected from comets, so there is to Jodrell Bank to correlate visual Journal. either evolution of meteoroids or and radio observations. Harold some of the theory is wrong! Ridley and George Alcock both Our next speaker was Iwan had long associations with the Williams of Queen Mary College, Andrew Elliot concluded the meteor section. Alcock in London, talking about meteor morning session with a talk on particular worked with Prentice streams, their formation, how to video meteors. It is very on plotting tracks. Prentice was a evolution and observation. For a easy if you have the right solicitor and many of his long time each aspect had been a equipment. It can give good observation reports have the wills separate discipline, for example scientific results, with modern of former clients on the reverse comet specialists weren't technology being a help. He had side! Today visual observers interested in the bits once they used an image intensifier system, concentrate on rate information. had left the comet. We have with the intensifier being the most A few observers using telescopes known since the 1860s that a lot expensive item. A wide angle (or binoculars) still do plotting of meteor showers are associated lens gives a 50° field and a similar and there are also photographic with comets. Small ejected limiting magnitude to the naked surveys. Fireball reports come in particles are blown away in the eye. The system needs an at the rate of around one a week, solar wind but large particles accurate time inserter and this can mostly seen at 11pm whilst out share the orbit with the comet. be manual, radio or GPS. Steve walking the dog! Occasional What happens next is highly Evans does most of the analysis of bright events are seen widely, but mathematical, but results in the the resulting videos, which form a the tracks often end over the sea. prediction of meteor storms etc. permanent record. Single station There may be possible fireball The sun vaporises ice in a comet work gives meteor rates, streams as there are some periods and the resulting gas ejection magnitude distributions, of enhanced activity, eg the end of speed is around 1 km/sec. clustering information and radiant June. Showers are listed in the Comets orbit the Sun at around 30 position. Two station work BAA Handbook, however this km/sec, so the particles must have allows triangulation, particularly year most showers are affected by a similar orbit to the comet as the when combined with moonlight. Neil has a portable difference in velocity is small, and photography. It is possible to add observatory (a sun lounger), and it is possible to show possible spectroscopy, but this hasn't yet showed his observing tools changes in the orbital parameters. been done in the UK. Lunar (several pencils and a red torch) It is actually a 3-D problem, so impacts have also been recorded. and the standard observing form. the plane of the orbit can change, A small number of cameras would A simple formula converts the and with it the position of the cover the entire UK for a fireball observed rate into a zenithal nodes. The nodal position of a survey. Photography gives 5" hourly rate and for example meteor is known very accurately accuracy down to about 0m, but Perseids observed at one a minute (it is the time when it is seen), so video gives accuracy of a few equates to a ZHR of 80. the shift in nodal position between minutes down to 5th or 6th Observations give a profile of the meteor and comet gives a measure magnitude. New software allows ZHR and the Perseids showed an of the out of plane ejection real time analysis of the data, unexpected spike of activity in the velocity. For the Leonids this whereas in the past it has often early 1990s, which was still amounts to around 20 m/s. taken three times longer than the present as late as 1997. Such Computer models can show the observations to reduce the data. surprises show the value of visual effect of differing ejection Once an orbit is known software observations. The profile of the velocities, but it is also a function by Nick James can be used to Geminids has changed over the of where the ejection takes place, visualise the orbit. Modern video last couple of decades. Leonid which makes the analysis more cameras at prime focus on a 25- BAA COMET SECTION NEWSLETTER 2003 October 5 cm telescope can reach 11m stars, pollution free areas (no, as this literally disappearing in front of but are not yet quite as good for would eliminate most our eyes and after 400 orbits meteor work. Andrew then observations from the UK), do (2,500 years) half will have gone. showed spectacular results from visual observers hallucinate If we are in a steady state Jupiter recent expeditions, including the (probably yes, as the brain often must be throwing in more objects 2001 Leonid storm over Arizona, lets us see what we expect) and to the inner solar system. the 2002 Leonid storm over should light curves only be Spain, and the 2003 Quadrantids. compiled from observations by Alan Fitzsimmons (Queen's experts (no, all observations are Belfast) told us about some of the valuable). interesting things that he is doing at the moment under the title of David Hughes (Sheffield Recent results in the ground based University) demonstrated how he imaging of distant comets. He used magnitude parameters concentrated on three aspects: derived from amateur visual why we should study nuclei, observations. Short period snapshot surveys and dedicated comets (those with period less observations. Spacecraft show than 20 years) are seriously that 1P/Halley is quite a large affected by Jupiter. Their median nucleus about 17 km long. period is 7.2 years, however when Sublimation is seen on the surface Some of the speakers perihelion is at 1 AU the period is giving jets of dust and gas. 5.46 years and when at 3 AU the 19P/Borrelly shows that the Jonathan Shanklin started period is 8.3 years. This means nucleus is complex and has real proceedings after lunch, giving a that the shorter period object goes geology, quite different from the brief history of the BAA Comet round more frequently and there theoretical construct of ground Section and lamenting the fact must be plenty of short period based observations. Nuclei were that early observations had comets with larger q (1.5 - 3 AU) formed in the outer solar system, disappeared during World War II. still waiting to be discovered. We which was a wild and dangerous Although George Alcock and can measure the size of a comet place at the time, and are Albert Jones had made visual either directly with the HST or via collisional ejecta from the Kuiper discoveries of comets, but a light curve as the log of the belt. They are a repository of amateur visual comet discovery radius is theoretically proportional organic matter and are important was probably now a thing of the to 0.2 H10. This absolute for studies on the origin of life. past, thanks to asteroid search magnitude can either be derived The nucleus is the source of the programmes such as LINEAR and by assuming that the comet coma and tail. Alan had run a spacecraft such as SOHO. brightens as 10 log r (=> H10) or survey programme to study bare However at the moment there was by fitting to the light curve (=> nuclei, which observed 56 objects still a 'twilight zone' where H). David said that it would be to get a size distribution. The amateurs stood a chance, helpful if light curves were William Herschel Telescope has a particularly in the Southern plotted as a function of log(r) new prime focus camera with Hemisphere. Visual observation rather than r or time. Different 2048x4100 pixels giving a of features in the coma and tail molecular emissions may have resolution of 0.25" per pixel. was also a thing of the past as different slopes. When he first 43P/Wolf-Harrington at 4.43 AU CCDs now gave much more plotted values from selected was magnitude 21.6 but still objective images. Amateurs periodic comets he didn't get a showed a slight dust coma. could however make significant very good fit, however revised 143P/Kowal-Mrkos at 4.74 AU contributions by visual magnitude values did better. There is still a was brighter at 20.5, but showed a studies. Observations of lot of scatter, which implies bare nucleus. Such objects are 153P/Ikeya-Zhang showed different surface activity. Around possibly bright enough for variation across the course of the 2 metres is lost from 1P/Halley amateurs to image, so they could apparition, possibly reflecting the each revolution, implying that it contribute to these studies. 1998 inhomogeneous comet nucleus will last for around 250,000 years. U4 (P/Spahr) was the most distant loosing several metres as it One might expect that size and object imaged at 6.14 AU (beyond rounded the Sun. Comet 2001 A2 perihelion distance are correlated, Jupiter) when it was 23.3. His (LINEAR) showed significant given that comets with shorter team is now moving on to variation with a period of around period will loose more material. dedicated observations, looking at a month, which might reflect A paper by Lamy shows no such size, colour and rotation. precession of the nucleus. Comet correlation, however David's 22P/Kopff was observed for a 46P/Wirtanen had a relatively interpretation of the data is that it total of 3.6 hours and showed a normal light curve, but by contrast doesn't disagree with the dust trail behind the comet. The 67P/Churyumov-Gerasimenko, hypothesis. The average Jupiter individual frames show a light the new Rosetta target, might be family comet starts with a radius curve with a period of about 6.15 similar to 1999 K5 (LINEAR), of around 3 km and slowly hours. 6P/d'Arrest has a period of which had a 'pathological' linear shrinks. The gradient of size 7.20 hours with an amplitude of light curve, peaking some 73 days versus perihelion distance will around 0.1. New planned studies after perihelion. During questions give a clue on the average age. include monitoring activity all David Hughes suggested that this There are no bright comets round the orbit and a search for might be due to a single active passing close to the Sun. The comet ice as no water has yet area becoming illuminated. average comet has a radius of 1.4 been detected on a nucleus. A Jonathan concluded by posing km and perihelion distance of 1.8 search for comets near the Sun is some questions: should AU. Short period comets are planned to come on line in a few observations be restricted to light BAA COMET SECTION NEWSLETTER 6 THE COMET'S TALE months with SuperWASP1 (Wide expensive digital SLRs are be continuously active. Angle Survey for Planets), a fully comparable to CCDs. Nick Observations of the light curve robotic telescope which will have emphasised the need to use the and inner coma may help to a 247 square degree field and standard naming convention when distinguish between m image down to 16 in 30 seconds. submitting images. Brian interpretations of Ai. Initial The primary task is to search for Marsden confirmed that orbital solutions for comet Ikeya- planets round other stars at the astrometry and imaging were Zhang showed that the orbits of opposition point, but they hope to important to check if objects on the comets of 1661 and 1532 were try and search for SOHO like the NEOCP where comets and similar, but the comet was soon comets at 45° - 60° elongation that it was very important to securely linked to that of 1661. from the Sun. submit results as quickly as The non-gravitational forces possible. When LINEAR reports appear to have been quite The session concluded with Nick an object they have no idea if it is different between the apparitions. James (BAA) describing CCD cometary or not. Further back in 1273 there are two imaging by amateurs. Automated possible comets, the best is one in searches such as LINEAR find Alan Fitzsimmons and Paul April which was seen for 21 days. practically everything, however Murdin briefed the gathering on 877 has an object in February and amateurs can carry out rapid possible grants for scientific March seen from Europe, though follow up, observe structure near projects. The RAS has a small Chinese records suggest May. the nucleus, do photometry and grants program open to fellows Linking 877, 1661 and 2002 gives monitor faint objects. CCDs also for peer reviewed proposals. a time for perihelion between give pretty picture. Is astrometry There is a six month cycle, with February 5 and 12 in 1273. If we worth doing? Yes, once you have £18,000 per year available assume the perihelion time for the images. Astrometrica distributed in grants ranging from 2002 and 1661 and change A1 (commercial software) is fast and £500 to £5000. They are (which is a function of A2) gives catalogues are good. It is normally awarded for purposes several possible results and a particularly important for objects not funded by PPARC, for return around 455, but implies a on the NEOCP. Peter Birtwhistle example travel, to teachers etc. close passage near Jupiter. Is is getting down to 19.8. Pro-am work would come within there a link to the comet of 1532? Photography didn't have enough this remit, but proposals must A 1 m/s split at one return would dynamic range to show structure come from fellows. Full details give a four year separation at the in the coma, but CCD processing are posted on the RAS web pages. next return, so one or other can be used to bring out details. The Faulkes and Liverpool fragment could easily make an For example Hale-Bopp had telescopes will be operational this encounter with Jupiter whose apparently stationary jets prior to summer and welcome proposals radius of influence is around 0.35 perihelion. A rotational gradient from amateurs, which can either AU. As a trial we can again filter enhances radial features be live or via email. The BAA assume the perihelion times in such as seen in 153P/Ikeya- has Ridley grants which are open 2002 and 1661, but set A1 = 0, Zhang. Photometry is difficult. to all astronomers. There is also then vary the perihelion time to What aperture should be used ? the Shoemaker grant in the US get a return in 1532. 2013 May 1 What comparison stars ? Are which has 35,000$ per year. is a possible solution for a split in filters needed ? [See my review of 77, though his preferred solution the MACE 2003 meeting - Ed] During the tea break speakers and is a perturbation in 451 that will Overall photometry is now seen audience were photographed, return in 200 years time, though as the most difficult area for which meant that we reassembled this requires a return in 956, amateurs. Specific targets for to hear Graeme Waddington which was possibly seen. amateurs include the potential speak on Random Meanderings Essentially the orbit is chaotic and Rosetta target 67P/Churyumov- by Jove slightly later than so prediction is very difficult. Gerasimenko, comets which have planned. Nothing much happened outbursts such as for 13.7 billion years, then along 29P/Schwassmann-Wachmann. came Kepler and Newton. For a Nick wasn't sure if spectroscopy few body problem we need to was valuable [again see the consider solar attraction, planetary MACE notes], however Maurice perturbations and relativity Gavin had obtained spectra of (ignore). Solar heating (radiation 2002 C1 and 2002 V1. Finally pressure, Poynting-Robertson the amateur could take pretty effect, Yarkovsky effect) on pictures and there is nothing comets gives outgassing. The wrong with this. In addition wide Marsden non gravitational forces field images do contain lots of are A = g(r), where A is the I 1 John, Guy, Brian, Kay and Nancy structure. New CCD chips such radial, A2 transverse and A3 the as Kodak KAF1600 at 14x9mm force normal to the plane. They and KAF1000 at 25x25 mm are only apply when the comet is Guy Hurst introduced John becoming comparable to film, but closer than about 3 AU of the Alcock, brother of George, and expensive. Alternatively it is Sun. The forces can change with Kay Williams George's possible to mosaic smaller fields time, for example in 7P/Pons- biographer, before asking Brian and these show considerable tail Winnecke. In the real world Marsden to present the George structure. Another technique is to outgassing is asymmetric on a Alcock Memorial Lecture. Brian use an ordinary camera lens with peanut shaped nucleus and peaks first met George on August 28 a CCD. Some digital cameras can after perihelion. It is also from 1959, the day following George's record comets and more discrete sources, which may not discovery of 1959f, though the IAU circular wasn't issued until BAA COMET SECTION NEWSLETTER 2003 October 7

September 1. This was the first but no nuclear condensation and Other SOHO comets also form a UK discovery since Denning had had perhaps passed through the group. If they are periodic we found 1894 F1 [though Candy Sun. A comet was seen in by du have no idea what the period is. accidentally found 1960 Y1 Ed] Toit (only) in 1945, then in 1970 From the short arcs observed by It was only observed for a week came comet White-Ortiz-Bolelli. SOHO it is impossible to tell the and was not seen after perihelion. In 1981 the Central Bureau orientation of the orbit, and the 1983d, which made the closest received reports from Solwind groups were only recognised after approach to the Earth of any about a possible comet from 1979, further objects were found. A few comet in the 20th century was which disappeared as it rounded comets pairs have been found in being observed exactly 20 years the Sun. Since then SOHO has ground observed comets, but no ago today. As well as making produced a multitude of objects. groups. Why does only SOHO sketches on drawing card, George Eight Kreutz comets have been see them? The group is also made copies on air letters. Brian observed from the ground, 6 from associated with the Arietids, had received a letter dated 1977 Solwind, 10 from the Solar 96P/Machholz and the November 29, where George Maximum Mission and 465 from Quadrantids. The low inclination referred to a thin pencil like beam SOHO making a total of 489 as of suggests that they might be short seen low in the sky on 1963 May 1. There is quite a spread in period objects. There are now 38 September 12, which may have the SOHO orbits, however they Meyer group objects, the Marsden been the comet discovered by are only approximate and in many group (similar to the Arietids) has Pereyra two days later. Ikeya- cases an orbit was only calculated 15 and the orbit passes close to Seki was a great sungrazing because we know that the Kreutz the Earth today. The Kracht comet as was the great September group exists. For well known group has a further 16 members. comet of 1882, when a fine orbits L=282 and B=35. Brian Another group is 2000 Q1, Y6 drawing was made from Putney. wasn't sure if the spread in SOHO and Y7. Excluding these groups The nucleus of this comet had elements was real or not. leaves 35 comets that pass within fragmented and is possibly related Sekanina allows splitting well 0.1 AU of the Sun of which 16 are to that of 1965, perhaps having away from perihelion and finds from SOHO. Several of these did split at a previous return early in pairs of comets coming in close not survive perihelion, including the 12th century - there was a together, which implies a all the SOHO objects. Those that comet in 1106 that may match. separation velocity of mm/s, survive did include 1680, 1962 Sekanina & Chodas (AJ, 2002) which doesn't match observed Seki-Lines and 2002 V1 (NEAT). suggest that the fragmentation separation velocities [and often occurred 18 days after perihelion the elements of pairs appear on 1106 February 13.5. Spectra different]. The problem is not of Ikeya-Seki showed many lines solved yet. The comet of 371 BC of iron. Other bright comets in is probably not connected with the 1843 and 1880 appear to be Kreutz comets, but it makes a related, with a period of a few good story! We don't know the hundred years, and to force a size of the progenitor. There relation would require the period should have been a bright comet to be 360 - 380 years, with a split in 1487, but no records have been in the late 15th century. The 1963 found so far. Eclipse comet seen in 1882 comet had a period of around 900 years and is perhaps another A question asked about the boring component of the 1106 breakup, names the majority of comets now although its orbit is clearly received and would names be different. The exact orbit depends dropped? The new designation very much on where Jupiter is in system introduced in 1995 is its orbit; there are lots of better than the old ones, but still possibilities, however Sekanina has problems. On asked about and Chodas suggest a link to the whether interplanetary boulders 1970 comet. In his original paper might cause comet splitting, Brian Brian had assumed a break-up at thought it unlikely as comets were perihelion, however this is not Kreutz group comet 1843 D1 in any case so fragile. necessarily the case. A comet seen on 1887 January 20 had a tail Jonathan Shanklin Professional Tales

The Populations of Comet- close encounters with planets This provides 20 dynamically Like Bodies in the Solar often result in near-constant distinct categories of outer Solar system J. Horner (Oxford), perihelion or aphelion distances, system objects in the Jovian and N.W. Evans (Cambridge), M.E. or in perihelion-aphelion trans-Jovian regions. The Bailey (Armagh), D.J. Asher interchanges, so the minor bodies Tisserand parameter with respect (Armagh), MNRAS can be labelled according to the to the planet controlling planets predominantly controlling perihelion is also often roughly A new classification scheme is introduced for comet-like bodies them at perihelion and aphelion. constant under orbital evolution. For example, a JN object has a So, each category can be further in the Solar system. It covers the perihelion under the control of sub-divided according to the traditional comets as well as the Centaurs and Edgeworth-Kuiper Jupiter and aphelion under the Tisserand parameter. The control of Neptune, and so on. dynamical evolution of comets, belt objects. At low inclinations, BAA COMET SECTION NEWSLETTER 8 THE COMET'S TALE however, is dominated not by the long-period -- according to way, the nomenclature for the planets nearest at perihelion or aphelion distance. The Tisserand Centaurs and Edgeworth-Kuiper aphelion, but by the more massive parameter categories now roughly belt objects is based on, and Jupiter. The comets are separated correspond to the well-known consistent with, that for comets. into four categories -- Encke-type, Jupiter-family comets, transition- short-period, intermediate and types and Halley-types. In this MACE 2003

The 2003 Meeting on Asteroids laptops to the host projector. This for 67P in 2009 and is planning a and Comets in Europe was held is a valuable lesson to learn if you campaign to observe it. His light on the holiday island of Mallorca. plan on giving talks yourself. curve suggests an outburst a few The weather wasn't quite as sunny days before perihelion and a rapid as shown in the holiday brochures Giovanni Valsecchi described change in slope at 1.85 AU on the and it soon became clear to me close encounters between NEAs way out, possibly related to H2O that the vast majority of tourists and the Earth. The mass sublimation switching off. A light get no further than the beach. distribution of these objects is curve by Seiichi Yoshida shows Inland at the north end of the approximately a power law. He the same outburst, and also one at island is a spectacular range of described the keyhole theory the previous apparition. [Note limestone mountains, with steep where a close encounter at one that some sources use poorly ravines leading down to the sea, return allows an even closer calibrated CCD photometry, yet on walks through them I rarely encounter at the following return. which frequently gives spurious saw another traveller. Although Each keyhole contains two effects Ed.] He suggested that the we were staying in a beach front collision possibilities. He coma became less condensed after hotel, 20 minutes walk down the estimates the error in calculations perihelion. He showed examples road was the internationally of future collisions done with the of CCD images of the comet, renowned nature reserve of analytical theory of keyholes to be which shows a prominent tail, Albufera, full of wildflowers and around 10%, mainly due to having even eight months after birds. The meeting was held at disregarded various gravitational perihelion. the Observatorio Astronomico de perturbations. Mallorca at Costitx near the centre of the island, which necessitated an exciting bus ride through narrow village streets several times each day. Here there is a very well equipped observatory, with a planetarium, and a wide range of telescopes, some under robotic control through the internet and others available for school teaching. The planetarium projector The dome of the robotic telescope Jure Skvarc described astrovirtel Mark Kidger updated us on the and the search for trojans of the 2002/03 apparition of outer planets. The highlight of 67P/Churymov-Gerasimenko, the this talk was the Italian probable new target for the spaceguard representative who Rosetta spacecraft. It is a became very upset when it relatively new entrant to the inner appeared that a possible NEO solar system with the perihelion hadn't been reported to them. distance around 4 AU prior to 1840 and only going below 2.75 Gerardo Avila reported on the Each dome houses an LX200! AU after 1959. The comet is spectra of comets. The Club of fairly active, so it is a potentially Amateurs in Optical Spectroscopy Here I generally describe only risky encounter. The changes in use a fibre optic linked those talks relating to comets, perihelion distance drive the spectrograph which has 1.5 Å however there was a good range activity by increased sublimation resolution. They have obtained of talks devoted to amateur blowing off crust. The Spanish spectra of Hyakutake, Hale-Bopp studies of asteroids. These are language group "Observadores and 1999 S4. They think that they summarised in a report in the Cometas" have been observing it. recorded evolution in the Na-D BAA Journal and are also 67P is much larger than lines in the spectra of Hyakutake available as abstracts on the 46P/Wirtanen at 2.5 km compared that appeared during the MACE web page at to 0.7 km radius. 67P/ apparently apparition and also those in Hale- http://www.oam.es/oam/mace/abs shows outbursts by about 1.5m a Bopp, which developed during tracts2.htm. Many speakers used few days before perihelion. 46P March and April. Although raw PowerPoint presentations, but shows a consistent light curve, spectra of 1999 S4 looked only a few followed the best though a 3m outburst reported in unpromising they do contain practice of using the pack and go September 2002 and shown in a useful information. The group is option and the local laptop. light curve from Seiichi Yoshida developing an Echelle Those that didn't often spent many was not seen in his CCD data. spectrograph which will have minutes interfacing their own Mark predicted another outburst better resolution (20,000λ/∆λ) on BAA COMET SECTION NEWSLETTER 2003 October 9 the 0.6-m telescope, which will first comet is. Waddington down to 21m, theoretically show spectra of a 6m star with a suggests that the second object is covering the northern sky in four 20 minute exposure. 153P as the track fits and gives or five days when used in survey the perihelion as March 27.5±1 mode. It will also be used for Andrea Boattini described NEO day. However the latest IAU discovery and follow-up work for search efforts. US programmes orbit suggests a perihelion in 1272 solar system objects, as well as are not complete, particularly in December. The Japanese record a other astronomical survey work the north, south and near the Sun. comet on 877 February 11 in which requires a quick response A Schmidt camera (roughly Pegasus and a comet was seen in time. equivalent to the IOA Schmidt in the west from Europe in March. Cambridge) was refurbished with Nakano links these with 153P, Jure Skvarc described the a CCD camera. It can point to however the European comet was Fitsblink software developed at within 8° of the horizon. The best in Libra, whereas the Nakano Crni Vrh, which has image strategy was to observe at 50°-55° orbit puts it in Cygnus. It would processing and objection elongation down to 20m. not have been seen from Europe detection facilities. It can't detect at sunset unless it was very bright. trails yet. It uses the USNO SA, Marcos Voelzke reviewed comets The orbit of 1532 R1 is similar to Tycho 2 and will use USNO B and their origin and evolution. that of 1661. If the 1661 comet catalogues for astrometry. It uses What are comets? - the word had a similar light curve to the Tycho 2 and LONEOS (by Skiff) comes from cometes or long present apparition it would have for photometry and will use the haired star. They are a mix of been better placed for observation Landolt catalogue in future. dust and ice - we know about the before perihelion, and brighter, There is an option for comet nucleus of 1P/Halley from Giotto. but there are no reports either in photometry, with automatic star We study comets to understand late December or in mid January. exclusion, background subtraction solar system evolution and the Possible explanations are an and tail exclusion. It will produce possible cataclysmic effects they outburst at perihelion or an a report directly in ICQ format may have on the Earth etc. asymmetric light curve, but and is designed to help beginners. Spectra show their composition. neither is credible. A possible It is possible to show explanation of the 1273 reports is morphological evolution by an incorrectly transcribed date. subtracting image pairs taken a There is a problem linking the few hours apart, and this was expected magnitude to the illustrated by images of suggested orbital fits. The 1P/Halley. We can explain observational evidence tends to disconnection events in the tail by favour the Waddington linkage in the nucleus passing through a 1273. The Chinese reports magnetic field change, which suggest that the comet was blue accounts for about 70% of cases. and therefore it must have been Another theory suggests that the bright to see colour, however the solar wind pressure varies, but light curve gives a magnitude of Herbert Raab & Bill Yeung this only explains 22% of cases. 1.5 and fading even if the 1661 He wants to extend the theories to light curve is used. Alternatively Herbert Raab, producer of the other comets and to use 3-D the comet may show strong widely used Astrometrica imaging. secular fading. This could be software, described some new star explained if the 1532 and 1661 catalogues. GSC 2.2, USNO B Mark Kidger gave another talk, objects are two fragments of a 1.0 and UCAC (USNO CCD this time on 153P/Ikeya-Zhang. comet that split in the first Astrograph Catalog) V2 and The previous longest return period century, with the 1532 body being compared them with the USNO A was 35P/Herschel-Rigollet, which the principle component. A 2.0. USNO A is based on the was seen in 1788 and 1939. 153P smaller fragment might be POSS at 0.25" accuracy for 1957 with no proper motions. USNO B was the first comet with a expected to show secular fading. 9 confirmed period longer than 200 The orbit of 153P permits close has 10 stars, relative proper years as the proposed link to 1661 encounters with Jupiter at the motions (relative to the mean sky, is secure. Previous returns, in 877 descending node. A split in 58 rather than the fixed background of quasars) and is complete to and 1273, are less secure [See the AD, followed by a close m talk by Graeme Waddington at the encounter with Jupiter in 485 21 . Positions are accurate to 0.2" at the current epoch. GSC Proam meeting]. It was should separate the components. 6 discovered on 1661 February 3 in This implies that the bright 2.2 is 455 x 10 stars and has a the morning sky, with a 6° tail. component will return at the end limiting magnitude of 18.5 (R) Shortly after discovery Hevelius of this century. and 19.5 (B), there is no proper reported it fainter than Altair. It motion and the accuracy is 0.2" in was last seen on March 28, Maria Teresa (Maite) Merino 1993. Version 2.3 is due in 2003 presumably with the naked eye. described the transformation of an and this will include proper A rapid decrease in the degree of old Baker-Nunn Camera from a motions. UCAC 2 is based on condensation was reported. In military base at San Fernando in recent CCD observations. At 50 x 106 stars in size it includes proper 1273 a comet was seen on southern Spain. It will feature a m m February 5 in the evening and 17 new large format CCD camera motion, stars from 8 to 16 at - in the morning. One was also and will be used in a robotic 90° to +45° declination to an seen two months later as a blue- mode. It will be installed at Tossa accuracy of better than 0.1". The white guest star in Auriga, d'Alp in the Catalan Pyrenees by new catalogues are significantly however this can't be 153P if the the end of 2004 and might get better than USNO A. The UCAC is available on 3 CDs from USNO BAA COMET SECTION NEWSLETTER 10 THE COMET'S TALE at ad.usno.navy.mil/ucac. USNO profile on the sunward side. moment). The catalogue is from B is available on line as is GSC Comet observations therefore 1950 POSS plates (or more 2.2. The UCAC is good for make a good probe of the solar recent) and is not a photometric photometry (approximating to a wind. At high ecliptic latitude the catalogue. The B mags are too yellow-red filter [579 - 642 nm]) wind is fast and steady, whilst at bright above 13m so that 20m ≡ to around 0.3m. low latitude it is highly variable at 19.2 but is generally close to the solar minimum but more variable truth at 14m. R is within 0.2m Herman Mikuz, well known for all round at solar maximum. from 11 - 19 (18 USNO ≡ 17.8) his CCD work, described the new Chandra and XMM-Newton have and the standard deviation is 0.6-m robotic telescope at Crni both observed comets. XMM about 0.25m. 60% of stars are Vrh observatory, which will reach observed 1999 T1 (McNaught- within this and each field may 20m with a 5 minute exposure. Hartley) and 2000 WM1 have 100 stars, so outliers can be They discovered an NEO 2003 (LINEAR). 2000 WM1 didn't rejected (Astrometrica does this EM1 whilst imaging comet 2001 have any emission above 1 keV, automatically). You should RX14 and confirmed 2003 H1, but they recorded 106 X-ray NEVER use single star which was essentially stellar, but photons. The profile is a function calibrations. The error generally the image profile was slightly of 1/r. XMM can also measure reduces as the square root of the broader than that of a star. 2003 spectra, thus identifying electron number of stars used. The biggest H2 was fainter, but clearly transitions. Chandra observed single issue is actually sky diffuse. You need to be very 2002 C1 on two nights, finding subtraction. As an example using systematic in calibrating and completely different X-ray 2002 T7 the light curve scatter has focussing the telescope in order to morphology. CCD images or ±0.2 mag. It is possible to get good results. photographs taken on 2002 April improve things by using a range 15 between 01:54 and 05:09 of fixed apertures, 10", 20" etc. Korado Korlevic commented that would help understand the They have developed a custom comet 1998 VS24 (LINEAR) was reasons. The X-ray coma would program (FASE3) to permit multi- discovered as a one night stand at perhaps be comparable to the aperture photometry and Visnjan, but as they couldn't Lyman alpha cloud in size if astrometry, and also give good follow it up they lost the credit for sufficient sensitivity could be sky subtraction. it. used. Gyula Szabo introduced the idea Konrad Dennerl spoke about the Richard Miles showed that the of an Afrho database. It is recent discovery of X-rays from Sony CCD HAD chip is actually difficult to do photometry on a comets. ROSAT observed comet quite a close match to Hipparcos diffuse comet coma. The 1996 B2 and detected X-rays, and so can be used without a filter observed length of tail or coma which was a big surprise. The if a simple transform is used. size depends on equipment and team obtained 9 images which This assumes that the stars used sky conditions. The coma show a factor of four variation in have a similar B-V to the asteroid. brightness depends on aperture, brightness over a few hours. The the brightness of the nucleus peak of X-ray flux is offset in the In his third talk Mark Kidger depends on seeing, equipment, solar direction. The X-ray coma looked at amateur CCD coma etc. Sunlight is scattered is much larger than the optical photometry. The advent of the from dust in the coma towards the one, and elongated perpendicular CCD has been the biggest Earth, therefore the ratio of comet to the solar direction. They then revolution in cometary flux to solar flux is a measure of looked at the archive data from observation in the last 50 years. It the dust in the coma. Dust is the satellite and found several provides both astrometry and characterised by a function of the comets showing X-ray emission, photometry, however the albedo and dust density (Afrho). including one prediscovery image, photometry is generally unreliable He would like to create an archive down to a visual magnitude with a scatter of perhaps 4m. of Afrho measurements supported around 12. All comets inside 2 There is a need to standardise in a by a helpful web page at AU and brighter than 12m were way that is simple, quick and cara.uai.it. AstroArt software seen. The X-rays are generally adequate for the purpose. We includes tools for generating the low energy. The X-rays don't must accept unfiltered information needed. As an follow the optical morphology photometry, and the fact that example photographic data for and in particular don't follow the comets are not point sources, 67P from Kitt Peak in the 1980s dust. There is a correlation which makes life harder. The gives very similar results to recent between the X-ray and optical MPC list an N (≡m2) or T (≡m1) Italian observations using CCD. -4 flux, but the X-rays are some 10 magnitude, however the m2 He would welcome more the intensity. Gassy comets are reports tend not to be a bare observations. Mark Kidger brighter in X-rays. Protons, nuclear magnitude. The Spanish suggested that the archive should electrons and helium nuclei form method is to assume that do the calculation of Afrho from 99.9% of the solar wind, but the unfiltered magnitudes the input data. 0.1% of 'heavy' ions (eg C6+, O6+) approximate to R, for everyone to are responsible for the X-rays by make the reductions with one Mike Kretlow concluded the exchanging electrons from neutral package (eg Astrometrica), to use papers with a talk on the splitting H2O in the coma giving emission a standard aperture of 10" for of comets. In the past 160 years at discrete X-ray energies, in nuclear magnitudes and to we have seen about 35 split particular at 568eV. Therefore calibrate using USNO A2.0 R comets. There are two split comet the X-ray emission is more from magnitudes (this is widely families - the Kreutz group and the solar wind and this explains available, has many stars and the Marsden/Mayer/Kracht group. the crescent shaped emission there is nothing better at the D/1993 F2 split as a result of tidal BAA COMET SECTION NEWSLETTER 2003 October 11 forces. High resolution imagery 2%/century/object so that over the break-up events closer in time to shows that fragments are sub lifetime of a comet (107 years) the actual event. kilometre in size. There are two about 1000 events may happen to types of fragmentation: A: two or a comet. If each fragment was Several poster papers were on three fragments leaving a primary 50-m in radius this sums to a display in the foyer of the body, a process which may recur parent 0.5 - 1 km in radius so it is planetarium, which also housed and the fragments can survive for an important mass loss factor. an exhibition of meteorites. Mark years. B: many fragments, with Splitting may be due to tidal Kidger had a poster on ‘Revealing no primary (eg D/1993 F2, 1999 forces, rotational forces, thermal the nucleus of long-period comets S4) with the parent completely stress, internal gas pressure or with Canaricam’. This is a mid- destroyed. Backward integration impact. The first known example infrared imager planned to be generally doesn't give a is 3D/Biela, which split into 2 in installed on the Gran Telescopio satisfactory break-up point, which 1845/6. It was seen again in Canarias, a 10 metre telescope makes it tricky to link up 1852/3 and has been lost since which is due to start operation in fragments. Sekanina has then. 73P/Schwassmann- 2005. By combining the infrared published lots of papers on more Wachmann split in 1995, with an and visible photometry it will be than 30 comets over the last 25 outburst occurring just before the possible to determine the albedo years. This uses a simple 2-body split and perihelion. 57P/du Toit- and diameter of distant comets. model, which is not suitable for Neujman-Delporte split in many type B and even the 2-body model fragments in July 2002, although The next MACE is planned for gives multiple solutions. The there was still one primary. Coma Frasso Sabino near Rome in 2004. model implies that splits can arc-lets or ring-lets as seen in occur anywhere along the orbit image processed views of 2001 Jonathan Shanklin, with thanks to and the lifetime of fragments can A2 may indicate breakup or may the speakers for corrections to my be very variable, being weeks to relate to outgassing. Amateurs original notes years. The separation velocity is need to monitor comets, both as a 0.1 to 15 m/s, but generally 0.3 - 4 light curve and high resolution m/s. The splitting rate is around CCD images in order to detect

Springer Competition Winners

Thanks to the generosity of Springer-Verlag the comet Section was able to run a competition in the spring, with prizes being copies of the new book on Observing Comets by Nick James and Gerald North. The winning entries appear in this edition of The Comet’s Tale and the runners up will appear next time. A review of the book, by Guy Hurst, appeared in the August Journal and one by John Bortle appeared in the September issue of Sky and Telescope. The book is a valuable addition to the observers’ library and I can strongly recommend it.

Margaret Cullen submitted her drawing “Cat watching Hale-Bopp” to win the SPA Members division, Gabriel Oksa’s essay won the BAA division and Bill Ward’s essay won the open division. Congratulations to all these on their success. Why I Observe Comets Gabriel Oksa

I began with a systematic weeks were totally clouded off plasma and yellowish dust was observing of comets in 1996 with no sign of Sun, stars and easily visible. during my stay at the comet. But exactly around the Loughborough University, time of the comet's closest Since that time, seven years of the Loughborough, England, where I approach to the Earth, the weather regular observing of comets have received the Royal Society changed and I vividly recall that gone and my interest did not Fellowship in the field of parallel evening in late March with the vanish. I observed, among many computing. At that time, the comet nearly overhead, having others, the famous comet Internet was new to me and by large coma and long tail - a 55P/Tempel-Tuttle rushing across means of it I established first stunning sight even from the the sky in January 1998, contacts to the British middle of the city! interesting changes in the tail and Astronomical Association, coma of the comet C/1999 S4 in especially to its Comet Section. And then, of course, the Great spring and summer 2000 (the From April 1996 onwards I am Comet Hale-Bopp! My comet disintegrated in July 2000), the only Slovak member of the observations were split between the outburst of comet 41P/Tuttle- BAA. England and Slovakia. The Giacobini-Kresak in December climax came in those cold 2000 and a beautiful visual The year 1996 will be recalled as evenings of April 1997, when I emission spectrum of the the year of Great Comet was able to record distinctly bluish pseudo-nucleus Hyakutake. I remember those photographically the changing of comet 153P/Ikeya-Zhang in foggy days in Loughborough forms of its wavy plasma tail and March 2002. Having used when its finding was announced to observe the brightening and several observational techniques and the special BAA circular was lengthening of its dust tail and the including the CCD camera, I am issued with a map of comet's famous dust envelopes around its fascinated by wonderful cometary visibility. And then I remember pseudo-nucleus. Using even drawings of late Mr Alcock, so the increasing frustration due to small binoculars, an amazing nowadays I am trying to the 'English' weather when several colour contrast between the blue BAA COMET SECTION NEWSLETTER 12 THE COMET'S TALE reproduce some of my observations in this way.

To observe a comet, you must not be lazy. Sometimes you have to abandon your warm bed early in the morning - often too early for 'ordinary' people. Sometimes you have to change your evening plans suddenly when a beautiful transparent sky of a special blue colour appears following the passage of cold front. You have to know the sky well enough to find a comet. You have to remember that things completely change during an evening or morning twilight so that, in such circumstances, to find even a bright comet close to the horizon may be a challenge. You need a lot of patience in those cloudy nights when only a few holes of clear sky bring you some hope, and you firmly believe that one of them will reach a comet and stay there for a sufficiently long time to make an observation. You need all of these skills - and still, a successful observation is not guaranteed! Every time I go out Cat watching Hale-Bopp - Margaret Cullen to observe comets I am not sure what, if anything, I shall see. This uncertainty is a substantial part of some sort of relationship arises measurements in near future. my life with comets. between an observer and a comet, Unprecedented details will be especially if a comet is observable added to the enigmatic nuclear So, why do I observe comets? It for a longer time period. And it is images of comets 1P/Halley and is a joy - every time a comet is in a communication and sharing with 19P/Borrelly. But, regardless to my eyepiece I feel lucky. It is a a community of equally-minded the advances of science, the thrilling experience - just think of people in the world. comets will remain delightful the depths of space and time, objects for amateur astronomers which a comet is coming from! It Exciting days should be ahead for due to their intrinsic beauty, is a perception of beauty and very all cometary enthusiasts. Several unpredictable behaviour and special order in the cosmos. It is a space probes are planned to visit connection with the origin of our curiosity - how will a comet some comets and analyse their Solar system. appear today? I would say that composition by 'in situ' The Importance of Amateur Comet Observations Bill Ward

Every comet is different with it’s and 19th centuries with their will appear or an unusual event own story to tell and each one famous comet hunters. Nowadays will occur. The process by which presents a new piece of there are relatively few telescope time is granted is highly information about the solar professional cometary competitive with large telescopes system. Comets by their very programmes with most solar being over subscribed. This nature are varied and system observing programmes process tends to favour projects unpredictable. It is because of this dealing with other small bodies with a definite short-term goal that amateur astronomers can and such as near earth asteroids and and that will yield a scientific do play an important part in more recently trans Neptunian paper suitable for publication. cometary astronomy simply by objects. Comet observations require a the virtue of being "amateur". In longer time scale. Major this context amateur has nothing A great deal of time is required to observatories simply cannot to do with the standard of conduct searches and carry out justify the expense of using major workmanship only in the meaning observations. From the discovery instruments for such work of being un-waged and in of a comet to its orbit back into because of the restrictions placed conducting observations for the the far reaches of the solar system upon them. enjoyment to be found in it. may be months or years. As comets are unpredictable there is Considering this situation begins Amateur cometary astronomy is no way of scheduling observing to reveal the importance of sometimes viewed as slightly time in advance as it is impossible amateur comet observations. The quaint and reminiscent of the 18th to say when an interesting comet key issue is one of flexibility, of BAA COMET SECTION NEWSLETTER 2003 October 13 being in the position to observe Comet Hyakutake in 1996 and comet observations constitute a whatever and whenever without Comet Hale-Bopp in 1997 major scientific archive. any other concerns or restrictions. coupled to the imminent A flexibility which professional appearance of two more possibly Amateurs also have the advantage observatories cannot match. bright comets (Comet 2002 T7 of numbers and coverage. With and Comet 2001 Q4) a whole new many eyes watching the skies Another important element that is generation of people have been there is the chance that any given now fundamental to amateur (or shortly will be) exposed to event will be caught somewhere. comet observations is one of comets and astronomy.) Even casual observations are technology. The developments in important too if a bit of care is detectors, that is the now Even with nothing more than ones taken. As astronomers we are ubiquitous CCD camera, allow eyes, there is a huge array of plagued by the weather and you the amateur to work at binoculars ranging from just might happen to be in the magnitudes that were impossible lightweight models to huge right place at the right time to get only a few years ago! Combined 150mm monsters which allow that critical observation, it could with the availability of powerful many comets to be followed be cloudy elsewhere! desktop computers, this allows visually. It should be noted that real quantitative data to be hand written visual observations The importance of amateur comet produced to a high standard. are just as valuable as the “hi observations cannot be Software is readily available and tech” CCD ones. One only has to underestimated as it is through the photometry and astrometry are consider historical observations to inherent flexibility, readily now relatively simple tasks. see this. Many comets would not available technology and Images of remarkable detail are have been found had it not been coverage that amateurs have now common place through the for those 18th and 19th century which allows useful observations use of both modern film and CCD amateurs exploring the heavens to be made in conjunction with cameras. (A by-product of these and our understanding of comets professional research ultimately spectacular images is to raise would be poorer if it were not for allowing us to know more about public awareness about astronomy these same people leaving us their these fascinating objects. in general. With the appearance of notes. Properly recorded amateur Comet Prospects for 2004

2004 sees the return of 18 Circulars, Comet Section close approach to Jupiter in 1936 periodic comets. None are Newsletters and on the Section, which reduced its perihelion particularly bright and the best are CBAT and Seiichi Yoshida's web distance from 2.4 to 1.6 AU. It likely to be 78P/Gehrels and pages. Complete ephemerides made an exceptionally close 88P/Howell. Three long period and magnitude parameters for all (0.003 AU) approach to Jupiter in comets are likely to put on good comets predicted to be brighter 1841, which switched its previous shows. 2001 Q4 (NEAT) reaches than about 18m are given in the perihelion distance into the new perihelion in May, when it could International Comet Quarterly aphelion distance. It was reach at least 3rd magnitude. Handbook; details of subscription discovered in 1924, then lost until Northern Hemisphere observers to the ICQ are available from the 1951. Its next apparition, in 2010, will first pick it up just after comet section Director. The will be unfavourable. perihelion as it rapidly moves updated section booklet on comet north. 2002 T7 (LINEAR) could observing is available from the 48P/Johnson was discovered by also reach 3rd magnitude at closest BAA office or the Director. Ernest Johnson at the Union approach in May, however Observatory in South Africa in Northern Hemisphere observers 29P/Schwassmann-Wachmann 1949, following a very close will have lost it as a binocular is an annual comet that has approach to Jupiter in 1931. It is object in mid March. Observers frequent outbursts and seems to now in a stable orbit between at far southern latitudes may be be more often active than not at Mars and Jupiter and no close able to see these two naked eye the moment, though it rarely gets approaches are predicted for some comets at the same time. 2003 K4 brighter than 12m. It begins the centuries. At favourable (LINEAR) could reach 6th year in Aquarius, but spends most apparitions, such as its first two magnitude as it brightens on its of the year in Pisces, reaching returns, it reaches 13th magnitude. way to perihelion. Several other opposition at the end of The next three returns were long-period comets discovered in September. The comet is an ideal unfavourable, with the comet previous years are still visible. target for those equipped with reported to reach only 18th CCDs and it should be observed magnitude. Returns are now Theories on the structure of at every opportunity. UK based improving, and at the last return, comets suggest that any comet observers should be able to follow Werner Hasubick reported could fragment at any time, so it it throughout the second half of observing it at 13.5. It could is worth keeping an eye on some the year. reach a similar magnitude at this of the fainter periodic comets, apparition, though it will be best which are often ignored. This 43P/Wolf-Harrington is at its seen from the Southern would make a useful project for brightest (12th mag) at the Hemisphere. CCD observers. As an example beginning of the year, and slowly 51P/Harrington was observed to fades as its elongation in the 62P/Tsuchinshan The comet fragment in 2001. Ephemerides evening sky decreases. This is the was discovered at Purple for new and currently observable comet's tenth observed return. It Mountain Observatory, Nanking, comets are published in the is in a chaotic orbit, and made a China in 1965, following a close BAA COMET SECTION NEWSLETTER 14 THE COMET'S TALE approach to Jupiter in 1960, slowly decreasing and is currently which reduced the perihelion around the lowest for 200 years. Two long period comets are likely distance from 2 to 1.5 AU. The eccentricity is slowly to become naked eye objects. Unusually, the comet's name increasing, with a marked jump in C/2001 Q4 (NEAT) was derives from that of the both following a moderately close discovered at Palomar on 2001 observatory rather than those of approach to Jupiter in 1995. This August 24.40 when it was nearly the discoverers. At a good return is extremely favourable, three years from perihelion and apparition such as in 1985 it can with the comet reaching over 10 AU from the Sun. It reach 11m and as the perihelion opposition and perihelion within a begins the year as a Southern distance will continue to decrease fortnight of each other. At the last Hemisphere binocular or easy future returns may be even better. return the comet reached 12th telescopic object and remains at At the last return the comet was magnitude and it should do at high Southern declination until it recorded at around 13th magnitude least a magnitude better this time nears perihelion in May. By then and this time it could do a round. It should become within it will have brightened magnitude or more better. It visual range of favourably placed considerably, and could be an should be picked up as a 13th observers by late spring, but UK easy naked eye object. Adopting magnitude object in the observers will probably need to a conservative magnitude September morning sky, wait until July when it should be a equation predicts a peak of 3rd brightening throughout the rest of 12th magnitude object in the magnitude as it emerges into the the year. It tracks from Gemini in morning sky. It continues to northern evening twilight in the September through into Leo at the brighten on its way to opposition second week of May, though it end of the year, when it could be and by October should be at 10th could be 1st magnitude. Tail 11th magnitude. magnitude. It spends most of the development is likely to be good, apparition in Aries, where it particularly in the first half of 69P/Taylor A series of Jupiter completes its retrograde loop in May, with a maximum length of encounters in the 19th century mid December, by which time it 10° - 25°. Observing reduced the perihelion distance is fading towards 11th magnitude. opportunities are best in the from 3.1 to 1.6 AU and led to its second week of May as the moon discovery by Clement Taylor, 88P/Howell Ellen Howell leaves the sky. It remains an with a 0.25-m reflector from discovered the comet in 1981 with evening object, becoming Herschel View, Cape Town South the 0.46-m Palomar Schmidt. It circumpolar in June, when it may Africa, in November 1915. It was passed 0.6 AU from Jupiter in still be just visible to the naked quite bright, 9th magnitude at 1978, which reduced the eye. It passes from binocular best, and shortly after perihelion, perihelion distance, but the range by the end of July, but will in 1916 February, E E Barnard biggest change to its orbit remain visible to telescopic found a double nucleus, each with occurred in 1585 when an observers to the end of the year. a short tail. The secondary encounter reduced q from 4.7 to nucleus became brighter than the 2.4 AU. The standard light curve C/2002 T7 (LINEAR) reaches primary, but then rapidly faded was not a good fit to the perihelion a few weeks before and the primary also faded more observations at the last return and 2001 Q4, but will be at its best at rapidly than expected. The comet a better fit was obtained using a around the same time, though was then lost until 1977, when linear light curve that peaked 28 only for Southern Hemisphere new orbital computations led to days after perihelion, thus observers. It too begins the year the recovery of the 'B' component confirming the view that the as a binocular object, but at this by Charles Kowal with the comet is brighter after perihelion. time it is best placed for Northern Palomar Schmidt. The 'A' The comet was never well placed Hemisphere observers. It remains component was not found. The for viewing in the UK at the last a binocular object, dropping into comet has had several encounters return and will not be at this the evening twilight in the first with Jupiter, the closest recent one return either. Elsewhere it should week of March. It emerges from being in 1925, and had very close be picked up at 12th magnitude in solar conjunction as a naked eye (0.06 AU) encounters in 1807 and January as it emerges from solar object in mid April and continues 1854. The comet was not conjunction. The comet should be brightening, even after perihelion, expected to be brighter than 15th at its best in mid March when it as the distance from earth magnitude at its last return, could be 10th magnitude. decreases on the way to a however it was discovered at moderately close approach at 0.27 around 12.5 in mid January 1998. 95P/Chiron is an unusual comet AU in mid May. Equatorial The observations suggest that it in that it is also asteroid 2060. It observers get the best view as it suffered two outbursts. This will reach around 17m when at emerges from conjunction, but at makes it difficult to predict the opposition in July in Sagittarius. closest approach it is a Southern likely brightness at this return, but CCD V magnitudes of Chiron Hemisphere object of 3rd or if it maintains the level of activity would be of particular interest as perhaps 1st magnitude. The tail at it might reach 11th magnitude at observations show that its this time could extend as much as the end of the year. It will absolute magnitude varies 40°. Thereafter the comet fades, become visible in the late summer erratically; it is currently around passing from binocular view in morning sky at perhaps 13th 6. It began an outburst in 2000/01 July and re-enters solar magnitude and CCD observers though it is likely to be fading conjunction in August. It might should treat it as a priority object. again in 2004. It was at be picked up again as a 13th perihelion in 1996 when it was magnitude object at the end of 78P/Gehrels Tom Gehrels 8.5 AU from the Sun and will be October. discovered this comet at Palomar nearly 19 AU from the Sun at in 1973. Its perihelion distance is aphelion in around 40 year's time. BAA COMET SECTION NEWSLETTER 2003 October 15

C/2003 K4 (LINEAR) reappears Hemisphere and may reach 11th in 2004 February after solar magnitude in March. Looking ahead to 2005, no bright conjunction and reaches binocular comets are predicted to return. range in May. We will loose it Several other comets are at The best object for UK observers into conjunction again at 6m in perihelion during 2004, however is likely to be 9P/Tempel, which 2004 September and it will pass they are unlikely to become will be a faint object in large through the SOHO LASCO fields brighter than 13th magnitude or binoculars from May to June. as a 5m object in 2004 October. are poorly placed. 40P/Vaisala, Several other periodic comets Southern Hemisphere observers 42P/Neujmin and have favourable returns, but they will pick it up at the end of the 121P/Shoemaker-Holt are 13th will all be telescopic objects. month and it should remain a magnitude or fainter but within References and sources naked eye object until 2005 range of larger amateur January. telescopes. 58P/Jackson- Nakano, S. and Green D. W. E., Neujmin, 103P/Hartley, Eds, International Comet A few other long period comets 104P/Kowal and D/Haneda- Quarterly 2003 Comet Handbook, will still be visible at the Campos have unfavourable (2002). beginning of 2004. 2001 HT50 returns. 111P/Helin-Roman- Shanklin, J. D., Observing Guide (LINEAR-NEAT) will be fading Crockett, 120P/Mueller, to Comets, 2nd edition (2002) from 12th magnitude at the start of 130P/McNaught-Hughes, Marsden, B. G. Catalogue of the year, but it is well placed in 131P/Mueller, 1996 R2 Cometary Orbits, 15th edition, the evening sky in Pisces. It will (Lagerkvist), 2002 L9 (NEAT), IAU CBAT, (2003). be lost in the evening twilight by 2003 E1 (NEAT), 2003 L2 Kronk, G. W., Cometographia, the end of February. 2002 O7 (LINEAR), 2003 O1 (LINEAR) Cambridge University Press, (LINEAR) is fading from 11th and 2003 S1 (P/NEAT) are (1999) and magnitude in Aquarius, but sinks intrinsically faint or distant http://www.cometography.com. into the twilight even more comets and will not come within Belyaev, N. A., Kresak, L., quickly and will be gone by the visual range. Ephemerides for Pittich, E. M. and Pushkarev, A. beginning of February. 2003 H1 these can be found on the CBAT N., Catalogue of short Period (LINEAR) is best placed for WWW pages. D/Haneda-Campos Comets, Bratislava (1986). observation from the Southern has not been seen since its discovery in 1978. Jonathan Shanklin Comets reaching perihelion in 2004

Comet T q P N H1 K1 Peak 58P/Jackson-Neujmin Jan 10.0 1.39 8.27 5 11.0 15.0 15 D/Haneda-Campos Jan 10.2 1.27 6.41 1 13.5 10.0 16 2003 L2 (LINEAR) Jan 19.3 2.86 10.0 10.0 17 40P/Vaisala Jan 22.9 1.80 10.83 6 8.9 15.0 13 2003 E1 (NEAT) Feb 13.5 3.25 50.9 12.5 5.0 17 2003 H1 (LINEAR) Feb 22.6 2.24 6.5 10.0 11 2003 O1 (LINEAR) Mar 17.2 6.85 6.0 10.0 18 43P/Wolf-Harrington Mar 17.9 1.58 6.45 9 9.9 5.8 12 2003 S1 (P/NEAT) Mar 26.0 2.60 9.69 0 11.5 10.0 18 2002 L9 (NEAT) Apr 6.2 7.03 8.5 5.0 17 88P/Howell Apr 12.6 1.37 5.50 5 4.7 24.9 9 2002 T7 (LINEAR) Apr 23.6 0.62 6.0 7.5 3 104P/Kowal May 9.7 1.40 6.18 3 9.8 9.3 13 2001 Q4 (NEAT) May 15.9 0.96 6.5 7.5 3 103P/Hartley May 18.0 1.04 6.40 3 8.1 15.0 10 1996 R2 (P/Lagerkvist) Jun 7.4 2.62 7.39 1 11.0 10.0 17 29P/Schwassmann-Wachmann Jul 10.8 5.72 14.65 6 0.5 10.0 12 42P/Neujmin Jul 15.9 2.01 10.70 4 9.5 15.0 14 121P/Shoemaker-Holt Sep 1.7 2.65 8.01 2 4.5 15.0 13 120P/Mueller Sep 30.2 2.75 8.43 2 12.0 10.0 18 48P/Johnson Oct 12.0 2.31 6.96 8 5.6 15.0 12 2003 K4 (LINEAR) Oct 13.8 1.02 3.5 10.0 5 130P/McNaught-Hughes Oct 23.3 2.10 6.67 2 12.5 10.0 17 78P/Gehrels Oct 27.1 2.01 7.22 4 7.1 10.0 10 69P/Taylor Nov 30.4 1.94 6.95 5 8.9 15.0 10 BAA COMET SECTION NEWSLETTER 16 THE COMET'S TALE

62P/Tsuchinshan Dec 7.9 1.49 6.63 6 8.0 15.0 11 131P/Mueller Dec 17.6 2.42 7.07 2 13.0 10.0 18 111P/Helin-Roman-Crockett Dec 27.1 3.47 8.12 2 5.0 20.0 18

The date of perihelion (T), perihelion distance (q), period (P), the number of previously observed returns (N), the magnitude parameters H1 and K1 and the brightest magnitude are given for each comet. The brightest magnitude given for 29P and 69P is that typical of an outburst.

Note: m1 = H1 + 5.0 * log(d) + K1 * log(r)

Review of comet observations for 2003 April - 2003 September

The information in this report is a the end of August 2000 by being evidently asteroidal. With synopsis of material gleaned from LINEAR. Although it only the knowledge of the clearly IAU circulars 8117 – 8212, The appeared cometary in 1986, the cometary orbit, McNaught and M. Astronomer (2003 May – 2003 identity is secure. Calculations by A. Read have now located and September) and the Internet. Note Kenji Muraoka show that the measured the object on the that the figures quoted here are perihelion distance has been Hartley follow-up plate. The 1986 rounded off from their original decreasing over the last 100 years, observations were given the published accuracy. Lightcurves with significant changes around designation P/1986 R1. [IAUC for the brighter comets are from 1934 and 1970. The next 8118, 2003 April 19] observations submitted to The significant change will be around Astronomer and the Director. A 2017, when the perihelion Comet P/2000 QD181 = 2000 XV43 full report of the comets seen distance will reduce to 1.33 AU = 1986 R1 = 1993 WU (Russell- during the year will be published from its present 1.60 AU. LINEAR), announced on IAUC in the Journal in due course. I 8118, has been given the have used the convention of permanent number 156P (MPC designating interesting asteroids 48317). [IAUC 8128, 2003 May by A/Designation (Discoverer) to 3] clearly differentiate them from comets, though this is not the IAU convention.

65P/Gunn was relatively well observed by more southerly located observers, peaking at around 12th magnitude. The observations received so far give a magnitude equation of m = 8.6 + 5 log ∆ + 6.8 log r.

R. H. McNaught, Siding Spring Observatory, reports observations of a comet found in Sept. 1986 by K. S. Russell on a 90-min exposure taken by F. G. Watson 2001 HT50 (LINEAR-NEAT) earlier that month with the U.K. could reach 11th mag at the second Schmidt Telescope. Unsuccessful of its two oppositions in 2003. attempts were made by Russell, The light curve is not very well and later by McNaught, to locate constrained by the observations the comet on the 30-min follow- made so far. up exposure by M. Hartley obtained on Sept. 25. T. B. Spahr, 2001 Q4 (NEAT) was discovered Minor Planet Center, has recently when still over 10 AU from the identified the comet with 2000 Sun and will reach perihelion next QD181, an apparently asteroidal May. Brian Marsden notes on 116P/Wild was also relatively object observed by LINEAR on MPEC 2003-R40 that the well observed, peaking at a 2000 Aug. 31 and Sept. 5 (cf. "original" and "future" barycentric similar magnitude, however the MPS 18353), and itself linked by values of 1/a are +0.000037 and - observations do not allow a well Spahr (MPO 9348) to another 0.000708 (+/- 0.000003) AU**-1, constrained magnitude equation. LINEAR discovery 2000 XV43 respectively. [2003 September 9] (observations Nov. 2000-Jan. The "original value of 1/a 2000 QD101 (156P/Russell- 2001 on MPS 23109 and 25364), suggests that this is a new visitor LINEAR) IAUC 8118 (2003 as well as to 1993 WU, recorded from the Oort cloud. Michael April 19) announced the linkage by C. S. Shoemaker et al. with the Mattiazzo gives the dates of the of a comet discovered on UK 0.46-m Palomar Schmidt orbital plane crossings as 2003 Schmidt plates in September telescope on 1993 Nov. 19 and 20 Oct 24, 2004 April 20 and 2004 1986, with an asteroid found at (MPS 397), the appearance again October 23. BAA COMET SECTION NEWSLETTER 2003 October 17

Observations in early September diameter. Recent astrometry, values of 1/a are +0.000050 and - 2003 put the comet at around 12th orbital elements (T = 2003 June 0.000590 (+/- 0.000003) AU**-1, magnitude. Alexandre Amorim, 22, Peri. = 126 deg, Node = 147 respectively. [MPEC 2003-R42, observing on September 20.31 deg, i = 145 deg, e = 0.79, P = 2003 September 9] The first value with a 0.14-m reflector x80 30.8 yr), and an ephemeris appear suggests that this is a "new" estimated the comet at 12.3 with a on MPEC 2003-R20. [IAUC comet from the Oort cloud. 0.5' coma. The comet should be a 8193, 2003 September 3] Michael Mattiazzo gives the bright object in May 2004. orbital plane crossings as 2003 Adopting a conservative 2002 O7 (LINEAR) did not reach December 25, 2004 December 25. magnitude law (7.5 log r), perihelion until September 2003, suggests a peak of around 3rd however the last observations Observations made in 2003 magnitude, whereas the standard were made in late July and it has August put the comet around 13th 10 log r gives around 0 not been seen visually since. magnitude, brightening to 12th magnitude. The observations CCD observations by Michael magnitude in September. made so far do not provide a good Mattiazzo in late September show constraint on the likely peak a faint diffuse cloud and it seems 2002 VQ94 (LINEAR) is another brightness. that it did not survive perihelion. object first noted as asteroidal and The pre-perihelion light curve identified as suspicious in the last suggests a relatively slow rate of issue. Observations made brightening, presaging things to towards the end of August 2003 come. revealed a clear coma, thus confirming the cometary nature of the object.

An apparently asteroidal object reported by LINEAR (announced on MPEC 2002-V71, where B. G. Marsden noted "whether this object is a comet or not is inconclusive", and MPS 66506) has been found to have a prominent 10" coma with a fanlike morphology spanning p.a. 180-300 deg on images taken by 2002 CE10 (P/LINEAR) As I D. Jewitt on Aug. 28.5 UT with suggested in issue 17 (2002 April) the University of Hawaii 2.2-m this object has turned out to be a telescope. Recent astrometry, the comet. Observations made in mid orbital elements below, and an August 2003 revealed the 2002 T7 (LINEAR) will reach ephemeris appear on MPEC 2003- presence of a faint thin straight perihelion on 2004 April 23 at R22. [IAUC 8194, 2003 tail some 21" long, thus 0.61 AU. The comet could be an September 3] confirming the cometary nature of impressive object in the spring the object, although any coma was and early summer of 2004, Brian Marsden notes on MPEC <6" in diameter. The further however it will then be a southern 2003-R43 [2003 September 9] observations made since hemisphere object. Making that the "original" and "future" discovery confirm the perihelion reasonable assumptions about the barycentric values of 1/a are date as June 22.1, perihelion rate of brightening suggests a +0.005297 and +0.005403 (+/- distance at 2.05 AU and the likely peak of 2nd magnitude in 0.000000) AU**-1, respectively, period as 30.7 years. There have early May, giving the opportunity suggesting that this is not a "new" been no recent planetary of viewing two naked eye comets comet from the Oort cloud. The encounters, though it approached at the same time [2001 Q4 should period is around 3000 years. to 0.6 AU from Jupiter in 1912 be around the same brightness]. December.

N. Takato, T. Sekiguchi, and J. Watanabe, National Astronomical Observatory of Japan, obtained nine CCD images with the 8.2-m Subaru telescope of the apparently asteroidal object 2002 CE10 (first reported by the LINEAR team, whose discovery observation is given below; originally announced on MPEC 2002-C83 and MPS 50101) on Aug. 22.4 UT that show a very faint, straight tail about 21" long in p.a. 212 deg; the tail is also present on shorter exposures from Aug. 21.5-21.6, 2002 Y1 (Juels-Holvorcem) when any coma as bright as the Brian Marsden notes that the faded rather more slowly than tail must have been < 6" in "original" and "future" barycentric expected, but was a southern BAA COMET SECTION NEWSLETTER 18 THE COMET'S TALE hemisphere object. The most the object to be nonstellar, with a the NEO Confirmation Page, the recent observations are from slight elongation toward p.a. 315 object was also reported to have Michael Mattiazzo who estimated deg, such that a nuclear cometary appearance by G. Hug it at approaching 11th magnitude condensation appears on the (Eskridge, KS, 0.3-m reflector; at the end of July. southeast side of a coma that has diffuse with m_1 = 16.6 on Apr. size 5".5 along a southeast- 9.4 UT and m_1 = 17.3 on Apr. Although around 50 more SOHO northwest axis and 4" along a 10.4) and by A. C. Gilmore and P. comets have been discovered over northeast-southwest axis. Images M. Kilmartin (Mt. John the last six months, few have had taken with the 1.06-m KLENOT University Observatory, 0.6-m their positions measured. At the telescope at Klet on Mar. 31.9 by reflector; diffuse on Apr. 11.6). moment there is no-one in the M. Tichy and M. Kocer show the [IAUC 8116, 2003 April 11] SOHO team responsible for object as slightly diffuse with a making the measurements and it coma diameter of 6". [IAUC 2003 G3 (SOHO) was a non may be some time before 8104, 2003 April 1] group comet discovered by John designations are announced. Sachs in C3 and C2 images on There have been some problems 2003 G1 (LINEAR) was April 4. The preferred retrograde with the spacecraft, which is past discovered by LINEAR on April orbit suggests that it was at its design lifetime. The ground 8.45. It has a perihelion distance around 30 degrees elongation control team have so far kept it of 4.9 AU. It was at perihelion in from the Sun in late April and going through technical fixes, but early February and will not early May, but no observations its days may be numbered. A brighten significantly from its were reported. replacement for the spacecraft is current 15th magnitude. not scheduled for launch before 2003 H1 (LINEAR) was 2007. SOHO now has a total of An apparently asteroidal object of discovered by LINEAR on April 669 comets, with over 100 17th magnitude, discovered by 24.38. It reaches perihelion at 2.2 awaiting designation. LINEAR on April 8.45, and AU in late February 2004. It will posted on the NEO Confirmation slowly brighten from its current Meyer Group SOHO comets 2003 Page, has been found to be 15th magnitude, perhaps reaching H5 SOHO, 2003 K5 SOHO and cometary by several CCD visual range in the autumn and 2003 K6 SOHO were discovered observers, including L. Sarounova reaching 12th magnitude at its with the SOHO LASCO and P. Kusnirak (Ondrejov), A. best. coronographs and have not been Galad (Modra), P. Birtwhistle observed elsewhere. (Great Shefford, U.K.), G. Hug An apparently asteroidal 17th (Eskridge, KS), P. R. Holvorcem magnitude object reported by 2003 F2 (P/NEAT) is a distant (0.81-m Tenagra II telescope; LINEAR on April 24.38, and periodic comet discovered by m_1 = 15.4 on Apr. 9.46 UT), and posted on the NEO Confirmation NEAT on March 27.20. It has a M. Tichy (Klet). The general Page, has been reported to be perihelion distance of 2.9 AU, a description of the comet gives a cometary on Apr. 25 CCD frames period of 16 years and will fade. coma of diameter 8"-15" and a taken by H. Mikuz (Crni Vrh, Syiuchi Nakano notes that the straight tail about 40"-90" long in 0.60-m reflector + R filter; preliminary orbit is very similar to p.a. 210-225 deg during Apr. 9.1- strongly condensed with coma that of 2001 BB50 (P/LINEAR- 10.0. The available astrometry, diameter about 20" and m_1 = NEAT) and that both objects were preliminary parabolic orbital 15.9), P. Kusnirak (Ondrejov, last at perihelion in late March elements (T = 2003 Feb. 7, q = 0.65-m reflector; "seems to be 1987. Maik Meyer notes that 4.9 AU, i = 67 deg), and slightly diffuse"), and T. Spahr based on the present orbits their ephemeris appear on MPEC 2003- (Mount Hopkins, 1.2-m reflector; separation was only 0.016 AU in G56. [IAUC 8115, 2003 April 10] faint fan-shaped tail about 5" long July 1989. Further observations toward the south). [IAUC 8122, unfortunately remove the Brian Marsden notes on MPEC 2003 April 25] possibility of splitting at the last 2003-P15 [2003 August 6] that return, although retain the the "original" and "future" Brian Marsden notes on MPEC similarity of the orbits. Nakano barycentric values of 1/a are 2003-P16 [2003 August 6] that also notes that the angular +0.000014 and -0.000372 (+/- the "original" and "future" elements of the orbit are similar to 0.000005) AU**-1, respectively, barycentric values of 1/a are those of C/1931 AN, which has a suggesting that this is a "new" +0.000745 and +0.000450 (+/- poorly defined orbit based on comet from the Oort cloud. 0.000008) AU**-1, respectively, observations made over a few suggesting that this is not a "new" days. 2003 G2 (LINEAR) was comet from the Oort cloud. discovered by LINEAR on April An apparently asteroidal object of 8.38. It has a perihelion distance 2003 H2 (LINEAR) was 20th magnitude, found by the of 1.6 AU. It is near perihelion discovered by LINEAR on April NEAT project on March 27.20, and will not brighten significantly 24.40. It is near perihelion at 2.2 and posted on the NEO from its current 17th magnitude. AU and will not brighten Confirmation Page, has been significantly from its current 17th reported as faintly cometary by a L. Manguso, Lincoln Laboratory, magnitude. The orbit is a long few observers. G. Masi reports Massachusetts Institute of period ellipse, with period around that CCD observations in good Technology, reports the LINEAR 240 years. conditions (0".9 seeing) with the discovery of a comet with a 13" Danish 1.54-m telescope at the coma visible on Apr. 9-10 Another apparently asteroidal European Southern Observatory (discovered on April 8.38 at 18th object of 19th magnitude reported on Mar. 28.3 and 29.1 UT show magnitude). Following posting on by LINEAR on April 24.40, and BAA COMET SECTION NEWSLETTER 2003 October 19 posted on the NEO Confirmation 29.33. It is near perihelion at 1.70 80247; orbital elements on MPO Page, has also been reported to be AU and will not brighten 48372) has been found cometary cometary on CCD frames taken significantly from its present 18th by C. Hergenrother, who reports a on Apr. 25 by Mikuz (diffuse with magnitude. The period is 6.1 diffuse coma of diameter 15" (and condensation and coma diameter years. The comet approached mag 18.6 within an aperture of about 20"), M. Tichy (Klet, 1.06- within 0.46 AU of Jupiter in radius 8") and a broad tail 60" m reflector; diffuse with faint tail December 2000 and approached long in p.a. 115 deg on co-added in p.a. 270 deg), and Kusnirak the planet even closer at some 900-s R-band images taken on (coma diameter about 10"). previous returns. An encounter to June 24.3 UT with the Mount [IAUC 8122, 2003 April 25] within 0.02 AU in April 2012 will Hopkins 1.2-m reflector. [IAUC reduce the perihelion distance to 8156, 2003 June 25] Further to IAUC 8122, J. McGaha 1.16 AU, though the subsequent (Tucson, AZ) reports that six two apparitions are not A/2003 HP32 (Kitt Peak) is an stacked 2-min CCD exposures particularly favourable. asteroid, of 21st magnitude, taken on Apr. 25.3 UT (0.30-m discovered by J A Larsen with the reflector) show a 6" coma and a M. Bezpalko, Lincoln Laboratory, 0.9-m telescope at the Steward 10" tail in p.a. 50 deg. [IAUC Massachusetts Institute of Observatory, Kitt Peak on 2003 8125, 2003 April 30] Technology, reports the discovery April 26.31. It is in a 5.1 year by LINEAR of a comet with a tail orbit, with perihelion at 0.56 AU Brian Marsden notes on MPEC in p.a. 270 deg on images taken and an eccentricity of 0.81. It 2003-P17 [2003 August 6] that on Apr. 29.3 UT. Following reaches perihelion at the end of the "original" and "future" posting on the NEO Confirmation August, but will remain near its barycentric values of 1/a are Page, other CCD observers have current magnitude for the next +0.026849 and +0.026146 (+/- also reported the object as few months. [MPEC 2003-H50, 0.000000) AU**-1, respectively, cometary, including G. J. Garradd 2003 April 30, 4-day orbit] The confirming that this is not a "new" (Tamworth, N.S.W., 0.45-m orbit is typical of a Jupiter family comet from the Oort cloud. reflector; slightly diffuse on most comet. It can approach to within images taken on Apr. 30.6), J. E. 0.3 AU of Jupiter and within 0.1 2003 H3 (NEAT) was discovered McGaha (Tucson, AZ, 0.30-m AU of the Earth. by NEAT on April 30.45. It was reflector; faint coma of size 5" x near perihelion at 2.9 AU and will 10" and m_1 = 17.7-17.9, aligned 2003 J1 (NEAT) was discovered not brighten significantly from its north-south, with uniform by NEAT on May 13.59. present 16th magnitude. brightness and no apparent Originally reported at 19.4, nuclear condensation or core on amateur CCD observations put it S. H. Pravdo, Jet Propulsion May 2.2), and J. G. Ries at around 17th magnitude. It Laboratory, reports the NEAT (McDonald Observatory, 0.76-m reaches perihelion at 5.1 AU in discovery on Haleakala images of reflector; 20" tail pointing slightly October. a 17th magnitude comet on April south of west on May 2.3; m_1 = 30.45 with a coma diameter of 17.7-18.0). [IAUC 8127, 2003 K. J. Lawrence, Jet Propulsion about 14" and an unresolved core May 1] Laboratory, reports the discovery of diameter about 4" or less. by NEAT of a comet on May Following posting on the NEO Orbital elements on MPEC 2003- 13.59. Following posting on the Confirmation Page, other K34, indicate that this comet NEO Confirmation Page, other observers have also reported the passed 0.07 AU from Jupiter in CCD observers reported the cometary appearance from CCD June 1929, before which q and P following total magnitudes and images, including J. E. McGaha were larger. [IAUC 8135, 2003 coma diameters: May 14.5 UT, (0.30-m reflector, Tucson, AZ; May 24] m_1 = 16.4-17.0, 10" (P. fainter outer coma of diameter Holvorcem, Tenagra II 0.81-m about 10" with a brighter core of 2003 H6 (SOHO) and 2003 H7 telescope; three co-added 120-s diameter about 5"); J. Young (0.6- (SOHO) were non group comets exposures); 15.5, 17.5, 8" (J. m reflector, Table Mountain; discovered by Rainer Kracht in Young, Table Mountain, CA, 0.6- coma diameter about 8", and 16" C2 images on April 30. They are m reflector). [IAUC 8133, 2003 tail in p.a. 250 deg, affected by clearly related to each other. May 17] cirrus clouds), and P. R. Holvorcem and M. Schwartz 2003 HT15 (P/LINEAR) An Brian Marsden notes on MPEC (Tenagra IV 0.36-m telescope, apparently asteroidal object of 2003-O37 [2003 July 30] that the near Nogales, AZ; coma diameter 18th magnitude found by LINEAR "original" and "future" barycentric 28" and m_1 = 15.4-15.7 on May on April 26.26 was found to be values of 1/a are +0.001841 and 1.47). [IAUC 8126, 2003 May 1] cometary by Carl Hergenrother on +0.001804 (+/- 0.000077) AU**- images taken with the Mount 1, respectively, suggesting that Brian Marsden notes on MPEC Hobkins 1.2-m telescope on June this is not a "new" comet from the 2003-P18 [2003 August 6] that 24.3. The comet has perihelion at Oort cloud. the "original" and "future" 2.7 AU and a period of 9.9 years. barycentric values of 1/a are It passed 0.6 AU from Jupiter in A/2003 JC11 (Kitt Peak) is an +0.000438 and -0.000114 (+/- 2001 March. It will fade. asteroid, of 21st magnitude, 0.000005) AU**-1, respectively, discovered by J V Scotti with the suggesting that this is not a "new" An apparently asteroidal object 0.9-m telescope at the Steward comet from the Oort cloud. reported by LINEAR (discovery Observatory, Kitt Peak on 2003 observation published on MPS May 1.40. It is in a 5.3 year orbit, 2003 H4 (P/LINEAR) was 78496; prediscovery LINEAR with perihelion at 1.35 AU and an discovered by LINEAR on April observations published on MPS eccentricity of 0.56. It was at BAA COMET SECTION NEWSLETTER 20 THE COMET'S TALE perihelion at the end of November in 1996 January. There are no Otterstedt in C3 images on May and will fade. [MPEC 2003-J35, significant changes to the orbit at 25. It appeared to be fading in 2003 May 6, 5-day orbit] The the next return. images from late on May 28, orbit is typical of a Jupiter family although not due at perihelion comet, though there have been no Eric Christensen, Lunar and until June 1. The preliminary orbit recent close approaches to either Planetary Laboratory, reports the suggested that it would reach 25 Jupiter or the Earth. discovery of a 15th magnitude degrees elongation from the Sun comet on May 26.18 by the in mid June, but was not reported 2003 K1 (Spacewatch) An object Catalina Sky Survey on CCD by ground based observers in the initially reported as asteroidal by images taken with the 0.7-m Southern Hemisphere. It was not Spacewatch has been found to be Schmidt telescope. Following favourably placed for discovery cometary by other observers, posting on the NEO Confirmation prior to perihelion. including some using the 0.41-m Page, many observers noted the OAM relector at Costitx, obvious cometary nature of the 2003 K4 (LINEAR) An Mallorca. It is past perihelion and object on CCD images taken apparently asteroidal object of will fade from 18th magnitude. during May 27.1-27.2 UT, 18th magnitude found by LINEAR including R. Elliot (Fall Creek, on May 28.38 has been found to An object of 20th magnitude WI; coma diameter about 10"), P. be cometary by other observers. initially reported as asteroidal by R. Holvorcem and M. Schwartz The preliminary orbit suggests J. A. Larsen on CCD images (near Nogales, AZ; coma that it is a distant object with obtained with the 0.9-m diameter about 35", with a 30" tail perihelion at 8.5 AU in Spacewatch reflector on May in p.a. 106 deg), J. Young (Table September, however other, more 23.38 was posted on the NEO Mountain, CA; 10" coma and a interesting orbit solutions were Confirmation Page. CCD images very faint 40" tail in p.a. 115 deg possible according to Maik taken by A. Lopez and R. Pacheco with a slight curve halfway along Meyer. New elements issued on (Mallorca, 0.41-m reflector) on its length to p.a. 130 deg), and J. MPEC 2003-L08 [2003 June 3] May 23.9 UT showed cometary McGaha (Tucson, AZ; coma confirmed the more interesting appearance (and m_1 = 18.2- diameter 12", with slight nuclear orbit, and the latest put perihelion 18.6). A. E. Gleason found the condensation and a 6" tail). at 1.02 AU on 2004 October 13.8. coma to be quite obvious on May [IAUC 8136, 2003 May 27] The apparition circumstances are 24.3 images taken with the 1.8-m not particularly favourable, Spacewatch II reflector at Kitt It has been noted by numerous however the comet could reach 5th Peak, and Larsen found a 10" individuals that the preliminary magnitude. By early August it had coma on Spacewatch I images orbital elements of comet C/2003 brightened to 16th magnitude taken on May 24.4. [IAUC 8135, K2 (cf. IAUC 8136) place it close (CCD). The comet may come 2003 May 24] to the position of an unconfirmed within visual range from October object found on SWAN ultraviolet this year and be visible until the 2003 K2 (P/Christensen) An SOHO website images and end of the year when it enters object discovered by the Catalina reported to the Central Bureau on conjunction. sky survey on May 26.18 was Apr. 14 by X.-m. Zhou (Bo-le, quickly confirmed as cometary. It Xin-jiang, China). Measurements An apparently asteroidal object passed perihelion at 0.55 AU in of the object on six dates, Apr. 5- found by the LINEAR survey on April, but is intrinsically faint. It 19, were forwarded to the Central May 28.38, posted on the NEO was visible on SWAN imagery Bureau by Zhou (via D. H. Chen), Confirmation Page, has been and at brightest probably reached by M. Mattiazzo, and by S. found to show a round coma of th 10 magnitude; it seems likely Hoenig; the positions differed diameter 5"-7" (m1 = 17.5) on that it was the object reported in considerably, due to the poor CCD images taken by J. Young SWAN imagery between April 5 resolution of SWAN (uncertainty on May 29.5 and 30.4 UT with to 19, but which was not on the order of 1 degree). Two the 0.6-m reflector at Table confirmed visually due to low search ephemerides based on Mountain. J. McGaha, Tucson, elevation and poor elongation various positions were circulated AZ, reports that three stacked, 2- from the Sun. It will fade from by the Bureau to numerous visual min CCD images, taken on May 14th magnitude. Its elongation and CCD observers in the hopes 29.4 with a 0.30-m reflector, show remained relatively small and it of optical confirmation, but the a 3" nuclear condensation and a was not very favourably placed searches (undertaken during the 6" coma that is offset to the for observation. As astrometric last week of April by Zhou, A. northeast. [IAUC 8139, 2003 May observation accumulated there Hale, Mattiazzo, Y. Kushida, and 30] was increasing evidence that it Y. Ezaki) revealed nothing to as was a short period comet, with a faint as mag 14.5. The following Brian Marsden notes on MPEC period between 12 and 17 years improved parabolic orbital 2003-R44 [2003 September 9] and perihelion distance around 0.6 elements for C/2003 K2 (from that the "original" and "future" AU. These indications from orbits MPEC 2003-K49) indicate that barycentric values of 1/a are by Muraoka and others were the search-ephemeris positions in +0.000020 and -0.000199 (+/- confirmed on IAUC 8145 [2003 late April for the SWAN object 0.000014) AU**-1, respectively, June 7] which gave an orbit with were no closer than about 2.5 suggesting that this is a "new" period of 6.5 years. Further orbit degrees from C/2003 K2. The comet from the Oort cloud. Such computations by Muraoka, Stoss comet might be of short period. comets often brighten relatively and others have revised the orbit [IAUC 8138, 2003 May 30] quickly at first, so that we should and the latest orbit gives P as 5.75 not necessarily expect a good years and q at 0.55 AU. The 2003 K3 (SOHO) was a faint non display at perihelion. comet passed 0.8 AU from Jupiter group comet discovered by Heiner BAA COMET SECTION NEWSLETTER 2003 October 21

2003 KV2 (P/LINEAR) An there have been no recent close and the eccentricity is 0.9814155 asteroidal object of 18th approaches to either Jupiter or the showing that this is not a "new" magnitude discovered by Earth. It is a potentially hazardous comet from the Oort cloud. LINEAR on May 23.16 has been asteroid passing 0.026 AU from found to be cometary by other Earth at the ascending node. A/2003 MT (Kitt Peak) is an observers. It reaches perihelion on asteroid, of 19th magnitude, July 10 at 1.06 AU and has a 2003 L1 (P/Scotti) Jim Scotti discovered by M T Read with the period of 4.85 years, the third discovered this faint comet in 0.9-m telescope at the Steward shortest amongst currently extant Spacewatch data. Further Observatory, Kitt Peak on 2003 comets. It passed within 0.55 AU prediscovery images were found June 23.20. It is in a 5.3 year of Jupiter in February 2001, in Palomar NEAT data from 2002 orbit, with perihelion at 1.22 AU before which the perihelion April. The comet is three months and an eccentricity of 0.60. It will distance was somewhat larger. It past perihelion, which was at 5.0 be at perihelion in early August will not get much brighter than its AU. The period is 17.3 years. It but will fade. [MPEC 2003-M42, present magnitude. The will fade. 2003 June 24, 1-day orbit] The preliminary orbit given for the orbit is typical of a Jupiter family comet on MPEC 2003-K27 was J. V. Scotti, Lunar and Planetary comet, though there have been no not particularly cometary, Laboratory, University of recent close approaches to either whereas that for 2003 KU2 Arizona, reports the discovery of Jupiter or the Earth. looked more promising. a 20th mag comet on CCD images taken with the Spacewatch 0.9-m 2003 O1 (LINEAR) An 18th Another apparently asteroidal f/3 reflector at Kitt Peak on June magnitude comet was discovered LINEAR object found on May 4.21, showing a coma of diameter by LINEAR on July 20.13. The 23.16, announced on MPEC 6" and a faint tail about 0'.62 long provisional orbit (given to rather 2003-K27 as 2003 KV_2 (see also in p.a. 273 deg. Images taken by high accuracy for only a three day MPEC 2003-K38 and 2003-K47), A. S. Descour on June 5.3 UT arc) suggested that it was a distant has been found cometary on R- with the 1.8-m f/2.7 Spacewatch object some way from perihelion band images taken by C. reflector also show a tail, and at 4.5 AU. Nick James reported Brinkworth and M. Burleigh on June 7.2 images by Scotti with the imaging it on July 20.97 in a May 28.9 and 29.9 UT with the 1- larger instrument show the tail rather crowded field, with Peter m Jacobus Kapteyn Telescope on 0'.30 long in p.a. 273 deg. [IAUC Birtwhistle imaging it on July La Palma (communicated by A. 8145, 2003 June 7] 20.95 and Stephen Laurie on July Fitzsimmons), in which the object 20.96. Further observations shows a tail about 4"-5" long in Clearly diffuse NEAT images of confirmed the distant orbit, p.a. 125 deg and a small coma this comet, taken with the though with perihelion at 6.8 AU that is somewhat larger than the Palomar 1.2-m Schmidt telescope in March 2004. surrounding field stars. The on three nights in 2002 April, preliminary orbit shows a passage were identified and measured by An apparently asteroidal object 0.55 AU from Jupiter in Jan. M. Meyer. Additional astrometry reported by LINEAR, and posted 2001, before which the perihelion and the following orbital elements on the NEO Confirmation Page, distance was somewhat larger. (MPEC 2003-M21) confirm the has been found to have cometary [IAUC 8139, 2003 May 30] suspicion (cf. IAUC 8145) that appearance on CCD images taken this is a short-period comet. by P. Kusnirak (Ondrejov; 0.65-m A/2003 KP2 (LINEAR) is an [IAUC 8153, 2003 June 19] f/3.6 reflector; well-condensed asteroid, of 19th magnitude, condensation and a faint 20" tail discovered by LINEAR on 2003 2003 L2 (LINEAR) was toward the southeast) and by P. May 22.34. It is in a 4.53 year discovered by LINEAR on June Birtwhistle (Great Shefford, U.K.; orbit, with perihelion at 0.82 AU 12.33. It will reach perihelion at nuclear condensation of diameter and an eccentricity of 0.70. It will 2.9 AU in mid January 2004 and about 6" with a faint, short, broad be at perihelion in mid October will brighten a bit from its current tail about 15" long in p.a. 139 and will brighten a little. [MPEC 18th magnitude. deg; mag 17.3-18.2). [IAUC 2003-R63, 2003 September 13] 8170, 2003 July 30] The orbit is typical of a Jupiter An apparently asteroidal object family comet, though there have found by LINEAR, and posted on Brian Marsden notes on MPEC been no recent close approaches the NEO Confirmation Page, has 2003-R09 [2003 September 2] to Jupiter. It will pass 0.18 AU been found to be cometary on that the "original" and "future" from the Earth in early October. CCD images taken by S. Sanchez, barycentric values of 1/a are R. Stoss, and J. Nomen (Mallorca, +0.000225 and +0.000217 (+/- A/2003 KU2 (Kitt Peak) is an 0.30-m f/9 reflector; 10" coma on 0.000018) AU**-1, respectively, asteroid, of 20th magnitude, June 12.95 UT) and by S. Gajdos suggesting that this is probably discovered by A Tubbiolo with (Modra, 0.6-m f/5.5 reflector; not a "new" comet from the Oort the 0.9-m telescope at the Steward diffuse with coma diameter about cloud. Observatory, Kitt Peak on 2003 5" on June 13.97; m_1 = 18.0). May 22.29. It is in a 4.6 year [IAUC 8151, 2003 June 14] 2003 O2 (P/LINEAR) A 19th orbit, with perihelion at 0.80 AU magnitude comet was discovered and an eccentricity of 0.71. It will Brian Marsden notes on MPEC by LINEAR on July 29.38, be at perihelion at the end of 2003-R45 [2003 September 9] although other CCD observers October and will brighten a little. that the "original" and "future" estimate it at 17th magnitude. [MPEC 2003-K26, 2003 May 24, barycentric values of 1/a are Peter Birtwistle imaged it on July 2-day orbit] The orbit is typical of +0.006356 and +0.006809 (+/- 31.04. It showed a surprisingly a Jupiter family comet, though 0.000011) AU**-1, respectively, long tail, perhaps suggesting a BAA COMET SECTION NEWSLETTER 22 THE COMET'S TALE

recent outburst. Further observers estimate it a little A/2003 RW11 (Table Mountain observations confirmed the short brighter. The comet is nearly a Observatory) is an asteroid, of period nature of the orbit, with year past perihelion and will fade. 19th magnitude, discovered by J perihelion at 1.5 AU in early The perihelion distance is 4.3 AU Young with the 0.6-m telescope at September and a period of 8.7 and the period around 22 years. It Table Mountain Observatory on years. It has had no recent passed 0.8 AU from Jupiter in 2003 September 15.47. It is in a planetary encounters. It will not 1911 May. 5.1 year orbit, with perihelion at get much brighter than at present. 0.46 AU and an eccentricity of An apparently asteroidal object 0.84. It was at perihelion in mid M. Bezpalko, Lincoln Laboratory, reported by NEAT (Palomar June. [MPEC 2003-S03, 2003 reports the LINEAR discovery of discovery observation originally September 16, 1-day orbit] The a comet, showing a tail posted on the NEO Confirmation orbit is typical of a Jupiter family approximately 42" long in p.a. Page, then assigned the comet, and it can approach to 230 deg. Other CCD observers designation 2003 QX_29 on within 0.5 AU of Jupiter and 0.08 report mag 16.9-17.9 and a tail of MPEC 2003-Q33; observations AU of the Earth. up to 6' long in p.a. 245-250 deg on MPS 93475-93476) has been on July 30-31 (including S. found to have cometary 2003 S1 (P/NEAT) A 19th Sanchez, R. Stoss, and J. Nomen appearance on CCD images taken magnitude comet was discovered at Mallorca; R. Trentman and R. by I. Griffin and S. G. Huerta by NEAT on September 23.60, Frederick at Louisburg, KS; and (Cerro Tololo 0.9-m reflector, with some LINEAR prediscovery P. Birtwhistle at Great Shefford, Aug. 31.1 UT; visible coma of red images found from September 4.3 U.K., who also noted a 9" central mag 18.0-19.4 with FHWM = and 20.3. Peter Birtwhistle was condensation of mag 17.9, adding 2".3-2".6 in raw 300-s images, amongst those making confirming that the tail was very diffuse and while stacked 10-exposure image images. The comet reaches wide). [IAUC 8172, 2003 July 31] shows a fan-shaped tail at least perihelion next March, though 17" long in p.a. 58 deg) and by J. will remain near its present 2003 O3 (P/LINEAR) A 19th Young (Table Mountain 0.6-m brightness. The perihelion magnitude comet was discovered reflector, Sept. 1.2; 3" coma, distance is 2.6 AU and the period by LINEAR on July 30.39, slightly elongated in p.a. 260 deg, around 9.7 years. It passed 0.2 although other CCD observers with a 16" curved tail starting in AU from Jupiter in 1972 October. estimate it at 18th magnitude. It p.a. 243 deg; possible slight was confirmed as cometary by brightening in the tail at a point 2003 S2 (P/NEAT) An 18th Peter Birtwhistle amongst others. 4"-5" from the coma edge). J. magnitude comet was discovered The comet reached perihelion at Ticha subsequently reports that by NEAT on September 24.61, 1.25 AU in mid August and will Klet images from Aug. 23.9 show with some LINEAR prediscovery fade. It passed 0.5 AU from the object to be slightly diffuse, images found from September Jupiter in 1956 July and the while on Aug. 24.9 it exhibited a 19.36. Peter Birtwhistle was period is 5.5 years. 8" coma. Astrometry, orbital amongst those making confirming elements (T = 2002 Oct. 17.3 TT, images. The comet reached An apparently asteroidal object Peri. = 37.1 deg, Node = 264.9 perihelion in July and will fade. reported by LINEAR, and posted deg, i = 11.4 deg, equinox 2000.0, The perihelion distance is 2.3 AU on the NEO Confirmation Page, e = 0.445, q = 4.311 AU, P = 21.6 and the period around 8.6 years. has been found to be apparently yr), and an ephemeris appear on The preliminary orbit suggests cometary on CCD images taken MPEC 2003-R14. [IAUC 8192, that the comet passed 0.25 AU by P. Birtwhistle (Great Shefford, 2003 September 2] from Jupiter in January 1958. U.K., 0.30-m reflector; very faint This is NEAT’s 37th comet. tail about 10" long in p.a. 2003 R1 (LINEAR) was approximately 270-280 deg on discovered by LINEAR on 2003 S3 (LINEAR) was July 31.10 and Aug. 2.08 UT; September 2.37. It reached discovered by LINEAR on mag 18.1 and coma diameter perihelion at 2.2 AU in early July. September 27.38. It is a distant about 5" on Aug. 2.08), by J. It will not brighten significantly object near perihelion at 8.2 AU. Ticha and M. Tichy (Klet, 1.06-m from its current 19th magnitude. It will not brighten significantly KLENOT telescope; diffuse with from its current 19th magnitude. a wide tail in p.a. 260 deg on Aug. An apparently asteroidal object 3.01), and by J. McGaha (near reported by LINEAR, and posted 2003 S4 (LINEAR) is LINEAR’s Tucson, AZ; possible tail spike 5" on the NEO Confirmation Page, 120th – a distant object. long in p.a. 300 deg on Aug. 3.38 has been reported to have with a 0.30-m reflector; possible cometary appearance on CCD For the latest information on fan-shaped tail 5" long in p.a. 260 images obtained by J. Ticha and discoveries and the brightness of deg on Aug. 5.33 with a 0.62-m M. Tichy (Klet, 1.06-m KLENOT comets see the Section www reflector). The preliminary orbital telescope; slightly diffuse object page: http://www.ast.cam.ac.uk/~jds or elements indicate that the comet with a 6" coma on Sept. 5.08 UT, the CBAT headlines page at passed 0.3 AU from Jupiter in and asymmetric coma to the http://cfa- Nov. 1979. [IAUC 8174, 2003 northwest on Sept. 6.05); and by www.harvard.edu/cfa/ps/Headlines.html August 5] J. E. McGaha (Tucson, AZ, 0.30- The Comet's Tale is produced by m f/10.0 Schmidt-Cassegrain th Jonathan Shanklin, with thanks to 2003 QX29 (P/NEAT) A 20 reflector; 3" coma with a fan- the British Antarctic Survey and magnitude asteroid was shaped tail 8" long in p.a. 320 deg the Institute of Astronomy, discovered by NEAT on August on Sept. 6.39). [IAUC 8195, 2003 Cambridge for the use of 23.28. It was found to be September 6] computing facilities. E&OE. cometary and some CCD BAA COMET SECTION NEWSLETTER 23 THE COMET’S TALE

BAA COMET SECTION NEWSLETTER