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This is an informal and incomplete (I have to set limits to my writings!) report of this congress made by an amateur astronomer  (hence not a specialist as most of the participants) and this can give an impression of what a typical (well maybe not so typical!) layman has collected from this session.



This workshop has been perfectly organized by Nicolas Biver and I thank him for that; more than 50 attendees from all parts of our planet were registered. This was headed by the SAF (Société Astronomique de France) and was held in the great room of the so called "Castle (grande coupole).








The meeting started by a special salute to Nicolas : a Minor Planet discovered by Milos Tichy and Jana Ticha has been given the name "Biver" as gratification for all his efforts in his field of work; here are a few photos from this ceremony :




Milos handing out the document to Nicolas














                                                                                     Brian Marsden (MPC boss) explaining the orbital data of "his" rock

The official name of this minor planet is  (26969 Biver) : 1997 SE  discovered on 20Sept 1997.




Patrick Guibert president of SAF during his opening and welcome lecture:












Then Garry Kronk entertains us about his passion about comets he got since he was a young boy and explain us his master work about comets : "Cometography" he is publishing in 4 listing all the comets seen and registered by man since the beginning (of intelligent man, not of comets!!), observations and characteristics since ancient times (Vol 1) till present time , Vol 2 (the first 20 years of the 19th century), vol 3 and 4 are in preparation.

It is a gigantic work that allows respect and consideration from all of us.

( )






Our young friend, Sebastian Hönig from Heidelberg shared with us his passion as "comet hunter" and especially talked about the "enemies" of amateurs  : LINEAR et NEAT etc.. these automatic observatories which detect tireless and painless and soulless these dirty snowballs from space.

He pointed out an interesting fact : in which portion of the sky we, amateurs should look and observe, where we are not in competition with these automatic observatories.





Then Milos Tichy from the Czech Republic was  on stage, he developed a software package allowing analyse of images and permitting the determination whether it is  a comet or not. (see his website :

This is called the KLENOT project from "his"  observatory Klet

Milos is a painstaking observer and discoverer : he confirmed 60 comets and discovered one.









Panel discussion

From left to right :

S Hönig; M Meyer

B Marsden; M Tichy

G Kronk










After walking through the superb park, we had lunch at the Observatory's cafeteria 





Our friends from SAF in great discussion!






















To the left Milos Tichy and ,Jana Ticha, JP Martin (humble author of this report) sitting close to B Marsden and trying to enjoy this wonderful wine (!!!) to the right


After lunch break, Brian made his speech about the need for and use of astrometrics observation of comets and about the organisation of the MPC (Minor Planet Center : ) as well as about the update of cometary's observations (  ) or NEO ( ) and the observation and confirmation procedures ( )

Circulars are published weekly and the  ICQ (International Comet Quarterly) quarterly.

For newcomer or non specialists it is absolutely mandatory to have a look at the initiation page especially if you think that you have discovered a comet (who knows, you may be right!)



Dan Green stressed the fact that photometry should be the domain in which professional astronomers are requiring most information. Very few data are available about these photometric aspect of observed comets. He urged amateur astronomers to go in that direction.




Charles Morris (from ICQ and Dream Weaver Observatory) continues the show and explains the main parameters acting on photometric measurements and the pros and cons of the actual generation of CCD.  , greta hopes in the new CCD types such as  KAF 1602E from Kodak

He also thinks that amateurs should invest more observation time in comet photometry field where data are very scarce..









Evening reception at l'Observatoire de Paris (unfortunately, I could not join the party because of the preparation of the Venus Transit of Tuesday) but I know that everything went well.

(see their site : )









Saturday was also a busy day, and I am also obliged to cut a part of my commentaries in order not to be too boring.


Jacques Crovisier, radio astronomer explained us the difficulty to observe directly water out gassing from comets, we have to rely on other indicators such as spectral values for radicals : H, H and O which are detected by radio telescope (for instance the 18cm radiation of the OH)

Very interesting presentation (see his very complete paper at  : )

Water out gassing are evaluated for some comets and for instance : 2002 T7 LINEAR at 2 1028 /sec

Jacques Crovisier indicated also to the audience an empirical law establishing a correlation between the flux of OH out gassing and the visual magnitude of comets



Then came the part in which I was most interested in : the famous  Deep Impact project from NASA. Sending a probe to the Tempel 1 comet and try to impact it next year. This is really a challenge


The Principal Investigator of this project, Dr Mike A'Hearn was here to inform us about the latest developments. This ambitious project should help us understand the exact internal layer structure of this type of comets, in order to be able one day (very remote I hope!) to change the course of a dangerous comet targeted to the Earth and if Bruce Willis is not available on that day!

The probe has two parts : the impactor (delivers 5T of TNT of energy with its 50% mass of copper) and the fly by part (30cm telescope and spectrometer)

Please consult the University of Maryland site on that fabulous project, you will not regret it!!


Launch is foreseen for December 2004 for an arrival on July 4, 2005

Here are two slides from his presentation :



















Various impact scenarios have been presented such as : crater formation, split nucleus, through nucleus scenario!, burry into nucleus (!!)

The very impact moment should be imaged by the flyby probe cameras and by terrestrial and space observatories, in order to learn as much as possible from this event.

IMPORTANT : amateurs are requested to participate to the experiment, please consult details on the web page








Lunch break was also used for photographing (bright sun) our comet discoverers group













The afternoon was mainly dedicated to the determination of the so called photometric coefficient Af[Rho] linking albedo, dust activity and diaphragm diameter

Our Italian friends (Giannantonio Milani from the CARA project was there and presented his results) have a very good site with thorough explanations on this factor :


Philippe Morel from SAF explained us the standard codification  (ICQ) of cometary's observation (necessary for a non specialist like me) he developed an Excel spreadsheet to help us to get the right encoding. See also the MPC website on the ICQ codification :









One of the last lecture summarizing the photometric session was from our Antarctic Hero Jonathan Shanklin, born comet hunter from the BAA.


Jonathan is a meteorologist ozone specialist; go and see his very informative site on the ozone hole, it is very helpful to understand our present world:


each topics is very deeply analysed and explained (I know we are far from comets, but who knows….?)


Then came the congress conclusion by the SAF members:


Nicolas Biver (in the background)

Georges Saccomani secretary of SAF

Thanking all participants for coming and inviting to the next workshop in 5 years in Japan










Helène Reyss, in charge of SAF finance

Whose work for this workshop has ensured a smooth organisation during these few days.







The end of the afternoon was dedicated to the Meudon observatory:

The Meudon Observatory has been built by the French astronomer Jules JANSSENin 1876


We start the visit by the Grand Sidérostat from Foucault used to follow the sun, it has been demonstrated to the public for the first time during the international exhibition of 1900.

The 800mm mirror is actuated by a motor and is mounted on a bath of quicksilver for a good vibration isolation








Then came the Great 18m Dome (la grande coupole) which holds the greatest refractor from Europe, the third in the world, this represents the achievement of what we can do with refractors.
















It is composed actually of two refractors : one (visual type) of 83cm diameter and 16m focal length and the other (photographic mode) of 62cm and 15.90m of focal length.

This "grande lunette" (great refractor) has been built in 1893.


It played an enormous historical role as this is with this refractor that Antoniadi gave a stop to the dream of the Mars "channels" in 1909, the little green men were peacefully "genocided" on that day!!.













The great dome is in a very bad shape due to the 1999 tempest.


More details in this article from  "Ciel et Espace" on this astronomic wonder (in French) let us all save the grande lunette de Meudon!!!!



See also :







We finished the visit by the 1m refractor used mainly for the moon, planets and comets.





















Finally, dear Reader, I am done, these were my impressions and thoughts about these two days in Meudon with the best guys in the world for comets.


Bravo again for all the people who organised this congress.


Jean Pierre MARTIN


NOTE : Photos in this report are of low resolution type in order to be loaded quickly on the Internet, in case of or many of these photos are of interest to you, do not hesitate to contact me, I will e-mail the one you want directly and with a high resolution. These photos can be used freely


CONTACT ME       HERE : telescope.gif 


Clear Sky to all


PS : the transit of Venus was observed by us in Plaisir (vicinity of Versailles) and had a great popular success (hundreds of visitors, mostly young people, this is a good sign for the future). A complete report on this event with photos will be put on line in a few days.


Present from Vega Astronomy Plaisir : one photo of Venus transiting the sun on June 8, 2004 @ 09:54 UT