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The SOHO-500 Comet Contest
The SOHO-500 Comet Contest
3 May 2002
(Source: European Space Agency)

Contest Objective

Predict the perihelion date and time of SOHO-500.


  • The contest is open to anyone, anywhere, except to Doug Biesecker and Derek Hammer.
  • Entries must be e-mailed to Doug Biesecker ( no later than the end of the day May 31st, 2002 EDT (0400 UT, June 1). Valid entries must include your name, your e-mail address, and the date and time, including year, month, day and time of day in UT. Only one entry per person will be accepted.
  • In the case of the 500th comet being an archive discovery, then the discoverer is also not eligible, but the closest guess still wins.
  • Guesses will not be revealed publicly until the entry period has closed. However names of those who have submitted guesses will be posted to verify that an entry has been received on your behalf.
See the web site

Note: The web site will be updated as often as possible, but due to travel engagements, in the next few weeks, there will be delays.


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Other Notes & Disclaimers

Determination of the SOHO comet numbers is entirely at the discretion of Douglas Biesecker. He assigns the numbers in order of discovery. These numbers are not an official product of any recognized astronomical body. However, they are a very convenient way to refer to the various comets and to keep track of the total number.

Definition of an archive discovery: This is also at the discretion of Douglas Biesecker. If a comet is reported more than 36 hours after it is first visible in the data (and there are no large gaps in the data), then the comet will be designated as an archive claim. In cases of ambiguity, the 36 hour rule will begin at the time when an average observer might be expected to have been able to find the comet.

Neither ESA, NASA, or any other institution associated with SOHO is involved with the adjudication of claims or providing the prize. The contest is designed to increase the public's awareness of SOHO's discoveries and demonstrate the ease of accesibility of scientific data sets by the general public.

Links & Tips


Tips: Possible Strategies
  1. Estimate the number of comets per year and extrapolate.
  2. Refine your estimate by looking at the monthly variation in the rate of discoveries.
  3. Consider the chance that the discovery will be an archive claim.
  4. Guess.
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Last Updated: 6 May 2002