Examine the object carefully. Is it symmetrical? If it is, chances are it’s a galaxy. Does it have a mottled, circular appearance? Maybe it’s a globular cluster. Switch to higher magnifications to try and see if you can resolve the individual stars. Does the "comet" shift in position when you move the telescope around? It could be just a "ghost image" (internal reflection) in your telescope optics. Even if the object shows an obvious tail, make sure it isn’t something like Hubble’s variable nebula. According to the International Astronomical Union’s Central Bureau for Astronomical Telegrams (CBAT), the world’s clearinghouse for astronomical discoveries, more than 90 percent of all first-time comet reports turn out to be spurious.
Check its position (in right ascension and declination) on a suitable star atlas or sky-charting program. Make sure there are no known galaxies, star clusters, or nebulae plotted in that location. (If you’re using a sky program, don’t forget to have its limiting magnitude set faint enough.)
Record the object's position relative to the background stars. If the suspect doesn’t show any movement within an hour, it’s probably not a comet.
Get a friend or a trusted member of your local astronomy club privately to confirm your find visually, photographically, or with a CCD camera. Multiple observations within a single night or on a second night are highly recommended.
Check websites for lists of newly discovered comets or returning periodic ones to see whether you have picked up a known comet.
- the exact date and time of your observation in Universal Time
- your observing site and telescope used
- the object’s precise coordinates (in equinox 2000.0)
- its rate and direction of motion
- its estimated magnitude
- its physical description
Don’t forget to include your name, postal address, phone/fax, and e-mail.
Good luck, and happy hunting!