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Comet Ephemerides

Comet Ephemerides
Local Home Page for Chernogolovka

File original: © Charles S. Morris / csm@encke.jpl.nasa.gov

Local pages are mentioned by

Last Updated: 4 March 1997

There is a new IAU numbering scheme for periodic comets observed at more than one apparition. (This is something like the numbering scheme for asteroids.) These are links to the official (IAU) lists -- as a function of name and as a function of number.

Given below are ephemerides for relatively bright comets. The comets selected are those currently under observation by the undersigned. It is not intended to provide ephemerides for all comets. The ephemerides will be updated and posted as time permits. This page is not intended to be a fast notification service. There are other sources for discovery notification.

General Comments

In general, daily ephemerides are provided. Time is given as the year, month, day, and hour in UTC (1994 8 2 0 = 1994 August 2 at 0 hours UTC = 5pm PDT [8pm EDT] on August 1, 1994). The Right Ascension (RA) is given in hours and minutes and the Declination (DEC) is given in degrees and minutes. (If you don't know what RA and DEC are, these ephemerides won't be of much use to you.) The comet's total magnitude (m1=TMAG on the ephemeris output) is calculated from a formula and could be in error by a magnitude or more. Note that the m1 value represents the stellar brightness of the coma. If the comet's coma is large, the comet may be less apparent than might be expected from the total magnitude. (Coma diameters of 10 arc-minutes [about a third the diameter of the moon] or more are not that unusual.)

To save time, I will only provide ephemerides in 2000 coordinates. If there are sufficient requests, I may bring back the 1950 ephemerides

Note: most the orbital elements used to create these ephemerides were obtained from the International Astronomical Union Circulars (IAUCs), Minor Planet Circulars (MPCs) or the ICQ Comet Handbook. Other ephemerides have been provided directly by Dr. Donald Yeomans, JPL. The orbital elements used are listed in each ephemeris

All the files are in plain text ASCII. Note: Epoch 2000 orbital elements are always used. These ephemerides were generated using a program by M. Keesey and D. Yeomans, JPL. I intend to simplify the output of this program in the near future. Note that definitions of each term is given at the bottom of the ephemeris.