The database of comets in Starry Night is updated regularly to reflect comets currently near enough and bright enough to be observable. No attempt is made to include all comets, past and present, because that would slow down the performance of the software. You can, of course, add any comets you want to the database by entering their orbital elements "New Comet Orbiting Sun" under the File menu. Comet elements may be obtained from the Minor Planet Center.
Starry Night Software Support
Starry Night looks for a file called Comets.txt when it starts up and, if found, will load the positions of the first 100 comets found in this file. Since the orbital elements of comets are constantly changing it is a good idea to update this Comets.txt file from time to time. The Comets.txt file contains positions of comets calculated by the Planetary Services Division of the Smithsonian Astronomical Observatory in Cambridge, Massachusetts.
To update Starry Night\'s comet data: open theComets.txt file in your web browser by clicking theComets.txt link above. Select "Save As..." from your browser\'s File menu and replace the Comets.txt file in Sky Data folder. Be sure to save the file as "text" and make sure the C in Comets.txt is a capital letter C.
If you are tracking a specific comet that you want to add to Starry Night try using the Orbit Editor. The Orbit Editor is a good tool for learning about celestial mechanics. Celestial mechanics is usually passed over in introductory Astronomy courses, because the mathematics and time needed to grasp orbital concepts is just too involved for most students. Starry Night provides an interactive simulator where the orbital elements of an object can be changed in a visual manner making a complex subject understandable and, dare we say it, fun.
For more information about adding a new planet, asteroid, satellite, moon, or comet to Starry Night see "Using the Orbit Editor".
The Minor Planet Center's orbital elements for 'unobservable' comets in Starry Night format can be searched here:
See also: Guide to adding comets by writing data directly to the comet.txt file