APPENDIX III - A Catalogue of all the Comets whose Orbits have hitherto been computed

Summary

A new comet having been discovered, the first thing an astronomer does, is to obtain 3 observations of it, whereby he may compute the elements of the orbit. He then examines a catalogue of comets, to see if he can identify the newly-found stranger with any that have been before observed. The value of a complete catalogue is therefore obvious, and as nothing of the kind has, as far as we are aware, been published for some years, we have been led to compile a new one.

In the preparation of the following, care has been taken that only the most reliable orbits that were to be obtained should be inserted, the general rule being to prefer the one which was derived from the longest arc, other things being satisfactory. Among the authorities consulted may be mentioned Pingré, Hussey, Olbers, Cooper, Hind, Arago, and others.