|
Description
The GC is a catalog of standard positions and proper motions for (all) stars brighter than magnitude 7, extending from the north to south celestial poles. Several thousand additional stars promising to yield reasonably accurate proper motions were included in the catalog. The objectives of the work were to provide standard positions and motions of accuracy limited only by the character and abundance of the observational material upon which the data were based and thus to provide a rich supply of data to promote research in many astronomical fields. The machine version of the GC includes both The Henry Draper Catalogue and Durchmusterung identifications for all stars, although the published GC contains only one or the other. The 1985 version corrected many errors present in a previous machine version and included probable errors for the positions and centennial proper motions (not present in the previous version). In this version decimal points have been aligned for all but a very few of the secular variations and third terms. These quantities are given with the same precision as in the printed catalog, and the coded spectral types have been omitted. The following quantities are included in the machine but not the published version: galactic coordinates and DM numbers. The following data are in the published but not the machine version: centennial increments of proper motion in right ascension and declination, probable errors of the right ascension and declination at 1950.0, and remarks. The documentation supplied with the machine catalog gives a byte-by-byte format description, indigenous catalog characteristics, code explanation tables, and changes incorporated to produce this and previous Astronomical Data Center versions.
|
