Development of a catalogue of galactic x-ray sources
Abstract
Proper motions of stars may be obtained with reasonably good accuracy from the combined entries of several old position catalogues. The procedure followed by Dr. Gale W. Cleven (1962) in his dissertation at Georgetown Observatory (Georgetown Observatory Monograph No. 18) involved two steps, one, in which the original published positions were reduced to the system of the General Catalogue with the aid of formulas given in the GC; in the second step the positions for each catalogue were reduced to a uniform precession constant and brought forward to a single epoch (1900.0). The individual positions at the common epoch were assumed to differ only by the accumulated proper motion. With the advantage of large computers with which the corrections can be applied quickly and the results tabulated automatically, this procedure can provide proper motions that will add significantly to the available data for dynamical and statistical studies. Granted that old position catalogues are unsuitable for systems comparable to the FK3, FK4 and later systems, the 1456 proper motions obtained by the above procedure for a small area of the sky in Orion have an accuracy comparable with values given in the GC and Yale Catalogue.
- Publication:
-
The Astronomical Journal
- Pub Date:
- June 1967
- DOI:
- 10.1086/110278
- Bibcode:
- 1967AJ.....72..597O