SAO Star Catalog

WCSTools Catalogs
These files contain the entire SAO catalog of 258,996 stars, including B1950 positions, proper motions, magnitudes, and, usually, spectral types in a locally-developed binary format described below. While the SAO catalog is more or less complete to V=9, with 4,503 stars fainter than V=10, the PPM catalog is fairly complete to V=9.5, with 102,672 stars fainter than V=10 and 22,395 stars fainter than V=11.

SAO is sorted by increasing ID number, with B1950 coordinates, and is arranged in 18 10-degree bands of declination, starting with 80-90, sorted by right ascension within each band. It is used by the program ssao (which calls scat) when the SAO number is known and position, magnitude, and/or spectral type information is desired.

SAOra, the RA-sorted version, is used for fast searches, at least away from the poles, by the program ssao (which calls scat) and for plotting by skymap.

A gzipped 11,586,492-byte file containing both files in Sun/Mac byte order is available here as sao.tar.gz. A gzipped 11,565,967-byte file containing both files in PC/Alpha byte order is available here as saopc.tar.gz. star and scat can read these files on machines with either byte order.

SAO is a 8,287,900-byte file, and SAOra is a 8,287,900-byte file.

Detailed descriptions of the binary header format and binary entry format are available.

An ASCII version with more information for each star is available from NASA's High Energy Astrophysics Science Archive Research Center (HEASARC) at Online documentation is available at

[rsao] [WCSTools ssao]