The Smithsonian Astrophysical Observatory Star Catalog is an astrometricstar catalogue. It was published by the Smithsonian Astrophysical Observatory in 1966 and contains 258,997 stars. The catalogue was compiled from various previous astrometric catalogues, and contains only stars to about ninth magnitude for which accurate proper motions were known. Names in the SAO catalogue start with the letters SAO, followed by a number. The numbers are assigned following 18 ten-degree bands of declination, with stars sorted by right ascension within each band.
^Star Catalog: Positions and Proper Motions of 258,997 Stars for the Epoch and Equinox of 1950.0, Smithsonian Astrophysical Observatory Staff, Publications of the Smithsonian Institution of Washington, D.C., no. 4652, 4 vols., 1966 (reprinted 1971.)