Smithsonian Astrophysical Observatory Star Catalog contain the 258,996 stars.

The Smithsonian Astrophysical Observatory star catalogue was compiled from various previous astrometric catalogues, and contains only the stars to about ninth magnitude for which accurate proper motions were known. The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory (HCO) to form the Harvard-Smithsonian Center for Astrophysics (CfA). ... In astronomy, many stars are referred to simply by catalogue numbers. ... This article does not cite its references or sources. ...

Names in the SAO catalogue start with the letters SAO, followed by a number. The numbers are assigned following 18 ten-degree bands in the sky, with stars sorted by right ascension within each band. Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ...

Examples from SAO catalogue

SAO 67174 is Vega
SAO 113271 is Betelgeuse
SAO 40012 is HD 277559
Vega (also known as Alpha Lyrae or 3 Lyrae) is a star approximately 25. ... Hubble UV picture of Betelgeuse. ...

External links

• Official SAO Star Catalog webpage