SAO catalog
The SAO catalog ( Smithsonian Astrophysical Observatory Star Catalog ) is a star catalog of the Smithsonian Astrophysical Observatory . It was created around 1966 for the astrometric measurement of photo plates and for satellite geodesy . It contains 259,000 stars in the standard epoch 1950.0 down to an apparent magnitude of 9 m .
The catalog was compiled from the best sources available at the time (AGK1 and AGK2 catalogs, FK4 , General Catalog GC, Cape Zone and some other star catalogs ) and has an accuracy of around 0.5 "in the northern sky, and slightly worse in the south.
The four-volume work is supplemented by a set of 152 star maps that show the entire sky overlapping in 20 × 20 ° parts. They are precisely plotted on the scale by special satellite cameras .
In the latest edition, the epoch of the position data is J2000.0 . The SAO catalog has contained the star numbers in the HD and BD catalog as well as the movements of all stars since the first edition . Therefore it can be used for many other purposes besides astrometry and geodesy , e.g. a. for stellar statistics back to the 19th century .
The names in the SAO star catalog begin with the letters SAO followed by a number. The numbers are assigned in eighteen 10 ° bands, with the stars within a band arranged according to right ascension .