Many of the stars have SAO designations from the Smithsonian Astrophysical Observatory Star Catalog; others are identified by ZC (Zodiacal Catalogue), TYC (Tycho-2), PPM (Positions and Proper Motions), or TAC (Twin
Astrographic Catalog) numbers.
Many of the stars are in the SAO Star Catalog; others are identified by their numbers in the
Astrographic Catalog -- Tycho (ACT), Tycho Reference Catalog (TRC), Positions and Proper Motions (PPM), Twin
Astrographic Catalog (TAC), or Hubble Guide Star Catalog (GSC).
This catalog is known as the
Astrographic Catalog Reference Stars, or ACRS.