Note: The Guide Star Catalog has been constructed to support the operational need of the Hubble Space Telescope. It contains over 25 million positions for about 19 million objects, of which more than 15 million are classified as stars. The version 1.2 is a new astrometric reduction which results in absolute position errors about 0.3-0.4 arcsec. (see GSC pages at URL http://www-gsss.stsci.edu/gsc/gsc.html)

I/254/out Post annotation

The HST Guide Star Catalog, Version 1.2 (Lasker+ 1996) ReadMe+ftp 2001AJ....121.1752M metaI/254/out The Full Catalogue (25241730 positions) (25241730 rows)

Note: The GSC-ACT (or GSC1.3) is a recalibration of the GSC1.1, the catalogue constructed to support the operational need of the Hubble Space Telescope, with the ACT, the combination of the Astrographic Catalogue and the Tycho catalogue derived from the Hipparcos mission; see http://www.projectpluto.com/gsc_act.htm for more details about this recalibration.

I/255/out Post annotation

The HST Guide Star Catalog, Version GSC-ACT (Lasker+ 1996-99) ReadMe+ftp metaI/255/out The GSC-ACT Full Catalogue (25241730 positions) (25241730 rows)

Note: The construction of the GSC-II is still in progress: this version has no proper motions, and the magnitude limits are 18.5 in F (red) and 19.5 in J (blue). The data are copyrighted, check the data use Policy.

I/271/out Post annotation

The GSC 2.2 Catalogue (STScI, 2001) ReadMe+ftp metaI/271/out The Full GSC2.2.1 Catalogue (455851237 objects) (455851237 rows)

Note: This version of the GSC-II has no proper motions, but the limits on brightness which existed on GSC2.2 (F<18.5, B_j<19.5) were removed.

I/305/out Post annotation

The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006) ReadMe+ftp 2008AJ....136..735L metaI/305/out The Full GSC2.3.2 Catalogue (945592683 objects) (945592683 rows)

Note: The Guide Star Catalog has been constructed to support the operational need of the Hubble Space Telescope; it is primarily based on an all-sky, single epoch, single passband collection of Schmidt plates. It contains over 25 million positions for about 19 million objects, of which more than 15 million are classified as stars.

I/220/out Post annotation

The HST Guide Star Catalog, Version 1.1 (Lasker+ 1992) ReadMe+ftp metaI/220/out The Full Catalogue (25258765 positions) (25258765 rows)