Note: USNO-A2.0 contains 526,280,881 sources, and is based on a re-reduction of the Precision Measuring Machine (PMM) scans from POSS-I O and E plates (>=-18°) and SRC-J and ESO-R plates (<=-20°). USNO-A2.0 was created by Dave Monet () and collaborators at Flagstaff Station, U.S. Naval Observatory. The major difference between USNO-A2.0 and its previous version USNO-A1.0 is that A1.0 used the Guide Star Catalog as its reference frame whereas A2.0 uses the ICRF as realized by the USNO ACT catalog (Urban et al. 1997). The VizieR search engine uses an on-line compressed version (3.6Gbytes) which was generated at CDS.
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.
Note: Zone -30/+50deg
Note: This version of the GSC-II has no proper motions, but the limits on brightness which existed on GSC2.2 (F<18.5, Bj<19.5) were removed.
Note:
Note: Zone -40/+50deg
(original column names in green) (1692919135 rows)
(original column names in green) (1811709771 rows)
Note: SDSS is also available from http://www.sdss.org/
Note: Details of surveyed literature