Note: USNO-A1.0 contains 488,006,860 sources, and was compiled from the blue/red overlaps of the detection lists generated from scans of POSS-I O and E plates (>=-30°) and SRC-J and ESO-R plates (<=-35°). USNO-A1.0 was created by Dave Monet () and collaborators at Flagstaff Station, U.S. Naval Observatory; it is superseded by the new PMM-USNO-A2.0 version. The VizieR search engine uses an on-line compressed version (3.4Gbytes) which was generated at CDS.
Note: The USNO-B Catalog presents positions, proper motions, magnitudes un blue, red and infrared, as well as star/galaxy estimators for 1,045,175,762 objects derived from 3,648,832,040 separate observations. The data were taken from scans of 7,435 Schmidt plates taken from various sky surveys during the last 50 years. USNO-B1.0 catalog was created by Dave Monet and collaborators at http://www.nofs.navy.mil/data/fchpix/ Note that the star/galaxy estimators may be mixed up in dense regions.
Note: The Naval Observatory Merged Astrometric Dataset (NOMAD) contains astrometric and photometric data for over 1 billion stars derived from the Hipparcos (I/239), Tycho-2 (I/259), UCAC2 (I/289), and USNO-B1.0 (I/284) catalogs for astrometry and optical photometry, supplemented by 2MASS (II/246) near-infrared photometry. An efficient remote query program findnomad1 is available in the cdsclient package, for Unix/Linux platforms