USNO-A2.0

A catalog of 526,280,881 stars, based on a re-reduction of the Precision Measuring Machine (PMM) scans that were the basis for the USNO-A1.0 catalog. A2.0 uses the ICRF as realized by the USNO ACT catalog, and presents right ascension and declination (J2000, epoch of the mean of the blue and red plate) and the blue and red magnitude for each star.