USNO-A V2.0, A Catalog of Astrometric Standards

USNO-A2.0 is a catalog of 526,280,881 stars, and is based on a re-reduction of the Precision Measuring Machine (PMM) scans that were the basis for the USNO-A1.0 catalog....USNO-A2.0星表收录了526,280,881颗恒星，其数据基于对精密测量机（Precision Measuring Machine, PMM）扫描结果的重新归算，而该扫描数据正是USNO-A1.0星表的构建基础……