The Fifth U.S. Naval Observatory CCD Astrograph Catalog

The US Naval Observatory (USNO) has a long history of providing accurate astrometric data for millions of stars from their own observations plus other data. The USNO CCD...美国海军天文台（United States Naval Observatory, USNO）有着悠久的历史，可基于自身观测数据及其他外源数据，为数百万颗恒星提供高精度的天体测量数据。该天文台的电荷耦合器件（Charge-Coupled Device, CCD）...