Astrographic Catalog

The Astrographic Catalog was to be the product of an effort begun in 1887 to photograph the entire sky down to magnitude 11.5. As conceived, it would provide a reference of brighter stars for a simultaneous analogous project, the Cart du Ciel, which would cover the sky to magnitude 14. The Astrographic Catalog effort was carried on for decades, the sky divided into more than twenty zones, assigned to individual observatories around the world. Eventually, as efforts dwindled over time, the USNO took up the project of completing it, which evolved into more modern efforts. The plates produced by the earlier observatory efforts have been of use for comparison with recent efforts such as Hipparcos, in the study of proper motion