Astrographic Catalogue

The Astrographic Catalogue is part of the international Carte du Ciel program designed to photograph and measure the positions of all stars brighter than magnitude 11.0. (The brightest stars of all are missing due to their images being grossly over-exposed and, therefore, not being measured). In total, over 4.6 million stars were observed, many as faint as 13th magnitude. This project was started in the late 1800s, and most observations were made between 1895 and 1920. Data from the Astrographic Catalogue was recently used by the US Naval Observatory in producing the ACT Catalog.