UCAC (USNO CCD Astrograph Catalog)

The USNO CCD Astrograph Catalog (UCAC) is a star catalog created by the United States Naval Observatory using a special telescope with a digital camera. It provides precise positions and brightness measurements for millions of stars, primarily in the southern sky. Launched in the early 2000s, UCAC serves astronomers and researchers by enabling them to study the motions and properties of stars, support navigation, and improve our understanding of the universe. The data from UCAC is essential for various fields in astronomy, including star mapping and celestial navigation.