The USNO CCD Astrograph Catalog (UCAC) is an astrometric star catalog of the United States Naval Observatory.
| Edition | Description | |
|---|---|---|
| UCAC-1 | The first preliminary edition, published in March 2000, gives the positions and proper motions of over 27 million stars in the southern hemisphere in the brightness range 8–16. | |
| UCAC-2 | The second issue was the IAU published General Assembly in Sydney (2003) and includes positions and proper motions of about 50 million stars. | |
| UCAC-3 | The third edition was published in the IAU General Assembly in Rio (August 2009). | |
| UCAC-4 | The fourth edition was published in August 2012. Since Spring 2015, the successor URAT is available. | |
| UCAC-5 | The fifth edition was published in February 2017.[1] [2] |