The USNO CCD Astrograph Catalog (UCAC) is an astrometric

star catalog A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, ...

of the

United States Naval Observatory United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...

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.UCAC5: New Proper Motions using Gaia DR1
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References

External links

UCAC home page
Astronomical catalogues of stars {{astronomical-catalogue-stub