title: USNO CCD Astrograph Catalog
text: # USNO CCD Astrograph Catalog
  
  The USNO CCD Astrograph Catalog (UCAC) is an astrometric star catalog of the United States Naval Observatory.
  
  ## 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.
  
  