|
The U.S. Naval Observatory is
one of the oldest scientific
agencies in the country. Established in 1830 as the Depot of Charts
and Instruments, its primary mission was to care for the U.S. Navy's
chronometers, charts, and other navigational equipment. Today, USNO is
the preeminent authority in the areas of
Precise Time and Astrometry,
and distributes Earth
Orientation parameters and other Astronomical Data
required for accurate navigation and fundamental astronomy. USNO
headquarters in Washington, DC is the administrative and scientific hub
of Observatory
operations and is home to the
James M. Gilliss Library, one
of the most complete collections of astronomical literature in the
world. USNO operates a remote
observing station at
Flagstaff, AZ and an
Alternate Master Clock
Facility at Schriever AFB, CO.
|
|
|
The USNO CCD Astrograph
Catalog is an astrometric observational program which started
in February 1998 at CTIO. All sky observations were completed in May 2004.
The final catalog is expected to be released by early 2009. The second data release (UCAC2)
became public in 2003. Positions accurate to 20 mas for stars in the 10 to 14
magnitude range are obtained. At the limiting magnitude of R=16 the catalog
positions have a standard error of 70 mas. Proper motions are provided using
various earlier epoch data. Photometry is poor, with errors on the order 0.1
to 0.3 magnitudes in a single, non-standard color.
|
|
