The U.S. Naval Observatory SA2.0 is a catalog of 55,368,239 sources intended
to provide a grid of astrometric reference objects over the whole sky.
It is a spatially sub-sampled version of
and provides an astrometric reference catalog for asteroid hunters and
other folks who do not need all of that 11-CDROM, 526,280,881-source catalog.
The format is the same as USNO-A2.0.
USNO-SA 2.0 Astrometric Reference Catalog
This catalog is available via anonymous ftp from
For susa2, you need only the
files ending in .cat.
This catalog used to be distributed on a single CD-ROM obtained by a request
http://ad.usno.navy.mil/usnosa.html, which now reads,
"This catalog is no longer available for distribution."
Catalog access software in C for
Unix systems has been written by
Doug Mink at the
Harvard-Smithsonian Center for Astrophysics.
[WCSTools UAC Programs]
[A2.0 from USNO]