imua2 is a link to the
utility which finds all of the
U.S. Naval Observatory A-2.0 Catalog
objects in a FITS or IRAF image and lists their sky
and image positions. World coordinate system (WCS) information must be
present in the image header to describe, in a standard way, the relationship
between sky coordinates and image pixels.
This information is used by the program to find the region in the sky to
search and to transform right ascension and declination sky coordinate pairs
to image coordinate (X,Y) pairs. Output is sent to a file called
filename.uac and to standard output if the -v flag is set.
The UA2 number is the zone ((90 + declination in degrees) * 10) followed by
the sequence number of the star within the RA-sorted zone. This number
will change with each release of the USNO A catalog.
Find USNO-A2.0 Stars in Image Region
Set the environment variable UA2_PATH to the directory containing
the region files or UA2_ROOT to the directory below which the CDROMs
(ua001, ua002,...ua011) are mounted. If neither environment variable is set,
the default is to look at /data/ua.
The minimum command line is
imua2 FITS or IRAF filename
The same effect can be obtained by running
imcat -c ua2 FITS or IRAF filename
- List the 10 brightest USNO-A2.0 Catalog stars in a FITS image from a CDROM
- List the USNO-A2.0 Catalog stars in a FITS image to a file
- Plot USNO-A2.0 Catalog stars onto a FITS image