Find USNO-A2.0 Stars in Image Region

WCSTools programs
imua2 is a link to the WCSTools imcat 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.

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

Command Line Arguments


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

Last updated 30 July 2002 by Doug Mink dmink@cfa.harvard.edu

Telescope Data Center