Find USNO-SA1.0 Stars in Image Region

imusa1 is a link to the WCSTools imcat utility which finds all of the U.S. Naval Observatory SA-1.0 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.usa1 and to standard output if the -v flag is set. The UAC 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 UA catalog.

Set the environment variable USA1_PATH to the directory containing the CDROM. If the environment variable is not set, the default is to look at /data/usnosa10.

The minimum command line is

imusa1 FITS or IRAF filename
The same effect can be obtained by running
imcat -c usa1 FITS or IRAF filename

Command Line Arguments


List the 10 brightest USNO-SA1.0 Catalog stars in a FITS image
List the USNO-SA1.0 Catalog stars in a FITS image to a file
Plot USNO SA-1.0 Catalog stars onto a FITS image

Last updated 11 December 1998 by Doug Mink

Telescope Data Center [WCSTools programs] [imcat] [USNO catalog access programs]