imgsc is a link to the
utility which finds all of the
Hubble Space Telescope Guide Star 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.gsc and to standard output if the -v flag is set.
The minimum command line is
Find HST GSC Stars in Image Region
imgsc FITS or IRAF filename
The same effect can be obtained by running
imcat -c gsc FITS or IRAF filename
- List the 10 brightest HST Guide Stars in an image
- List the HST Guide Stars in an image into a file
- Plot HST Guide Stars over an image using SAOimage