This SAOimage display shows the alignment of HST Guide Stars with a test image with a world coordinate system. immatch can be run to list matches between HST Guide Stars and sources found in the image. The command used was
saogsc test.ftswhere saogsc is
saoimage -reg `imgsc -q o -r 10 $1` -wcscom sgsc_-ha_%s $*Clicking the w key on the star closest to the center returns the following:
sgsc 2.5, 8 December 1998, Doug Mink SAO Find closest star GSC number RAJ2000 DecJ2000 Mag Type Arcsec 4383.0340 09:55:23.638 +69:00:49.57 14.59 0 1.56