immatch is a utility for matching stars in a FITS or IRAF image with
a world coordinate system (WCS) in its header
with stars in a reference catalog. The WCS is the relationship between sky
coordinates and image pixels and can be described in a standard way in the
header of an image. If there is no WCS in the header,
imwcs may be used to set one.
Match Image Stars with Catalog Stars
The HST Guide Star Catalog, the USNO UJ Catalog, the USNO A Catalogs, or
a user-supplied catalog may be used.
There are two USNO-B1.0-specific parameters which can be set on the command
||If the object is found on fewer than this many plates, where the range
is 2-5, it is left off the list. All Tycho-2 stars, where the catalog value
of this number is set to zero, are included unless number is negated.
The default value set in the file libwcs/ubcread.c is 0.
For the most accurate positions, use minid=4.
||If the proper motion quality flag is less than this number, proper
motion is never added to the catalog position. The range is 1-9 from
the catalog, or 10 if the proper motion is from the Tycho-2 Catalog.
Setting this to 11 will never add proper motion.
The default value set in the file libwcs/ubcread.c is 3.
For the best proper motions, use minpmqual=9.
1. Find HST Guide Star Catalog Stars in an image
2. Find USNO-A2.0 catalog stars using SExtractor to find stars in an image