Image World Coordinate Setting Program

imwgsc2 is an alias for imwcs, a program which sets the world coordinate system (WCS) of a FITS or IRAF image. 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. The program was originally written at the University of Iowa, but has been adapted and amplified by Doug Mink at the Smithsonian Astrophysical Observatory.

imwgsc2 uses the GSC II Catalog, an total update of the Hubble Space Telescope Guide Star Catalog containing 60 times as many stars, 998,402,801. The USNO-B1.0 catalog (imwub1) has few more stars (1,036,366,767), but its proper motions are not quite as good. The 2MASS Point Source Catalog (imwtmc) is another recent epoch catalog, and is based on IR images.

A set of image stars may be hand-matched to sky positions and used to get a WCS or set initial values for a reference catalog-based WCS (See example).

Command Line Arguments


Using SExtractor to find stars in an image

Find image WCS using HST Guide Stars as references

Find image WCS using pre-matched stars and USNO-A2.0 Stars

Last updated 19 October 2001 by Doug Mink

Telescope Data Center [WCSTools Programs]