WCSTools: Image World Coordinate System Utilities

The WCSTools are portable C utility programs and subroutines for setting and using the world coordinate system (WCS) of a FITS or IRAF image. The WCS describes the relationship between sky coordinates, such as right ascension and declination, and image pixels, and can be described using standard keywords in an image header. The subroutine library is currently used by the image display and browsing programs SAOimage, SAOtng, and Skycat to translate between image pixels and sky coordinates. Some subroutines have been improved and new ones have been added to read and write all legal FITS image data types and to deal with IRAF .imh (OIF) files as easily as FITS files. The programs in this package set the WCS of an image, convert between pixel and sky coordinates in an image, and find catalog stars in the region of the sky which the image covers.