ASCfit - Automatic Stellar Coordinate Fitting Package

A modular software package for automatically fitting astrometric world coordinates (WCS) onto raw optical or infrared FITS images is presented. Image stars are identified with stars in a reference catalog (USNO-A2 or 2MASS), and coordinates derived as a simple linear transformation from (X,Y) pixels to (RA,DEC) -- to the accuracy level of the reference catalog used. The package works with both optical and infrared images, at sidereal and non-sidereal tracking rates.