GCX provides a complete set of data-reduction functions for CCD photometry, with frame WCS fitting, automatic target identification, aperture photometry of target and standard stars, single-frame ensemble photometry data reduction, multi-frame color coefficient fitting, extinction coefficient fitting, and all-sky photometry. It also controls CCD cameras and telescopes, and implements automatic observation scripting. Cameras are controlled through a hardware-specific server, to which gcx connects through a TCP socket. The program can control telescopes which use the LX200 protocol, and refine pointing by matching images to the GSC catalog position of stars. It generates FITS files with comprehensive header information.
