... DEIMOS (the DEep Imaging Multi-Object Spectrograph) began producing scientific data from the Keck II telescope in 2002 June. ... Filters and gratings may be swapped, gratings and mirrors tilt, readout modes and active amplifiers of the 8-CCD mosaic change, and numerous field-specific astrometric slitmasks may be inserted. ... The FITS files are compatible with existing local conventions for mosaic image display systems and also with incipient FITS WCS standards. ... 2002). ... CCD . ...