Advanced cooled grating spectrometer for the UKIRT

The main features of the Cooled Grating Spectrometer (CGS4), for the United Kingdom Infrared Telescope (UKIRT), are described. The CGS4 for use at 1 to 5 microns is designed to fully utilize foreseeable arrays and to take maximum advantage of the solid imaging detectors. The spectrometer can use low dispersion first order grating in a back-to-back configuration with a high dispersion echelle, giving wavelength resolutions from approximately 1,000 to 24,000.