Faint-Object Spectrograph For Space Telescope

The Faint Object Spectrograph (FOS) is being designed and built for use with Space Telescope to provide digitized spectra of faint astronomical objects over the wavelength range from 115 to 700nm at resolving powers of 1000 and 100. A variety of concave gratings and prisms is employed to form nearly stigmatic spectra on either of two Digicon photon counting detectors which are optimized for two different but overlapping spectral ranges. The science goals are summarized, and the optical and detector designs and their predicted performance are discussed.