The Space Telescope Imaging Spectrograph design

The Space Telescope Imaging Spectrograph (STIS) instrument was installed on the Hubble Space Telescope (HST) during the second servicing mission, in 1997 February. Four bands cover the wavelength range of 115-1000 nm, with spectral resolving powers between 26 and 200,000. Camera modes are used for target acquisition and deep imaging. Correction for HST's spherical aberration and astigmatism is included. The 115-170 nm range is covered by a CsI MAMA (Multianode Microchannel Array) detector and the 165-310 nm range by a Cs,Te MAMA, each with a format of 2048 x 2048 pixels, while the 305-555 and 550-1000 nm ranges are covered by a single CCD with a format of 1024 x 1024 pixels. The multiplexing advantage of using these two-dimensional detectors compared with the 1 x 512 pixel detectors of the first-generation spectrographs is 1 or 2 orders of magnitude, depending on the mode used. The relationship between the scientific goals and the instrument specifications and design is discussed.