UVSTAR - AN IMAGING SPECTROGRAPH WITH TELESCOPE FOR THE SHUTTLE HITCHHIKER-M PLATFORM

UVSTAR (Ultraviolet Spectrograph Telescope for Astronomical Research) is an EUV spectral imager intended as a facility instrument devoted to solar system and stellar astronomy. It covers the wavelength range of 500 to 1250 angstrom, with sufficient spectral resolution to separate atomic emission lines and to form spectrally resolved images of exten ded plasma sources. Targets include the lo plasma torus at Jupiter, ho t stars, and planetary nebulae. UVSTAR will make useful measurements o f emissions from Earth's atmosphere as well. UVSTAR consists of a pair of telescopes and concave-grating spectrographs that cover the overla pping spectral ranges of 500 to 900 and 850 to 1250 angstrom. The tele scopes use two 30-cm-diam off-axis paraboloids having a focal length o f 1.4 m. An image of the target is formed at the entrance slits of two concave grating spectrographs. The gratings provide dispersion and re image the slits at the detectors, intensified CCDs. The readout format of the detectors can be chosen by computer, and three slit widths are selectable to adapt the instrument to specific tasks. The spectrograp h package has internal gimbals, which allow rotation of +/- 3 deg abou t each of two axes. Dedicated finding and tracking telescopes will acq uire and track the target after rough pointing is achieved by orientin g the Orbiter. Responsibilities for the implementation and utilization of UVSTAR are shared by groups in Italy and the United States. UVSTAR is scheduled for flight in early 1995, timed for an opportunity to ob serve the Jovian system.