GTC OSIRIS Optical Imager and Spectrograph
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The Optical System for Imaging and low-Intermediate Resolution Integrated Spectroscopy (OSIRIS) of the Gran Telescopio Canarias (GTC) is an imager and spectrograph for optical wavelengths. Wavelength range coverage is 0.365 - 1.05 microns; total field of view is 7.8 x 8.5 arcminutes for direct imaging and 7.5x6.0 arcminutes for multi-object spectroscopy.

OSIRIS has a number of operating modes. Imaging modes include: broad, medium, and narrow band imaging with various filters; fast photometry; and frame transfer photometry.  Spectroscopic modes include long-slit spectroscopy and multi-object spectroscopy.