The infrared space observatory camera

At the focal plane of the ISO 60 cm telescope, ISOCAM will take images of the sky in the wavelength range 2.5 to 17 μm. It features two independent channels, containing each a 32×32 array detector. The long wavelength (4 17 μm) detector, developed by LIR-LETI specifically for ISOCAM, is a Si:Ga array bonded with indium bumps to a DV readout circuit. The short wavelength (2.5 5.5 μm) detector, developed by SAT, is an InSb array with a CID readout. Only one channel operates at a time. The channel selection is obtained with two field mirrors supported by a wheel. The field mirror in operation is in the focal plane of the telescope, covering the 3 arcmin field of view, and reflecting the light into one or into the other channel. In each channel, 10 or 12 discrete band pass filters and CVFs with resolution 45 are mounted on a wheel. A second wheel supports a set of lenses, which reimage the focal plane of the telescope on the array, with a pixel field of view of 1.5, 3, 6 or 12 arcsec. Two integrating spheres, illuminated through small holes by black body sources, are mounted on the selection wheel, for flat fielding and calibration purposes. The flight model of ISOCAM, fully tested and calibrated, has been, delivered to ESA and is ready to be integrated in the satellite, whose expected launch date is September 1995.