CFHT, Instruments, Detectors, CCDs, STIS2


  • STIS 2 is a SITe device from the HST STIS project. It is available for use on MOS/SIS and AOB only.
  • Current status: Device is in active service.
  • Quantum efficiency: Curve.
  • Characteristics and performance: since fall 1996, STIS2 operates in a faster mode as described in this memorandum. Other characteristics (! some are no longer valid) can be found in the April 1996 memorandum.
  • Pixels: 2048 x 2048. 20 prescan. Because there are output amplifiers on both ends of the serial register and each of these has 20 prescan pixels, the full image will incorporate 20 bias-level pixels on each side of the image which are derived from these prescan pixels. At CFHT, when reading the CCD from a single amplifier (the normal condition), we reject the first 20 pixels from the image and read 40 pixels beyond the far end of the image. Thus pixels 2049 to 2068 of each row of the final image are overscan which are derived from the physically present prescan pixels in the serial register which would feed the other output amplifier if it were used. Pixels 2069 to 2088 of each row of the final image are overscan which are derived from clocking nonexistent pixels. The latter pixels are overscan as defined by most normal CCD systems. Either or both sets of overscan may be used to establish the bias level for the given image.
  • Pixel size: 21 micron square. (This is larger than the standard 15 microns, but any disadvantage over Loral 3, for example, is more than made up by the improved QE response.)
  • Readout noise: ~9 electrons/pixel.
  • Readout time: ~2 min


  • On MOS
  • On Musicos
  • Dewar Drawings: