Performance of MARS during the 8-11 September 2001 T&E run:

The layout of MARS can be found here.

CCD: (LBNL 1980x800)

        Format       : 1980 x 800
        Gain         : 2.0 e-/adu
        Read Noise   : 8.0 e-
        Dark Current : 10-25 electrons/hour
        Pixel size   : 15 microns
        Pixel scale  : 0.8618"/pix (determined from 700 stars in M15 imaged through an I-band filter)
                (quadratic term in solution)
 

With VPH grism VG8050-450

        Dispersion   : 2.91 Angstroms/pixel
        Coverage (in long slit mode) : 5310 A - 1.1 micron
        Note: The VG8050-450 grism includes a OG550 filter used
              as a cover plate. No additional order-sorting filter
              is necessary with this grism.
        Grism efficiency:
        # Lambda (A)  Efficiency
             5500       0.1695
             6000       0.5096
             6500       0.6940
             7000       0.7992
             7500       0.8473
             8000       0.8545
             8500       0.8199
             9000       0.7858
             9500       0.7291
           10000       0.6726
           10500       0.5555

Total system throughput:

  (Mayall + MARS + VG8050-450 + detector) 2001september
  Atmosphere and slit losses are not included.
          5300.0    0.000
          5500.0    0.037
          6000.0    0.166
          6500.0    0.282
          7000.0    0.360
          7500.0    0.395
          8000.0    0.391
          8500.0    0.358
          9000.0    0.304
          9500.0    0.228
        10000.0    0.110
        10500.0    0.000

  Other grisms are available, but have not been tested for
  throughput. GR730 and GR780-1 have lower throughputs than
  VG8050-450. See
        http://www.noao.edu/kpno/manuals/l2mspect/node9.html
 for additional information on other grisms.

The total system throughput was derived using observations of various spectrophotometric standards on different nights obtained through a wide (13.5 arcsec) diameter aperture.

Modes of Operation:

        Imaging
                Imaging can be done by removing the grism and the
                slitmask. The decker must be *IN* for imaging.
                FOV = 5.2 arcmin diameter circle
        Long slit
                Long slit spectroscopy can currently be done only
                using the long slit slit masks. Long slits of various
                widths are available: (1.0",1.4",1.8",2.5",3.2",3.7",etc.)
                Several setup masks and wide-slit apertures are also
                available.

        Slit mask
                see
        http://www.noao.edu/kpno/manuals/multisl/multisl.html
                for information on designing and observing with multislits.

                We are in the process of creating a more user-friendly
                system of designing masks for MARS. Stay tuned!
 

        Nod and Shuffle:
                The nod-and-shuffle mode may be used with either the long slit
                or multi-slit modes. The field of view
                or slitlet density must be modified in order to permit the
                storage space for nod and shuffle. In the case of long slit
                observations or observations using the highest slit density,
                the FOV is reduced to a maximum of 228" = 3.8'. The true
                slit length may be even less than this, since it depends on
                how precisely the CCD is centered in the beam. If slitmasks
                are being used and the slit density is not the driving factor,
                the full FOV (5.2') may be used but gaps = 2 x slit length
                between slitlets.

                We are in the process of creating a more user-friendly
                system of designing masks for MARS. Stay tuned!