INSTRUMENT OVERVIEW

The 4-Meter R.C. Spectrograph with UV Fast Camera and CCD in a Universal dewar offers an excellent combination for low to moderate resolution (270<=R<=6000) two-dimensional spectroscopy of astronomical sources. The Tektronix 2048x2048 chip T2KB, offers good sensitivity from near the atmospheric cutoff to the 9500A region. A CCD quantum efficiency of ~60% occurs in the region 4000-8000A. The Tek chips have 24 micron square pixels and can cover the full slit length (5.2 arc-minutes) with a scale of ~0.69 arcsecs/pixel. Spectral resolutions of 1-15A are available using a large selection of diffraction gratings. The CCD system operates under IRAF/ICE on a Sun Sparc 10 workstation.

With the T2KB chip, the system can obtain spectra of 18th. magnitude (V) stellar objects in an hour at R~430 (14A) with a S/N~60 per pixel. The overall efficiency of the system, including the throughput of the atmosphere, telescope and spectrograph/detector, is 6-8% in the 5000-6000A region. The Tek CCDs typically have rms read noise of 3-5 electrons and a full-well capacity of ~200,000 electrons for linearity <=0.05%. The cosmic ray event rate is significant and it is suggested that long exposures be broken up into 30-60 minute segments to discriminate against these events.

Two operating modes are available: the normal long slit mode and a multi-slit configuration using special entrance masks. Potential users of the multi-slit mode should refer to to the manual MULTI-SLITS AT KITT PEAK which is available via Mosaic or FTP. Multi-slits require considerably more advanced preparation than is required for the conventional long slit mode. Potential users are urged to talk with one of the staff contacts [J.DeVeny] early.

Full data reduction capability using IRAF is available at the 4-meter using either of two SUN-Sparc workstations (UNIX).


deveny@noao.edu
Friday, August 4, 1995