The NIR upgrade to the SALT Robert Stobie Spectrograph

Type Conference Paper
Names Andrew I. Sheinis, Marsha J. Wolf, Matthew A. Bershady, David A. H. Buckley, Kenneth H. Nordsieck, Ted B. Williams
Conference Name Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series
Volume 6269
Pages 153
Date July 1, 2006
URL http://adsabs.harvard.edu/abs/2006SPIE.6269E.153S
Library Catalog NASA ADS
Abstract The near infrared (NIR) upgrade to the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT), RSS/NIR, extends the spectral coverage of all modes of the visible arm. The RSS/NIR is a low to medium resolution spectrograph with broadband imaging, spectropolarimetric, and Fabry-Perot imaging capabilities. The visible and NIR arms can be used simultaneously to extend spectral coverage from approximately 3200 Å to 1.6 μm. Both arms utilize high efficiency volume phase holographic gratings via articulating gratings and cameras. The NIR camera is designed around a 2048x2048 HAWAII-2RG detector housed in a cryogenic dewar. The Epps optical design of the camera consists of 6 spherical elements, providing sub-pixel rms image sizes of 7.5 +/- 1.0 μm over all wavelengths and field angles. The exact long wavelength cutoff is yet to be determined in a detailed thermal analysis and will depend on the semi-warm instrument cooling scheme. Initial estimates place instrument limiting magnitudes at J = 23.4 and H(1.4-1.6 μm) = 21.6 for S/N = 3 in a 1 hour exposure well below the sky noise.
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