  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 A to 1.6 um.
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 um 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 um) = 21.6 for
S/N = 3 in a 1 hour exposure well below the sky noise.
