First Light Instrumentation

The choice for SALT's first generation instruments was based on the science drivers and technical capabilities of the SALT partners. The partners benefit from the science capabilities of the instruments and are taking the lead in their construction. Identifying key niche areas of research, where SALT can be competitive with similar sized, but larger budget, telescopes is important. Since SALT plans to be primarily a spectroscopic facility, the roles of the various instruments may be assessed in terms of the most efficient methods of sampling in both wavelength and space. The assignment of roles to the spectroscopic instruments requires consideration, not only of wavelength range and spectral resolution, but also how one multiplexes both spectral and spatial information (i.e. 3-D datacubes) onto 2-D detectors with limited pixels. For SALT there is significant emphasis on the prime focus instrumentation, which will specialize in making use of access to the spatial dimension (i.e. the science field of view of 8 arcminutes in diameter).

SALT will utilize fibre-fed spectroscopy as an important observational tool, although the SALT prime focus spectrometer will target most of the multi-object and medium resolution (R up to ~10,000) roles. Many of SALT's science drivers call for good blue/UV performance, down to the atmospheric UV cutoff of ~320 nm, as well as imaging spectroscopy (with Fabry-Perot etalons) and polarimetric capability. These are best conducted, in terms of efficiency and throughput, at the prime focus. In addition, high dispersion spectroscopy, capable of excellent radial velocity precision, will be provided with a fibre-fed echelle spectrograph, housed in an environmentally controlled spectrometer room.

Following the deliberations of the SALT Science Working Group (SSWG), the following have been chosen as the first-light instruments for SALT:

Robert Stobie Spectrograph (RSS) (originally called PFIS; Prime Focus Imaging Spectrograph)
Fibre-fed High Resolution Spectrograph (HRS)

Optical imaging and acquisition camera (SALTICAM)