The multi-object double spectrographs for the Large Binocular Telescope

Richard W. Pogge, Bruce Atwood, David F. Brewer, Paul L. Byard, Mark Derwent, R. Gonzàlez, Paul Martini, Jerry A. Mason, Thomas P. O'Brien, Patrick S. Osmer,

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010 · 151 citations · 0 references

Concepts

Abstract

The Multi-Object Double Spectrographs (MODS) are two identical high-throughput optical low- to medium-resolution CCD spectrometers being deployed at the Large Binocular Telescope (LBT). Operating in the 340-1000nm range, they use a large dichroic to split light into separately-optimized red and blue channels that feature reflective collimators and decentered Maksutov-Schmidt cameras with monolithic 8×3K CCD detectors. A parallel infrared laser closed-loop image motion compensation system nulls spectrograph flexure giving it high calibration stability. The two MODS instruments may be operated together with digital data combination as a single instrument giving the LBT an effective aperture of 11.8-meter, or separately configured to flexibly use the twin 8.4-meter apertures. This paper describes the properties and performance of the completed MODS1 instrument. MODS1 was delivered to LBT in May 2010 and is being prepared for first-light in September 2010.