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Proceedings Paper

MOSFIRE: a multi-object near-infrared spectrograph and imager for the Keck Observatory
Author(s): Ian S. McLean; Charles C. Steidel; Keith Matthews; Harland Epps; Sean M. Adkins
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Paper Abstract

MOSFIRE, the multi-object spectrometer for infra-red exploration, is a near-IR (0.97-2.45 micron) spectrograph and imager for the Cassegrain focus of the Keck I telescope. The optical design provides imaging and multi-object spectroscopy over a field of view (FOV) of 6.14' x 6.14' with a resolving power of R~3,270 for a slit width of 0.7 arc seconds (2.9 pixels along dispersion). The detector is a 2.5 micron cut-off 2K x 2K H2-RG HgCdTe array with a SIDECAR ASIC for detector control. A special feature of MOSFIRE is that its multiplex advantage of up to 46 slits is achieved using a cryogenic Configurable Slit Unit (developed in collaboration with the Swiss Centre for Electronics and Micro Technology) reconfigurable under remote control in <5 minutes without thermal cycling. Slits are formed by moving opposable bars from both sides of the focal plane. An individual slit has a length of ~7.1 arc seconds but bar positions can be aligned to make longer slits. A single diffraction grating in two positions along with order-sorting filters gives essentially full coverage of the K, H, J and Y bands using 3rd, 4th, 5th or 6th order respectively. The grating and a mirror are mounted back-to-back, and when the bars are retracted from the FOV MOSFIRE becomes a wide-field imager. A piezo tip-tilt mirror following the field lens is used to provide flexure compensation at the 0.1 pixel level. Two large CCR heads allow the instrument to reach operating temperature in ~7 days. MOSFIRE is currently in construction.

Paper Details

Date Published: 23 July 2008
PDF: 12 pages
Proc. SPIE 7014, Ground-based and Airborne Instrumentation for Astronomy II, 70142Z (23 July 2008); doi: 10.1117/12.788142
Show Author Affiliations
Ian S. McLean, Univ. of California, Los Angeles (United States)
Charles C. Steidel, Caltech Optical Observatories, California Institute of Technology (United States)
Keith Matthews, Caltech Optical Observatories, California Institute of Technology (United States)
Harland Epps, UCO/Lick Observatory, Univ. of California, Santa Cruz (United States)
Sean M. Adkins, W. M. Keck Observatory (United States)

Published in SPIE Proceedings Vol. 7014:
Ground-based and Airborne Instrumentation for Astronomy II
Ian S. McLean; Mark M. Casali, Editor(s)

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