Presentation
9 July 2018 WFOS instrument trade study: slicer vs. fiber instrument concept designs and results (Conference Presentation)
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Abstract
The Wide Field Optical Spectrometer (WFOS) is a seeing limited, multi-object spectrograph and first light instrument for the Thirty Meter Telescope (TMT) scheduled for first observations in 2027. The spectrograph will deliver a minimum resolution of R~5,000 over a simultaneous wavelength range of 310 nm to 1,000 nm with a multiplexing goal of between 20 and 700 targets. The WFOS team consisting of partners in China, India, Japan, and the United States has completed a trade study of two competing concepts intended to meet the design requirements derived from the WFOS detailed science case. The first of these design concepts is a traditional slit mask instrument capable of delivering R~1,000 for up to 100 simultaneous targets using 1 x 7 arc second slits, and a novel focal plane slicing method for R~5,000 on up to 20 simultaneous targets can be achieved by reformatting the 1 arc-second wide slits into three 0.3 arc-second slits projected next to each other in the spatial direction. The second concept under consideration is a highly multiplexed fiber based system utilizing a robotic fiber positioning system at the focal plane containing 700 individual collectors, and a cluster of up to 12 replicated spectrographs with a minimum resolution of R~5,000 over the full pass band. Each collecting element will contain a bundle of 19 fibers coupled to micro-lens arrays that allow for contiguous coverage of targets and adaptation of the f/15 telescope beam to f/3.2 for feeding the fiber system. This report describes the baseline WFOS design, provides an overview of the two trade study concepts, and the process used to down-select between the two options. Also included is a risk assessment regarding the known technical challenges in the selected design concept.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kevin Bundy, Maureen Savage, Renate Kupke, Nicholas MacDonald, Kyle Westfall, Matthew Radovan, Zheng Cai, Brian Digiorgio, Richard Dekany, Devika Divakar, Jason Fucik, Hangxin Ji, Satoshi Miyazaki, Shinobu Ozaki, Andrew Phillips, Namrata Roy, Roger Smith, Arun Surya, S. Sriram, Sivarani Thirupathi, and Toshihiro Tsuzuki "WFOS instrument trade study: slicer vs. fiber instrument concept designs and results (Conference Presentation)", Proc. SPIE 10702, Ground-based and Airborne Instrumentation for Astronomy VII, 1070220 (9 July 2018); https://doi.org/10.1117/12.2312283
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CITATIONS
Cited by 1 scholarly publication.
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KEYWORDS
Spectrographs

Multiplexing

Robotic systems

Thirty Meter Telescope

Astronomical imaging

Fiber couplers

Robotics

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