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Proceedings Paper

Developments in high-density Cobra fiber positioners for the Subaru Telescope’s Prime Focus Spectrometer
Author(s): Charles D. Fisher; David F. Braun; Joel V. Kaluzny; Michael D. Seiffert; Richard G. Dekany; Richard S. Ellis; Roger M. Smith
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Paper Abstract

The Prime Focus Spectrograph (PFS) is a fiber fed multi-object spectrometer for the Subaru Telescope that will conduct a variety of targeted surveys for studies of dark energy, galaxy evolution, and galactic archaeology. The key to the instrument is a high density array of fiber positioners placed at the prime focus of the Subaru Telescope. The system, nicknamed “Cobra”, will be capable of rapidly reconfiguring the array of 2394 optical fibers to the image positions of astronomical targets in the focal plane with high accuracy. The system uses 2394 individual “SCARA robot” mechanisms that are 7.7mm in diameter and use 2 piezo-electric rotary motors to individually position each of the optical fibers within its patrol region. Testing demonstrates that the Cobra positioner can be moved to within 5μm of an astronomical target in 6 move iterations with a success rate of 95%. The Cobra system is a key aspect of PFS that will enable its unprecedented combination of high-multiplex factor and observing efficiency on the Subaru telescope. The requirements, design, and prototyping efforts for the fiber positioner system for the PFS are described here as are the plans for modular construction, assembly, integration, functional testing, and performance validation.

Paper Details

Date Published: 13 September 2012
PDF: 8 pages
Proc. SPIE 8450, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II, 845017 (13 September 2012); doi: 10.1117/12.927161
Show Author Affiliations
Charles D. Fisher, Jet Propulsion Lab. (United States)
David F. Braun, Jet Propulsion Lab. (United States)
Joel V. Kaluzny, Jet Propulsion Lab. (United States)
Michael D. Seiffert, Jet Propulsion Lab. (United States)
Richard G. Dekany, Caltech Optical Observtaries (United States)
Richard S. Ellis, California Institute of Technology (United States)
Roger M. Smith, California Institute of Technology (United States)

Published in SPIE Proceedings Vol. 8450:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation II
Ramón Navarro; Colin R. Cunningham; Eric Prieto, Editor(s)

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