FMOS System Overview

FMOS consists of several components which are distributed across the telescope facility as shown in Fig. 1: The fiber positioner system "Echidna" accomodated in the Prime Focus Unit for IR (PIR) is capable of positioning 400 fibers with an accuracy of 0.2 arcsec rms in the circular field of view with a diameter of 30' at the Subaru prime focus. The F/2 beam is received at the prime focus by the fibers in the Echidna system and is converted to F/5 by the re-imaging lens system in the fiber connectors. This F/5 beam is then transmitted by the fiber cables which are installed along the telescope structure down to the elevation axis and up to the floor two levels above the Nasmyth platform (the same level as the telescope top unit). There are two InfraRed Spectrographs ("IRS1" and "IRS2") on this floor each of which makes spectra of the 200 fibers.

Fig. 1 - Configuration of the FMOS components

Readers can also refer to the paper as listed below and references therein for more details of this instrument:

"The Fibre Multi-Object Spectrograph (FMOS) for Subaru Telescope"
Kimura, M., et al. 2010, Publication of The Astronomical Sciety of Japan, Vol. 62, 1135.

Last updated: January 31, 2012

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