The Gemini Remote Access CFHT ESPaDOnS Spectrograph (GRACES) is an innovative instrumentation experiment that will demonstrate if ESPaDOnS, a bench-mounted high-resolution optical spectrograph at CFHT, can be fed by a 270-m long fiber from the Gemini-North telescope with low enough losses to remain competitive with conventional spectrographs on other 8 to 10-m telescopes. Detailed simulations have shown that GRACES should be more sensitive than the HIRES spectrograph at Keck Observatory at wavelengths longer than about 600-700 nm. This result is possible by using FPB-type of optical fibers made by Polymicro Technologies and by keeping the critical focal ratio degradation (FRD) losses to less than 10%. Laboratory tests on these FPB optical fibers are underway and show that for 36-m lengths that the FRD losses are as low as 0.8% with a repeatability of 1%. Tests are currently underway on 280-m lengths.

Date Published: 24 September 2012
PDF: 10 pages
Proc. SPIE 8446, Ground-based and Airborne Instrumentation for Astronomy IV, 84462A (24 September 2012); doi: 10.1117/12.926626

Published in SPIE Proceedings Vol. 8446:
Ground-based and Airborne Instrumentation for Astronomy IV
Ian S. McLean; Suzanne K. Ramsay; Hideki Takami, Editor(s)