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Proceedings Paper

Multi-object medium resolution optical spectroscopy at the E-ELT
Author(s): Paolo Spanò; Piercarlo Bonifacio
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Paper Abstract

We present the design of a compact medium resolution spectrograph (R~15,000-20,000), intended to operate on a 42m telescope in seeing-limited mode. Our design takes full advantage of some new technology optical components, like volume phase holographic (VPH) gratings. At variance with the choice of complex large echelle spectrographs, which have been the standard on 8m class telescopes, we selected an efficient VPH spectrograph with a limited beam diameter, in order to keep overall dimensions and costs low, using proven available technologies. To obtain such a resolution, we need to moderately slice the telescope image plane onto the spectrograph entrance slit (5-6 slices). Then, standard telescope AO-mode (GLAO, Ground Layer Adaptive Optics) can be used over a large field of view (~10 arcmin), without loosing efficiency. Multiplex capabilities can greatly increase the observing efficiency. A robotic pick-up mirror system can be implemented, within conventional environmental conditions (temperature, pressure, gravity, size), demanding only standard mechanical and optical tolerances. A modular approach allows us scaling multiplex capabilities on overall costs and available space.

Paper Details

Date Published: 11 July 2008
PDF: 8 pages
Proc. SPIE 7014, Ground-based and Airborne Instrumentation for Astronomy II, 70144D (11 July 2008);
Show Author Affiliations
Paolo Spanò, INAF-Osservatorio Astronomico di Brera (Italy)
Piercarlo Bonifacio, CIFIST Marie Curie Excellence Team (France)
GEPI, Observatoire de Paris, CNRS, Univ. Paris Diderot (France)
INAF-Osservatorio Astronomico di Trieste (Italy)

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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