Diverse field spectroscopy is a new concept in which any part of a field can be optically captured and send to the entrance slit of a spectrograph. It is more general than integral field spectroscopy, multi-object spectroscopy and even multi-integral-field spectroscopy which combine the two as in the KMOS instrument. In diverse field spectroscopy, point sources and extended sources are simultaneously optically captured in an optimal way that fully use the spectrograph for only the regions of interest; as opposed to multi-integral-field spectroscopy where rectangular or square fields are fully captured, the capturing mechanism will follow the complex shapes of the sources removing any useless field which can then be use for other sources instead or permit to observe larger sources. Optical switches can be programmed to transmit any subset of the spatial elements of a field to the spectrograph. We present the different optical designs of switches that we made, some using micromirrors arrays, others small lenses. We also present conceptual designs of low cost projects for Échelle spectrographs as the SALT HRS and for the FMOS spectrographs on SUBARU. A critical aspect of the designs is to minimize the cost so that the switches can be mass-produced while maintaining high optical performances. A general discussion will be made of the relation between the total cost of the switch system plus spectrograph and the multiplex advantage with respect to an integral-field spectrograph giving the same performances.

Date Published: 22 July 2010
PDF: 9 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 773927 (22 July 2010); doi: 10.1117/12.857939

Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)