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Proceedings Paper

Improved design and prototyping for a 10/20-um camera/spectrometer for ESO's VLT
Author(s): Hans-Ulrich Kaeufl; Bernard Delabre
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Paper Abstract

The Cassegrain focus of the 2nd unit telescope of ESO's VLT shall be equipped with a 10/20 micrometers camera spectrometer. This instrument shall be built by a consortium of institutes from ESO's member-states responsible for the final design. Still rather detailed internal studies were required to assess the overall scope of work, the repercussions on the telescope design and the required infrastructure at ESO. The internal studies have resulted in a multimode instrument allowing for diffraction limited imaging with variable magnification at 10/20 micrometers , low-, medium- plus potentially high-resolution long slit spectroscopy (approaching or exceeding (lambda) divided by (Delta) (lambda) approximately equals 50000). The optical design allows to take advantage of the rapid evolution in the field of detectors. Novel design features are an exchangeable entrance window, an anamorphic beam expansion and potentially the use of immersion gratings. At the La Silla observatory TIMMI, a small 10 micrometers camera/spectrometer for the 3.6 m telescope (built by the Service d'Astrophysique, CEN- Saclay, France) is in operation to allow both ESO and its community to gain practical experience in astronomy in the 10 micrometers atmospheric window. This instrument is currently equipped with a 64x64 element Ga:Si array. A 128x196 element array is presently in development at Leti/LIR of Grenoble, France, which may be used to upgrade ESO's current observing capabilities. Spectroscopy in TIMMI utilizes Germanium grisms machined via anisotropic etching. This manufacturing technology may also serve to fabricate immersion gratings from high index materials.

Paper Details

Date Published: 1 June 1994
PDF: 12 pages
Proc. SPIE 2198, Instrumentation in Astronomy VIII, (1 June 1994); doi: 10.1117/12.176795
Show Author Affiliations
Hans-Ulrich Kaeufl, European Southern Observatory (Germany)
Bernard Delabre, European Southern Observatory (Germany)

Published in SPIE Proceedings Vol. 2198:
Instrumentation in Astronomy VIII
David L. Crawford; Eric R. Craine, Editor(s)

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