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Proceedings Paper

Cryogenic beam-combiner for very low background 2- to 20-um interferometry on the 22.8-m Large Binocular Telescope
Author(s): Donald W. McCarthy; Erin M. Sabatke; Roland J. Sarlot; Philip M. Hinz; James H. Burge
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Paper Abstract

The 22.8 m Large Binocular Telescope Interferometer will be a uniquely powerful tool for imaging and nulling interferometry at thermal infrared wavelengths (2 - 20 micrometers ) because of the LBT's unusual combination of low emissivity, high spatial resolution, broad (u,v)-plane coverage, and high photometric sensitivity. The gregorian adaptive secondary mirrors permit beam combination after only three warm reflections. They also control the relative pathlength, wavefront tip/tilt, and focus of the two telescope beams, thus greatly simplifying the complexity of the beam-combiner. The resulting four-mirror beam-combiner reimages the original focal plane and also images the telescope pupil onto a cold stop to limit thermal background. At first-light in 2004, an all-reflective, cooled beam-combiner can provide a 2 arcmin diameter field for Fizeau-style imaging as well as the low thermal background and achromaticity required for nulling interferometry.

Paper Details

Date Published: 5 July 2000
PDF: 14 pages
Proc. SPIE 4006, Interferometry in Optical Astronomy, (5 July 2000); doi: 10.1117/12.390267
Show Author Affiliations
Donald W. McCarthy, Steward Observatory/Univ. of Arizona (United States)
Erin M. Sabatke, Optical Sciences Ctr./Univ. of Arizona (United States)
Roland J. Sarlot, Steward Observatory/Univ. of Arizona (United States)
Philip M. Hinz, Steward Observatory/Univ. of Arizona (United States)
James H. Burge, Steward Observatory/Univ. of Arizona and Optical Sciences Ctr./Univ. of Arizona (United States)

Published in SPIE Proceedings Vol. 4006:
Interferometry in Optical Astronomy
Pierre J. Lena; Andreas Quirrenbach, Editor(s)

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