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Proceedings Paper

Measuring the effective wavelength of CHARA classic
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Paper Abstract

This paper presents the first empirical measurement of the K1-band effective wavelength and bandwidth of the CHARA Classic beam combiner on the CHARA Array. Prior to this work, the accepted effective wavelength value used for CHARA Classic data (2.1501μm) came from a model of the system; it was not derived from measurements done on the system directly. We employ two data collection methods for our observations: using the Optical Path Length Equalizer (OPLE) cart to scan through the interference fringes and using the dither mirror to scan through the fringes. The two observational methods yield similar effective wavelength measurements (2.141±0.003μm with the OPLE cart and 2.136±0.002μm with the dither mirror). Both of these results are lower than the previously adopted effective wavelength value, but by less than 0.7%. The bandwidth values measured by the two methods differ from each other by almost 5% (0.334 ± 0.002μm with the OPLE cart and 0.351±0.003μm with the dither mirror). Our results establish the first estimate of the uncertainty in the effective wavelength and bandwidth.

Paper Details

Date Published: 21 July 2010
PDF: 15 pages
Proc. SPIE 7734, Optical and Infrared Interferometry II, 77342W (21 July 2010); doi: 10.1117/12.856141
Show Author Affiliations
Emily C. Bowsher, Georgia State Univ. (United States)
Harold A. McAlister, Georgia State Univ. (United States)
Theo A. ten Brummelaar, The CHARA Array, Mount Wilson Observatory (United States)

Published in SPIE Proceedings Vol. 7734:
Optical and Infrared Interferometry II
William C. Danchi; Françoise Delplancke; Jayadev K. Rajagopal, Editor(s)

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