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Simultaneous water vapor and dry air optical path length measurements and compensation with the large binocular telescope interferometer

The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feedforward approach to stabilize the path length fluctuations seen by the LBTI nuller.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/622520
Date04 August 2016
CreatorsDefrère, D., Hinz, P., Downey, E., Böhm, M., Danchi, W. C., Durney, O., Ertel, S., Hill, J. M., Hoffmann, W. F., Mennesson, B., Millan-Gabet, R., Montoya, M., Pott, J.-U., Skemer, A., Spalding, E., Stone, J., Vaz, A.
ContributorsUniv Arizona, Steward Observ, Univ Arizona, Large Binocular Telescope Observ, Univ. of Arizona (United States), Univ. of Arizona (United States), Univ. of Arizona (United States), Univ. of Stuttgart (Germany), NASA Goddard Space Flight Ctr. (United States), Univ. of Arizona (United States), Univ. of Arizona (United States), Univ. of Arizona (United States), Univ. of Arizona (United States), California Institute of Technology (United States), California Institute of Technology (United States), Univ. of Arizona (United States), Max-Planck-Institute for Astronomy (Germany), Univ. of California, Santa Cruz (United States), Univ. of Arizona (United States), Univ. of Arizona (United States), Univ. of Arizona (United States)
PublisherSPIE-INT SOC OPTICAL ENGINEERING
Source SetsUniversity of Arizona
LanguageEnglish
Detected LanguageEnglish
TypeArticle
Rights© 2016 SPIE
Relationhttp://proceedings.spiedigitallibrary.org/proceeding.aspx?doi=10.1117/12.2233884

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