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

D. Defrère, P. Hinz, E. Downey, M. Böhm, W. C. Danchi, O. Durney, S. Ertel, J. M. Hill, W. F. Hoffmann, B. Mennesson, R. Millan-Gabet, M. Montoya, J. U. Pott, A. Skemer, E. Spalding, J. Stone, A. Vaz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations

Abstract

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.

Original languageEnglish (US)
Title of host publicationOptical and Infrared Interferometry and Imaging V
EditorsMichelle J. Creech-Eakman, Fabien Malbet, Peter G. Tuthill
PublisherSPIE
ISBN (Electronic)9781510601932
DOIs
StatePublished - 2016
EventOptical and Infrared Interferometry and Imaging V - Edinburgh, United Kingdom
Duration: Jun 27 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9907
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherOptical and Infrared Interferometry and Imaging V
CountryUnited Kingdom
CityEdinburgh
Period6/27/167/1/16

Keywords

  • ELT
  • Fringe tracking
  • Infrared interferometry
  • LBT
  • Nulling interferometry
  • Water vapor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Defrère, 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. (2016). Simultaneous water vapor and dry air optical path length measurements and compensation with the large binocular telescope interferometer. In M. J. Creech-Eakman, F. Malbet, & P. G. Tuthill (Eds.), Optical and Infrared Interferometry and Imaging V [99071G] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9907). SPIE. https://doi.org/10.1117/12.2233884