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Proceedings Paper

Status of commissioning stabilized infrared Fizeau interferometry with LBTI
Author(s): Eckhart Spalding; Phil Hinz; Katie Morzinski; Steve Ertel; Paul Grenz; Erin Maier; Jordan Stone; Amali Vaz
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Paper Abstract

The Large Binocular Telescope Interferometer (LBTI) has the longest baseline in the world|22.7 m|for performing astronomical interferometry in Fizeau mode, which involves beam combination in a focal plane and preserves a wide field-of-view. LBTI can operate in this mode at wavelengths of 1.5-5 and 8-12 μm, making it a unique platform for carrying out high-resolution imaging of circumstellar disks, and possibly searches for planets, in the thermal infrared. Over the past five years, LBTI has carried out a considerable number of interferometric observations by combining the beams near a pupil plane to carry out nulling interferometry. This mode is useful for measuring small luminosity level offsets, such as those of exozodiacal dust disks. The Fizeau mode, by contrast, is more useful for generating an image of the target because it has more uv plane coverage. However, the Fizeau mode is still in an ongoing process of commissioning. Sensitive Fizeau observations require active phase control, increased automation, and the removal of non-common-path (NCP) differential aberrations. These maximize the fringe contrast, enable longer integrations, and reduce time overheads. We are in the process of writing a correction loop to remove NCP aberrations, and have carried out tests on old and synthetic data. We have also carried out on-sky Fizeau engineering tests in 2018B and 2019A. In this article, we share lessons learned and strategies developed as a result of these tests.

Paper Details

Date Published: 9 September 2019
PDF: 20 pages
Proc. SPIE 11117, Techniques and Instrumentation for Detection of Exoplanets IX, 111171S (9 September 2019); doi: 10.1117/12.2529808
Show Author Affiliations
Eckhart Spalding, The Univ. of Arizona (United States)
Phil Hinz, Univ. of California, Santa Cruz (United States)
Katie Morzinski, The Univ. of Arizona (United States)
Steve Ertel, Large Binocular Telescope Observatory (United States)
The Univ. of Arizona (United States)
Paul Grenz, The Univ. of Arizona (United States)
Erin Maier, The Univ. of Arizona (United States)
Jordan Stone, The Univ. of Arizona (United States)
Amali Vaz, Large Binocular Telescope Observatory (United States)

Published in SPIE Proceedings Vol. 11117:
Techniques and Instrumentation for Detection of Exoplanets IX
Stuart B. Shaklan, Editor(s)

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