VISION: A Six-Telescope Fiber-Fed Visible Light Beam Combiner for the Navy Precision Optical Interferometer
Abstract
Visible-light long baseline interferometry holds the promise of advancing a number of important applications in fundamental astronomy, including the direct measurement of the angular diameters and oblateness of stars, and the direct measurement of the orbits of binary and multiple star systems. To advance, the field of visible-light interferometry requires development of instruments capable of combining more than just two or three beams at once. The Visible Imaging System for Interferometric Observations at NPOI (VISION) is a new visible light beam combiner for the Navy Precision Optical Interferometer (NPOI) that uses single-mode fibers to coherently combine light from up to six telescopes simultaneously with an image-plane combination scheme. It features a photometric camera for calibrations, and spatial filtering from single-mode fibers with two Andor Ixon electron multiplying CCDs. Here we present the VISION system, results of laboratory tests, and results of commissioning on-sky observations. We determine a new set of corrections to the power spectrum and bispectrum when using an electron-multipying CCD to measure visibility and closure phase, by taking into account non-Gaussian statistics and read noise, as required by our post-processing pipeline. We verify our post-processing pipeline via new on-sky observations of the O-type supergiant binary Zeta Orionis A, obtaining a flux ratio, position angle and separation in good agreement with expectations from the previously published orbit.
- Publication:
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American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016
- Bibcode:
- 2016AAS...22734513G