12 April 2017 Optics alignment of a balloon-borne far-infrared interferometer BETTII
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The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-m baseline far-infrared (FIR: 30 90    μ m ) interferometer providing spatially resolved spectroscopy. The initial scientific focus of BETTII is on clustered star formation, but this capability likely has a much broader scientific application. One critical step in developing an interferometer, such as BETTII, is the optical alignment of the system. We discuss how we determine alignment sensitivities of different optical elements on the interferogram outputs. Accordingly, an alignment plan is executed that makes use of a laser tracker and theodolites for precise optical metrology of both the large external optics and the small optics inside the cryostat. We test our alignment on the ground by pointing BETTII to bright near-infrared sources and obtaining their images in the tracking detectors.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Arnab Dhabal, Stephen A. Rinehart, Maxime Rizzo, Lee G. Mundy, Henry P. Sampler, Roser Juanola-Parramon, Todd J. Veach, Dale J. Fixsen, Jordi Vila Hernandez de Lorenzo, Robert F. F. Silverberg, "Optics alignment of a balloon-borne far-infrared interferometer BETTII," Journal of Astronomical Telescopes, Instruments, and Systems 3(2), 024002 (12 April 2017). https://doi.org/10.1117/1.JATIS.3.2.024002 . Submission: Received: 20 January 2017; Accepted: 27 March 2017
Received: 20 January 2017; Accepted: 27 March 2017; Published: 12 April 2017

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