A Prototype Visible to Near-Infrared Spectrograph for the CHARA Array, a Long-Baseline Stellar Interferometer

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Ogden, Chad Elliott
Interferometer; CHARA; Spectrograph; Visible; Infrared; Diffraction; Astrophysics and Astronomy; Physics
thesis / dissertation description
This work is a description of the Visible to near Infrared Spectrograph system for the CHARA array. The CHARA Array is a 6-telescope interferometer at the Mount Wilson Observatory in the mountains north of Pasadena, California. It combines the light from the 1-meter telescopes, and measures the visibility of the resulting interference fringes, which gives information about the source intensity distribution on the sky. The resolution of the instrument is proportional to the telescope separation, or baseline, divided by the wavelength. The VIS system operates in the 600-1000~nm wavelength range, a factor of 3 to 4 shorter than the standard operating wavelength at CHARA, 2.13 um. An introduction to interferometry is given, with a description of the CHARA Array. The effects of diffraction through the system combined with atmospheric turbulence are described, and the results of a computer model given. The VIS system design is described, and results of the first fringe data are presented, including system visibility and throughput estimates.