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Session 9 - Instruments, Techniques.
Display session, Monday, June 09
South Main Hall,
The CHARA Array is a five element interferometer in the process of being built on Mount Wilson, north of Los Angeles, CA. The Array will be in a Y-shaped configuration to maximize UV-plane coverage, a good feature for imaging. The telescopes are actually the first of two beam-reduction stages, the first being an 8:1 reduction, and the second being a 5:1 reduction. Between the two reduction stages, each of the five beams passes through its own Optical Path Length Equalizer (OPLE) to insure that all five beams are mutually phase equalized. After the second stage of beam reduction there are five beams, each 25 mm in diameter, physically evenly spaced, and phase equalized, allowing much flexibility in choices of scientific data collection techniques.
Presented are some preliminary results in the development of a prototype imager for the Array. This imager uses single-mode fiber optics (used to preserve the phase) to convert from the rather wide, evenly spaced beams to smaller (in the realm of commercial optics), non-redundantly spaced beams. Because the spacing of the beams is in one dimension, the other dimension is used to disperse the fringes, increasing bandwidth. Techniques not unlike those used in radio interferometry will be used to create the object image from the raw data produced by the imager.
Program listing for Monday