Center for High Angular Resolution Astronomy


Center for High Angular Resolution Astronomy

(CHARA) An optical and infrared long baseline interferometry (LBI) facility operated at the Mount Wilson Observatory, California, by Georgia State University since 1984 with funding from the National Science Foundation and additional support from the W.M. Keck Foundation, the David and Lucille Packard Foundation, and private donations. The center also houses the Mount Wilson Institute, the non-profit corporation that controls the Mount Wilson Observatory by arrangement with the Carnegie Institution of Washington. In 1996 CHARA began construction of an interferometric array of six telescopes on Mount Wilson. The CHARA array became an active science instrument in 2002.

Each of the telescopes linked up in the array has an altazimuth mounting. Each instrument's primary mirror has an aperture of 1 meter. The instruments are deployed in a Y-shaped arrangement on the 1737-meter summit of Mount Wilson so as to form a two-dimensional layout that provides the resolving power of a single telescope with an aperture of up to 350 meters. Operating on dual wavelength regimes, the array has limiting resolutions of 200 μas at 500–800 nm and 1 mas at 2.0–2.4 μm. With these exceptionally high angular resolutions, astronomers should be able to make accurate measurements of the diameters of nearby stars, to detect any orbiting companions and measure the mass of such binary systems, and to contribute to the search for extrasolar planets.