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The CHARA Array


Georgia State University's Center for High Angular Resolution Astronomy operate the CHARA Array on Mount Wilson. The Array consists of six 40-inch (1-m) diameter telescopes distributed along three arms of a Y-shaped configuration encompassed by a circle approximately 400 meters in diameter. As with the Berkeley ISI facility, the CHARA Array is a "long-baseline optical interferometer," but it operates at shorter wavelengths than does the ISI. The Array is the world's most powerful instrument of its kind in terms of its limiting resolution, and is capable of seeing structures on stars previously inaccessible to any telescope. In 2007, CHARA observations produced the first images ever obtained of the surface of another star the size of the sun. Previous stellar images existed only for a handful of stars whose sizes are hundreds of time larger than our parent star.

The CHARA Array was intentionally located on Mount Wilson to take advantage of the site's excellent "astronomical seeing" conditions resulting from normally smooth, laminar air flow from the prevailing winds coming in from the Pacific Ocean. This gives rise to inherently crisp imaging of starlight and enhances the performance of interferometers. While the facility is operated by a full-time staff on Mount Wilson, it is also regularly operated remotely from Atlanta, Paris and Sydney, Australia by member scientists in the CHARA collaboration.

The CHARA website contains extensive information and photographs of this powerful facility.