Center for High Angular Resolution Astronomy (CHARA)
Georgia State University

Contact: Gail Schaefer, Associate Director and Visitor Support Scientist
Phone: 626-500-0012

The Center for High Angular Resolution Astronomy (CHARA) is the optical interferometric array of six telescopes located on Mount Wilson, California.

Each telescope of the CHARA Array has a light-collecting mirror 1-meter in diameter. The telescopes are dispersed over the mountain to provide a two-dimensional layout that provides the resolving capability (but not the light collecting ability!) of a single telescope with a diameter of 330 meters (one fifth of a mile)!

Light from the individual telescopes is transported through vacuum tubes to a central Beam Synthesis Facility in which the six beams are combined together. When the paths of the individual beams are matched to an accuracy of less than one micron, after the light traverses distances of hundreds of meters, the Array then acts like a single coherent telescope for the purposes of achieving exceptionally high angular resolution.

The Array is capable of resolving details as small as 200 micro-arcseconds, equivalent to the angular size of a nickel seen from a distance of 10,000 miles. In terms of the number and size of its individual telescopes, its ability to operate at visible and near infrared wavelengths, and its longest baselines of 330 meters, the CHARA Array is arguably the most powerful instrument of its kind in the world.

The facility is composed of six 1-meter telescopes, a beam synthesis facility, and a beam combination laboratory. Using the longest 331-meter baselines CHARA can resolve objects as small as 0.2 milliarcseconds (mas) at visible wavelengths.

CHARA Array six telescopes

More about this core facility at Georgia State University's website »


More details on accessing and scheduling observations using the CHARA Array.

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