Physics Colloquium
Friday, October 24th, 2003 4 P.M.

Harold A McAlister

Department of Physics and Astronomy
Georgia State University

The CHARA Array on Mt. Wilson

Georgia State University's Center for High Angular Resolution Astronomy operates the CHARA Array on the grounds of Mt. Wilson Observatory. The Array consists of six 1-m aperture telescopes arranged in a Y-shaped configuration yielding interferometric baselines ranging from 31 to 330 meters; the latter providing the longest baseline andhence highest resolution of any operational interferometer in the world. Construction of the Array began in 1996 and commissioning scientific observations were initiated in 2002. The scientific goals of the instrument relate to the determination of fundamental astrophysical parameters of stars such as masses, diameters, and temperatures. Funding for the CHARA Array was provided by the National Science Foundation, the W.M. Keck Foundation, the David and Lucile Packard Foundation and Georgia State University. This talk will follow a photon's path through the instrument, describe the various subsystems that keep it going in the right direction and demonstrate the outcome of its successful combination with another photon collected by a second telescope. Information about the CHARA Array, including numerous technical descriptions, can be found at www.chara.gsu.edu/CHARA.

Refreshments 3:30 P.M. Room E200 Math/Science Center