The Green Bank Interferometer (GBI) is operated by the National Radio Astronomy Observatory (NRAO) at its Green Bank site in West Virginia. It includes three radio telescopes of 85-foot (26m) diameter, designated 85-1, 85-3, and 85-2. (85-1 is also known as the Tatel Telescope.) At present, 85-3 is devoted to continuous monitoring of pulsars; 85-1 and 85-2 form a one-baseline interferometer.
Note: the GBI monitoring program has ceased as of October 6, 2000, due to lack of funding.