World's Largest Fully Steerable Radio Telescope Completed in Pocahontas County, West Virginia

The National Radio Astronomy Observatory announces completion of the world’s largest fully steerable radio telescope at Greenbank, Pocahontas County, West Virginia.

The $75 million Green Bank Telescope (GBT) features an innovative design with clear aperture, a collecting area of 2.3 acres, and a computer controlled reflecting surface of 328 ft. X 360 ft. (larger than two football fields).

The GBT is an engineering marvel. At 485 feet tall, it is comparable in height to the Washington Monument. It weighs 16 million pounds (the same as 19 Boeing 747s) yet by swiveling the dish in both azimuth and elevation, it can be pointed to any point in the sky with exquisite accuracy.

The Green Bank Telescope will be used to study everything from the formation of galaxies in the early universe, to the chemical make-up of the dust and gas inside galaxies and in the voids that separate them, to the birth processes of stars. In conjunction with other instruments, it will help make highly accurate radar maps of some familiar objects in our own solar system.

Additionally, the telescope’s two-acre collecting dish has many unique features. Most radio telescopes in use today use receivers suspended above the dish by four struts. These struts block some of the surface of the dish, scattering some of the incoming radio waves from celestial objects under study. The GBT’s offset feed arm has no struts to block incoming radio waves.

The GBT also boasts an active surface. The surface of the dish is composed of 2,004 panels. On the underside of the dish, actuators are located at each corner These actuators are motors that move the surface panels up and down, keeping the shape of the dish precisely adjusted, no matter what the tilt of the telescope. The combination of the telescope’s unblocked aperture and active surface, promise that the GBT will display extremely high sensitivity to faint radio signals.

The Green Bank Telescope itself is not the only precious national resource in Green Bank. The Observatory also administers the National Radio Quiet Zone, which is centered on the NRAO Green Bank site. The Zone extends outward from there, enclosing a land area of approximately 13,000 square miles. This zone is the only one of its kind in the world. Inside it, anything that might interfere with a radio telescope’s sensitive receivers - like cellular phones and radio stations are strictly regulated. This will ensure the GBT clearer reception of radio waves from distant galaxies and the other celestial objects it will study.

The Observatory is one of the leading centers for the growing science of radio astronomy in the United States. It is located in Pocahontas County, WV on Route 92/28, about 35 miles northwest of Marlinton and 53 miles southeast of Elkins. Guided tours are scheduled in season, and cameras are welcome. A self-guided walking tour can be taken anytime. The GBT is approximately 1.5 miles from the Tour Center. Autos are not permitted to drive to the telescope, however, bicycles are permitted on the grounds.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.