The Green Bank Observatory (previously National Radio Astronomy Observatory, Green Bank) is an astronomical observatory located in the National Radio Quiet Zone in Green Bank, West Virginia, U.S. It is the operator of the Robert C. Byrd Green Bank Telescope, the world's largest fully steerable radio telescope.

The observatory was established as the National Science Foundation's (NSF) National Radio Astronomy Observatory (NRAO) in 1956 and made its first observations in 1958. It served as the NRAO's headquarters until 1966, after which the facility was known as the National Radio Astronomy Observatory, Green Bank.

In October 2016, the observatory became an independent institution following a 2012 recommendation that the NSF fully divest itself from the facility by October 1, 2016.

Green Bank Observatory subsequently retained partial NSF funding, established private contracts, and formed a partnership with West Virginia University. It is operated by the nonprofit Associated Universities, Inc., under a cooperative agreement with the National Science Foundation.

Active telescopes

• Robert C. Byrd Green Bank Telescope
• 140 Foot (43m) Telescope
• 20 Meter Telescope
• 40 Foot Telescope

Historic and other telescopes

• 300 Foot Radio Telescope – the world's largest moving telescope, suddenly collapsed in November 1988 from the loss of a gusset plate
• Green Bank Interferometer
• Reber Radio Telescope – designated a National Historic Landmark in 1989
• Howard E. Tatel Radio Telescope — utilized in Project Ozma in 1960, the first search for extraterrestrial intelligence (SETI) with a radio telescope
• 45 Foot Telescope

See also

• List of astronomical observatories