The Green Bank Telescope (GBT) is a 100-meter radio telescope at Green Bank Observatory in West Virginia. It is the world's largest steerable telescope. The current telescope was completed in 2000, replacing the earlier, collapsed, 1962 Green Bank 300ft Telescope (GB300) (likely in its own time called the "Green Bank Telescope"). The current telescope detects frequencies in the range of 290MHz to 100GHz.
Among the instruments are MUSTANG and MUSTANG-2, two successive versions of bolometer arrays and Argus, a 16-pixel focal plane array of W-band radio spectrometers.
Recent projects include 21cm line surveys both within the Milky Way, and extragalactic, e.g., redshifted galaxies and also intensity mapping the DEEP2 field.