GBT

The Green Bank Telescope (GBT) is a radio telescope in Green Bank, West Virginia, United States. It is operated by the National Radio Astronomy Observatory (NRAO) and is the world's largest fully steerable single-dish radio telescope. It was completed in 2000 and began scientific operations shortly thereafter.

The telescope uses a 100-meter parabolic dish with an active surface and a movable secondary reflector as part of a Gregorian optical system, enabling observations across a broad frequency range. Its unblocked aperture design and precise engineering provide high sensitivity and good pointing accuracy across most of the radio spectrum.

GBT's frequency coverage spans from about 290 MHz to 116 GHz, enabling studies of neutral hydrogen, molecular lines, and continuum emission. It supports a suite of backends for spectroscopy, pulsar timing, and imaging, and routinely participates in very long baseline interferometry (VLBI) networks. It has contributed to discoveries including pulsars, fast radio bursts, and surveys of the Milky Way and extragalactic sources.

The GBT is a key facility for radio astronomy in North America, serving universities and research institutions worldwide through NRAO's user programs and data archives. Its operations and upgrades continue to enhance sensitivity, mapping speed, and data-processing capabilities.

In other contexts, GBT can refer to different organizations or technologies, but the Green Bank Telescope remains the principal use of the acronym in astronomy.