Green Bank Telescope - unique features and their effectiveness

The Green Bank Telescope (GBT) was commissioned in early 2001 and has resulted in a number of scientific publications during its 13 years´ of operation. Pulsars, nature of dark energy, galaxy formation, black holes and Hubble Constant are some examples of research discoveries made with the GBT. The GBT is a fully steerable telescope with a double-offset reflector design. The main reflector is completely unblocked and has a projected aperture of 100 meters in diameter. The subreflector is a section of an ellipsoid 7.55×7.95 meters in size. The telescope operates at prime focus from 290 MHz to 1200 MHz and at secondary focus in the 1.15 GHz to >100 GHz range. The main reflector has about 2000 actuators that are used to compensate for deformations mainly due to gravity and in some cases due to thermal effects.