The 2.3-acre dish of the Green Bank Telescope is the largest moving object on land. The telescope’s unique design places its receivers off the edge, at the top in this photo, to keep them from blocking incoming radio waves from hitting the dish.
How Low Can It Go?
The Green Bank Telescope was designed to see 85% of the entire skies visible around the Earth. As in this photo, the GBT can dip extremely low to capture data coming from very southern sections of the sky, especially toward the center of our Milky Way Galaxy, where the GBT has found rich, complex chemistry.
Symmetry in Steel
Over 13,000 steel beams support the world’s largest fully-steerable telescope in Green Bank, West Virginia. The Green Bank Telescope weighs 17 million pounds, and moves on a rotating base and a tilting gear. The two-armed yoke at the base of the GBT supports the tilting gear. And a gigantic arm attaches behind the dish to give it strength to tower over 200 feet above the surface.
Fully-Steerable GBT
The 110-meter dish of the Green Bank Telescope can be aimed all over the sky, thanks to its rotating base and a huge tilting gear. It is the largest, fully-steerable telescope in the world and the largest moving object ever built on land.
Long Arm of the Feed
The triangular-shaped trusswork towering above the Green Bank Telescope (GBT) holds a mirror-like dish just visible at the top. Radio waves bounce off the 110-meter telescope surface and head up to this small mirror. The mirror, called a sub-reflector, sends those waves straight into a feed of one of eight receivers suspended in the small building between the towers.
Beneath the Turret
The receivers of the Green Bank Telescope (GBT) hang from a rotating turret. To change to a new receiver, the radio astronomy equivalent of changing the channel, the turret is spun until the desired receiver is aimed underneath the beam of waves coming from the directional mirror above.