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.
Ants on a Plate
From over 200 feet above them, painters look like ants on the 2.3 acre dish of the Green Bank Telescope. Each of the 2004 aluminum panels of the GBT’s surface must be scraped and repainted on a rotating schedule. It takes years to paint the entire telescope, and painters arrive every summer to keep this endless task going. The paint on the GBT is a special blend that reflects sunlight, gives off heat, and its molecules do not give off radio waves.
You Can’t Miss It
The Green Bank Telescope dominates the countryside in Green Bank, West Virginia. At 485-feet tall and over 2 acres across, the GBT is the largest moving land-based object ever built.
Made in America
The Green Bank Telescope is an American treasure. The GBT is the world’s largest, fully-steerable telescope, and anyone can come visit it in Green Bank, West Virginia.