Feed Tower of the 140-foot
When the 200-foot tall telescope in Green Bank, West Virginia needs feed maintenance, operators drive its 140-foot (43-meter) dish to within four feet of the ground and set its parking brakes. An engineering tower is winched on railway wheels until the apex of the telescope is nestled inside. Then, in a protected space, the sensitive equipment can be removed, replaced, and finely adjusted. These days, the 140-foot has not been using a receiver at its apex. Instead, a sophisticated second reflector sits here to bounce waves to receivers nestled in the hole in the center of the dish.
Credit: T. Burchell, NRAO/AUI/NSF
