Coming Down to Earth
When the 200-foot tall dish telescope in Green Bank, West Virginia needed receiver maintenance, operators drove its 140-foot (43-meter) dish to within four feet of the ground. An engineering tower was winched up until the apex of the telescope was nestled inside. Then, in a protected space, the sensitive equipment was 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. The tower is still used to work on the apex.
Credit: NRAO/AUI/NSF
