Sitting 60 feet above the dish of the 140-foot telescope was this original feed ring. Radio waves bouncing from the 43-meter parabolic dish came to a focus directly where the receiver would have been placed, inside the black cartridge of this ring.
New Digs at the 140-foot
In 1972, the control room of the 140-foot (43-meter) telescope in Green Bank, West Virginia got an upgrade. Gone were the Flash Gordon-looking analog monitors and dials and in their place was this suite of Honeywell 316 computer modules. It had 32 Kb of memory, a card reader for program loading, CRT displays, and a position panel which controlled the telescope’s position, errors, and slew rates. These days, the telescope can be run remotely from the Jansky Lab up the lane or from a laptop stashed in a cabinet in this room.
Anechoic Chamber
Manmade radio signals (from wireless devices, orbiting satellites, spark plugs, microwave ovens, etc.) swamp the weak waves we detect from objects out in space. Before we install any piece of equipment in Green Bank, we test it in this special room called an anechoic chamber. The pedestal in the foreground holds the device to be tested, and an antenna at the back of the room picks up its radio waves, if any. The foam cones covering walls, floors, and ceilings break up radio waves that are not in direct line with the antenna. Any radio-leaking electronics are encased before they are brought close to the telescopes.
Inside the Interference Hunting Van
Inside the van used by staff to track down sources of radio frequency interference across the West Virginia countryside. Sophisticated receiver equipment nestles in racks, and in 1981-style, is decorated with wood paneling.
Little Big Horn
The Calibration Horn Antenna, nicknamed the “Little Big Horn,” at Green Bank in 1967. As its name implies, this 120-foot long horn antenna was used to measure the intensity of radio waves coming from the sky’s strongest non-solar radio source, Cassiopeia A. The Calibration Horn measured a total power output for Cas A at a frequency of 1.4 GHz (a wavelength of 20cm), and thus provided astronomers with a standard reference point on the sky against which they could measure other sources.
Tab A Goes Into Slot A
The backup structure of the Green Bank Telescope is an engineering marvel. This crisscross of beams carries an array of 2209 small motors that support the GBT’s 2.3-acre surface of aluminum plates.