Building the world’s largest polar-aligned telescope is no simple or small task. This concrete bunker is the control building and base pedestal for the 140-foot (43-meter) telescope in Green Bank, West Virginia. The reinforced concrete base uses 140 tons of steel inside 5700 tons of 5000-psi concrete. It was built on the bedrock 30 feet below the surface in order to keep the 8200-ton telescope from falling over. The telescope’s control room, offices, and hydraulic pumps were housed inside the 3-foot thick walls of this monstrous building.
Switching out the 140-foot telescope’s receivers
The 140-foot telescope in Green Bank was built to house its receivers at the Prime Focus, the point above the parabolic dish where the radio waves come together. To switch receivers of different wavelengths, the 43-meter dish was lowered, a tower was rolled to the Prime Focus, and staff climbed it to make the careful swap. Now, the telescope’s receivers nestle in the center of the dish, and a small reflecting mirror sits at the prime focus.
Maintenance on the 140-ft Polar Shaft
The largest polar shaft of any telescope in the world is a part of the 140-foot (43-meter) radio telescope in Green Bank, West Virginia. Its surface is covered in thermal insulating foam, the same foam used by the Space Shuttles’ External Tanks. Over time it cracks and flakes, so a crew (like the one pictured here) comes in to remove and reapply the foam.
Collapsed metal of the 300-foot telescope
On the night of November 15, 1988, the 300-foot telescope in Green Bank, West Virginia collapsed. The extent of the damage was not known until the Sun rose on the scene. This photo shows the incredible ruin of folded steel that greeted the staff in the morning.
Wide shot of the collapsed 300-foot telescope
At 9:43 pm on November 15, 1988, the 300-foot telescope collapsed on top of its control building. No-one was hurt, but the telescope was destroyed. After an investigation, officials found a metal plate deep inside the telescope had finally worn out, and its position was critical to the structure.
The last photograph of the 300-foot telescope intact
This is the last photograph of the 300-foot showing it intact. It was taken on the afternoon of November 15, 1988, hours before the giant dish collapsed.