Arecibo Observatory

Prior to its decommissioning and sudden collapse, this huge dish made many invaluable contributions to astronomy

THE SPECS

Dish diameter: 305 metres (1,000 feet)

Curvature radius: 265 metres (870 feet)

Number of panels: 38,778

Transmission power: 20TW at 2380MHz

Receiver weight: 900 tonnes

Receiver height: 150 metres (492 feet)

Official opening: 1 November 1963

Decommission order: 19 November 2020

Welcome to the National Astronomy and Ionosphere Center, better known as the Arecibo Observatory. The observatory’s 305-metre (1,000foot) radio telescope dish was completed in 1963, but in November 2020 it was flagged for decommissioning and eventual demolition.

Until 2016 it was the world’s largest singleaperture telescope, and it was involved in many exciting radio astronomy discoveries, as well as collecting data in an attempt to detect alien life. It appeared in many films, video games and TV shows and once boasted a visitor centre that welcomed nearly 100,000 visitors a year.

Nestled in the rainforest of Puerto Rico inside a depression left by a sinkhole, the huge dish antenna has its roots in a 1950s missile defence program. The problem was that incoming nuclear weapons could drop radar decoys as they reentered the atmosphere, making it impossible to tell which were real and which were decoys. By studying the upper levels of the atmosphere it was hoped enough knowledge could be gleaned to tell the bombs from the duds. Early in its life, the telescope also helped locate Soviet radar installations by detecting their signals bouncing off the Moon.