The Arecibo 305-m Telescope: 57 Years of Unprecedented Discovery

Commissioned in November 1963, the Arecibo 305-m radio telescope reinvented itself several times over the next 57 years via a series of upgrades. These effectively provided its global user community with a new facility on each occasion. Solid aluminum panels replaced its wire mesh primary surface from 1972 to 74. In the mid-1990s, its narrow-band line-feeds were superseded by a fully-achromatic two-mirror system in a geodetic dome. Together with other improvements, this enabled operations up to 10 GHz. A new powerful S-band radar transmitter led to remarkable studies of near-Earth asteroids. In 2005, a 7-beam, L-band, focal-plane array was added to the suite of receivers, resulting in over a decade of major sky-survey observations. Sadly, telescope operations ceased with the collapse of the suspended platform in Dec. 2020.