Radio Astronomy Observatories From Jodrell Bank to MeerKAT

Jodrell Bank in Cheshire became operational in mid-1957 around the Lovell Telescope, a 76-meter steerable dish that was the largest of its kind at completion. It tracked Sputnik and early spacecraft, which made radio astronomy a public part of the space age.

The Mullard Observatory near Cambridge was opened on 25 July 1957. Its arrays under Martin Ryle and Antony Hewish pioneered aperture synthesis, the imaging technique behind most modern radio telescopes, and Hewish and Jocelyn Bell Burnell found the first pulsar there in 1967.

The Algonquin Radio Observatory in Ontario opened in 1959 and is built around a 46-meter dish. It took a pioneering part in Very Long Baseline Interferometry between Canadian and American telescopes in the late 1960s, an idea that later grew into continent-sized arrays.

This Canadian facility near Penticton, British Columbia, was founded in 1960. Its site houses an interferometric radio telescope, a 26-meter single dish and the Canadian Hydrogen Intensity Mapping Experiment, and its synthesis array has been used for large surveys of neutral hydrogen gas.

Parkes in New South Wales was completed in 1961 and centers on a 64-meter movable dish nicknamed The Dish. It received live television transmissions of the 1969 Apollo 11 Moon landing and remains one of the most productive Southern Hemisphere instruments for pulsar surveys.

Arecibo opened in 1963 as a dish built into a natural sinkhole in Puerto Rico and was the largest single-aperture telescope in the world until 2016. It contributed to the discovery of the first binary pulsar and sent the 1974 Arecibo message. Its main structure collapsed in 2020.

The Westerbork array in the Netherlands was completed in 1970 as an aperture synthesis interferometer of fourteen 25-meter dishes in a line. It observes radio waves between 120 megahertz and 8.3 gigahertz and still serves as a technical testbed for LOFAR and the Square Kilometre Array.

Effelsberg in Germany was inaugurated on 1 August 1972 with a fully steerable 100-meter dish, the largest steerable radio telescope in the world for nearly three decades. Run by the Max Planck Institute for Radio Astronomy, it is still a leading instrument for pulsar timing and VLBI.

The Very Large Array in New Mexico, in operation from 1980, combines 27 movable dish antennas into a single large radio telescope. The antennas can be repositioned to give up to 351 independent baselines, so the array is in effect a telescope whose size can be changed.

Nobeyama in Nagano, Japan, is a millimeter-wave observatory whose 45-meter single-dish telescope observes at short millimetre wavelengths. Its 1982 completion shows radio astronomy moving from long wavelengths toward the shorter waves that reveal cool gas and dust.

The Very Long Baseline Array was completed in May 1993 as ten identical 25-meter dishes spread from Hawaii to the US Virgin Islands. Their signals are combined after the fact to act like a telescope as large as a continent, with some of the sharpest resolution of any astronomical instrument.

The Giant Metrewave Radio Telescope near Narayangaon, India, is an array of thirty fully steerable 45-meter dishes completed in the 1990s. It observes at metre wavelengths with baselines of up to 25 kilometres, which suits studies of distant galaxies, pulsars and the early universe.

The Green Bank Telescope in West Virginia began regular science operations in 2001 and is the world's largest fully steerable radio telescope, surpassing Effelsberg. Its unblocked 100-by-110-meter dish sits inside the National Radio Quiet Zone, where transmissions are restricted to protect it.

FAST in Guizhou, China, was finished when its last panel was installed on 3 July 2016. Its 500-meter dish sits in a natural karst depression and surpassed Arecibo as the largest filled-aperture radio telescope, using an active surface of 4,500 metal panels that reshapes in real time.

MeerKAT was inaugurated on 13 July 2018 as sixty-four 13.5-meter dishes in South Africa's Karoo, and it is now part of the Square Kilometre Array. It has produced some of the most detailed radio images of the center of the Milky Way, closing the path on the array era.