List of largest optical telescopes in Ireland and the United Kingdom is a list of the largest optical telescopes in the British Isles, including in the United Kingdom and Ireland.
The most famous telescopes include Herschel's reflector, with which he discovered Georgium Sidus (the planet Uranus), and the Leviathan of Parsonstown which at 1.83 meters (72 inches) was for decades the largest aperture telescope in the World. In the 20th century many older telescopes are popular tourist attractions, such as at Royal Observatory in Greenwich, London. There are also a number of modest instruments at universities used for various astronomical projects or education.
The largest optical telescope in Britain was the Isaac Newton Telescope which had a 98 inches (2.5 m) mirror; it was located at the Royal Greenwich Observatory, Herstmonceux from 1965 to 1980, but was then relocated to Roque de los Muchachos Observatory on La Palma, Canary Islands.
The list is not really representative of the largest telescopes operated by the United Kingdom or Ireland, which by the 20th century were building large telescopes overseas or in the southern hemisphere for better weather or other reasons.
The following is a non-comprehensive list of optical telescopes currently located in the British Isles with an aperture of 24 inches or greater:
Name | Effective aperture | Type | Location | Operator | First light | Comments |
---|---|---|---|---|---|---|
Rosse Six Foot Telescope (reconstructed) [1] | 72 in (183 cm) | Newtonian reflector | Birr, Leinster, Ireland | Birr Castle | 1999 | Largest optical telescope in Ireland |
38-inch Congo Schmidt [2] | 38 in (96.5 cm) | Reflector | Herstmonceux, East Sussex, England | The Observatory Science Centre | 1960 | Largest optical telescope in UK, but never used due to flawed optics |
James Gregory Telescope[3] | 37 in (94.0 cm) | Cassegrain reflector | St Andrews, Fife, Scotland | University of St Andrews | 1962 | Largest operational optical telescope in the UK |
Cambridge 36-Inch telescope[4] | 36 in (91.4 cm) | Reflector | Cambridge, Cambridgeshire, England | University of Cambridge | 1955 | Largest optical telescope still in use in England |
36-inch Yapp telescope[5] | 36 in (91.4 cm) | Reflector | Herstmonceux, East Sussex, England | The Observatory Science Centre | 1932 | |
Edinburgh 36-inch telescope [6] | 36 in (91.4 cm) | Reflector | Edinburgh, Scotland | Royal Observatory Edinburgh | 1930 | No longer operational |
34-inch Hewitt Camera [7] | 34 in (86.4 cm) | Reflector | Herstmonceux, East Sussex, England | The Observatory Science Centre | 1950s | |
Perren Telescope [8] | 31.5 in (80.0 cm) | Ritchey–Chrétien reflector | Mill Hill, London, England | UCL Observatory | 2019 | |
Thomson/Regan/Owen Reflector | 30 in (76.2 cm) | Reflector | Great Sutton, Cheshire | David Thomson | 2023 | 30 inch F3 telescope on AltAz GOTO mount. Fully homemade including the optics. Fitted with multiple instruments and a high resolution spectrograph |
John Wall refractor [9] | 30 in (76.2 cm) | Refractor | Hanwell, Oxfordshire, England | Hanwell Community Observatory | 1999 | Largest refractor in the British Isles |
30" Dobsonian [10] | 30 in (76.2 cm) | Reflector | Todmorden, West Yorkshire, England | The Astronomy Centre | 1986 | |
Thompson 30-inch Reflector [11] | 30 in (76.2 cm) | Reflector | Herstmonceux, East Sussex, England | The Observatory Science Centre | 1896 | |
Greenwich 28 inch refractor[12] | 28 in (71.1 cm) | Refractor | Greenwich, London, England | Royal Observatory, Greenwich | 1893 | |
Moses Holden Telescope [13] | 27.6 in (70.1 cm) | Reflector | Preston, Lancashire, England | University of Central Lancashire | 2015 | |
Thompson 26-inch Refractor [14] | 26 in (66.0 cm) | Refractor | Herstmonceux, East Sussex, England | The Observatory Science Centre | 1897 | |
24 / 17" Schmidt Camera [15] | 24 in (61.0 cm) | Reflector | Knighton, Powys, Wales | The Spaceguard Centre | 1950 | Largest optical telescope in Wales |
Thornton Telescope [16] | 24 in (61.0 cm) | Reflector | Keele, Staffordshire, England | Keele University | 1975 | |
24" Telescope [17] | 24 in (61.0 cm) | Reflector | Bayfordbury, Hertfordshire, England | University of Hertfordshire | 2021 |
A noted accomplishment of the biggest telescope at the time, Ross's "six foot" leviathan, was the observation of the spiral structure of M51, which was presented at Cambridge in the summer of 1845.[23] Herschel was quite prolific discovering a planet and many moons of the Solar system also with his reflectors.