List of largest optical telescopes in the British Isles explained

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 98inch 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.

Current list

The following is a non-comprehensive list of optical telescopes currently located in the British Isles with an aperture of 24 inches or greater:

data-sort-type="number"			width=200	Location	width=200	Operator		class=unsortable	Comments
Rosse Six Foot Telescope (reconstructed) [1]	72sigfig=3NaNsigfig=3	Newtonian reflector	Birr, Leinster, Ireland		1999	Largest optical telescope in Ireland
38-inch Congo Schmidt [2]	38sigfig=3NaNsigfig=3	Reflector	Herstmonceux, East Sussex, England		1960	Largest optical telescope in UK, but never used due to flawed optics
James Gregory Telescope[3]	37sigfig=3NaNsigfig=3	Cassegrain reflector	St Andrews, Fife, Scotland		1962	Largest operational optical telescope in the UK
Cambridge 36-Inch telescope[4]	36sigfig=3NaNsigfig=3	Reflector	Cambridge, Cambridgeshire, England		1955	Largest optical telescope still in use in England
36-inch Yapp telescope[5]	36sigfig=3NaNsigfig=3	Reflector	Herstmonceux, East Sussex, England	The Observatory Science Centre	1932
Edinburgh 36-inch telescope [6]	36sigfig=3NaNsigfig=3	Reflector	Edinburgh, Scotland		1930	No longer operational
34-inch Hewitt Camera [7]	34sigfig=3NaNsigfig=3	Reflector	Herstmonceux, East Sussex, England	The Observatory Science Centre	1950s
Perren Telescope [8]	31.5sigfig=3NaNsigfig=3	Ritchey–Chrétien reflector	Mill Hill, London, England		2019
Thomson/Regan/Owen Reflector	30sigfig=3NaNsigfig=3	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]	30sigfig=3NaNsigfig=3	Refractor	Hanwell, Oxfordshire, England	Hanwell Community Observatory	1999	Largest refractor in the British Isles
30" Dobsonian [10]	30sigfig=3NaNsigfig=3	Reflector	Todmorden, West Yorkshire, England	The Astronomy Centre	1986
Thompson 30-inch Reflector [11]	30sigfig=3NaNsigfig=3	Reflector	Herstmonceux, East Sussex, England	The Observatory Science Centre	1896
Greenwich 28 inch refractor[12]	28sigfig=3NaNsigfig=3	Refractor	Greenwich, London, England		1893
Moses Holden Telescope [13]	27.6sigfig=3NaNsigfig=3	Reflector	Preston, Lancashire, England		2015
Thompson 26-inch Refractor [14]	26sigfig=3NaNsigfig=3	Refractor	Herstmonceux, East Sussex, England	The Observatory Science Centre	1897
24 / 17" Schmidt Camera [15]	24sigfig=3NaNsigfig=3	Reflector	Knighton, Powys, Wales	The Spaceguard Centre	1950	Largest optical telescope in Wales
Thornton Telescope [16]	24sigfig=3NaNsigfig=3	Reflector	Keele, Staffordshire, England		1975
24" Telescope [17]	24sigfig=3NaNsigfig=3	Reflector	Bayfordbury, Hertfordshire, England		2021

Historical

• Isaac Newton Telescope at Herstmonceux, 98 inches (1965-1979)
• Leviathan of Parsonstown, 1842- ~1890
• 3-foot telescope at Parsons
• RGO telescopes at different points in its history^[18]
  • 38-inch Hargreaves Reflector (1960)
  • Yapp 36-inch Reflector (1932)
  • 30-inch Steavenson Reflector (1939)
  • 28-inch Refractor (1893)
  • Thompson Telescope with a 26-inch refractor and 30-inch reflector on one mounting (1896)
  • Lassell 2-foot Reflector (1845)
  • Isaac Roberts 20-inch reflector (1885)
  • Western Equatorial (c.1824)
  • 13-inch Astrographic Refractor (1890)
  • Merz 12.8-inch Visual Refractor (1859-1893) (this was replaced by the 28 inch Grubb in the onion dome)
  • Thomson 9-inch Photographic Refractor (c.1888)
  • Sheepshanks refractor 6.7-inch (1838) (aka Sheepshanks Equatorial)
  • 6-inch Franklin Adams Camera (1898)
  • Shuckburgh telescope a 4.1-inch aperture Refractor (1791)
• At the Observatory Science Center (at Herstmonceux)^[19]
  • Hargreaves 38 inch Congo Schmidt
  • Yapp 36 Inch reflector
  • Thompson 30 inch reflector
  • Thompson 26 inch reflector
• Markree Observatory 13.3" Cauchoix (the largest refractor of the early 1830s)
• A.A. Commons reflectors (later reworked into Crossley and Harvard telescopes)
• Lassel's reflector, this 24 inch metal mirror telescope was used to discover the moons Triton and Hyperion.^[20]
• Newton's reflector
• 40-foot telescope (England)
• Armagh Observatory 15-inch Grubb reflecting telescope.^[21] Specula metal mirror mounted on an equatorial, with clockwork-drive.
• Bedford Observatory Tully 5.9 inch refractor (8.5 feet focal length); Dollond mount with Sheepshanks clockwork drive.^[22]
• Cambridge Observatory 36 inch (3 feet = 91.44 cm) aperture reflector

Observations

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.

See also

• Lists of telescopes
• List of telescopes of Australia
• David Dunlap Observatory (Largest telescope of the British Empire in the 1930s)

External links

• The 98 inch (249 cm) mirror glass of original INT

Notes and References

1. Web site: The Great Telescope at Birr Castle Birr Castle, Gardens & Science Centre Ireland.
2. Web site: The 38-inch Congo Schmidt.
3. Web site: JGT – Observatory.
4. Web site: 36-Inch Telescope . Institute of Astronomy . University of Cambridge.
5. Web site: The 36-inch Yapp Reflector.
6. Web site: The Royal observatory, Edinburgh.
7. Web site: The 34-inch Hewitt Camera.
8. Web site: Perren Telescope. 29 October 2018.
9. Web site: John Wall refractor Hanwell Community Observatory.
10. Web site: The rebuilt 30" Dobsonian.
11. Web site: Dome A - the Thompson 30-inch reflecting telescope.
12. Wright . D. C. . The 28-inch Refractor at Greenwich - a History of Two Telescopes . . 31 . 4 . 551–566 . . 1990 . 1990QJRAS..31..551W .
13. Web site: Alston Observatory – Jeremiah Horrocks Institute.
14. Web site: Dome e - the Thompson 26-inch refracting telescope.
15. Web site: Project DRAX in Detail the Spaceguard Centre.
16. Web site: 1970s, Keele University.
17. Web site: Telescopes.
18. Web site: Telescopes.
19. Web site: Observatory Science Centre at Herstmonceux. www.millseyspages.com. 2019-10-27.
20. Web site: The Royal Observatory Greenwich - where east meets west: Telescope: The Lassell 2-foot Reflector (1847). www.royalobservatorygreenwich.org. 2019-11-28.
21. Web site: The 15-inch Equatorial Reflector by Thomas Grubb at Armagh Observatory. Butler. C.J..
22. 1949PA.....57...74K Page 74. adsabs.harvard.edu. 1949PA.....57...74K. 2019-10-31.
23. Book: New Scientist. 1983-08-04. Reed Business Information. en.