Craig telescope

Craig telescope
Location(s) Wandsworth Common, London,
Wavelength Visible light
Built 1852
First light 1852
Telescope style Achromatic Refractor
Diameter 2 feet[1]
Focal length 76-83 feet[1]
Mounting Gravatt alt/azimuth

The Craig telescope was the largest refracting telescope (a telescope with a lens) in the world from 1852 to 1857, erected near London, England.[2][3] It was a great refractor, a large refracting telescope with an achromatic doublet with an aperture of 61 cm (2 feet (24 inches)) and that was completed in 1852 in Wandsworth Common and dismantled around 1857 (although the brick tower probably survived until 1870).[2][3] Its namesake, the Rev. John Craig, spent a small fortune to produce a uniquely designed telescope with nearly double the aperture of the next largest refracting telescopes, making it the largest refracting telescope in the World for the better part of a decade.[2][3] However, it had problem with its lens figuring starting from its first light in the summer of 1852.[2][4] It soon fell into disuse as that same year Craig lost his only son, then his wife in 1854, and lost his brother and was put in jail for 6 weeks in 1856.[2]

Craig did not have the lens re-figured and the telescope struggled to achieve his modest goals, which included observations of Earth's Moon and Saturn.[2] It was eventually demolished and Craig moved on to other projects, including opening one of the first indoor skating rinks.[2]

The doublet was made with flint glass by Chance Brothers and a plate glass by Thames Plate Glass Company.[3] The mounting was designed by William Gravatt, and featured a 19.5 meter tall brick tower with a 24.5 m long cigar shaped telescope tube (built by Messrs Rennie) slung from the side.[3][5]

The next largest refractors were two 15 inch (38 cm) refractors built by Merz and Mahler of Münich (Joseph Fraunhofer's firm), one at Pulkovo Observatory in Europe and one at Harvard College Observatory in America. The largest telescope at the time was in Ireland, a 6 foot (183 cm) aperture metal mirror by William Parsons, 3rd Earl of Rosse. (see "Leviathan of Parsonstown")

See also

References

  1. 1 2 ANNUAL OF SCIENTIFIC DISCOVERY:1854, Page 156 (Google Books 2010)
  2. 1 2 3 4 5 6 7 The Online Museum of the Craig Telescope (www.craig-telescope.co.uk)
  3. 1 2 3 4 5 New Scientist: Dec 2, 1982 "The Monster Telescope at Wandworth"
  4. ↑ The Mechanics' magazine, museum, register, journal, and gazette, Volume 57, Page 354. (Google Books 2010)
  5. ↑ "The geography of the heavens: and class-book of astronomy: accompanied by a ..." By Elijah Hinsdale Burritt, Henry Whitall, Page 324. Google Books 2010

Further reading

External links

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