Telescope

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This telescope was made around 1780, and retailed by the younger George Adams (1750-1795), a scientific instrument maker based in London.

The 3-inch refracting telescope (the size of the diameter of the objective lens) is an example of a London instrument supplier using the new form of objective lens which corrected chromatic aberration (colour fringes in the images) by using a combination of crown and flint glass, after the lapse in 1772 of the patent obtained by the Dollonds. The instrument pivots on a cylindrical brass pillar, at the base of which is a spring-loaded lever operating the fine adjustment: by turning the wooden handle, this is moved. The instrument has a tripod and fitted case (neither shown), but lacks accessories.

Despite Issac Newton's optical researches, which actively hindered the development of the refracting telescope, some investigations into improving the image were made in the early 18th century. Although John Dollond (1706-61) did important work in this area, and was persuaded by his son Peter to obtain a patent, this was disputed - although not very successfully - by other London opticians. In 1766 and 1771 George Adams (the Elder), who died in 1772, advertised telescopes 'with 5 or 6 glasses' at a guinea (£1-05) a foot.

Record details

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• Online ID: 000-100-104-231-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1967.17
• Date: Around 1780
  c. 1780
  
• Material: Brass telescope / wooden tripod / wooden box. Inscription: G * ADAMS, LONDON
  Telescope / tripod / box
  
• Dimensions: Box 4.75" H x 44.50" L x 9.00" W
  
• What: Telescope / tripod / box
  
• Subject: 3. ASTRONOMY, Refracting telescopes (Departmental Classification)
  22. PHYSICS, Light (Departmental Classification)
  
• Who: G. Adams, London (Maker)
  
• Where: England, London
  
• Event:
• Description: Telescope with tripod, in wooden box, by G. Adams, London, c. 1780
  
• References:
  • For George Adams (father and son), see Clifton, Gloria, Directory of British Scientific Instrument Makers 1550-1851. London: 1995, pp 2-3 
  • For the invention of the achromatic telescope, see King, Henry C., The History of the Telescope. New York: 1955, chapter 8, pp 144-75 
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