Jesse Ramsden

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Jesse Ramsden

Jesse Ramsden (* 6. October 1735 in Halifax in the county of Yorkshire , † 5. November 1800 in Brighton , Sussex ) was an English optician and manufacturer of mathematical and optical instruments.

Live and act

He learned copperplate engraving , but then practiced - as the son-in-law of the famous optician John Dollond  - with skill in the art of improving optical and astronomical instruments. He achieved significant improvements with the theodolite , the pyrometer and the barometer used for height measurement , as well as with the quadrants and sextants for the court astronomer Edmond Halley .

Ramsden's most important invention is the circle dividing machine for the production of precise graduated circles , described in Description of an engine for dividing mathematical instruments (London 1777). He was also known for his high quality telescopes and wall quadrants . Its Ramsden eyepiece combines extensive color purity with suitability for a crosshair eyepiece .

Because of his many successes, Ramsden was inducted into the Royal Society in 1786 - an honor which only a few outstanding artisans in London received. The Royal Society of Edinburgh also accepted him as a member. In 1793 he became an honorary member of the Russian Academy of Sciences in Saint Petersburg .

Italian astronomer Giuseppe Piazzi used 1801 in the discovery of dwarf planet (1), Ceres on Observatory of Palermo the fabricated of Ramsden wall quadrant.

The lunar crater Ramsden and the asteroid (8001) Ramsden are named after Jesse Ramsden.


  • Anita McConnell: Jesse Ramsden (1735-1800). London's leading scientific instrument maker. Ashgate Publ., 2007.
  • Ralf Kern: Scientific instruments in their time. Walther König, Cologne 2010, ISBN 978-3-86560-772-0 .
  • Ramsden, Jesse . In: Encyclopædia Britannica . 11th edition. tape 22 : Poll - Reeves . London 1911 (English, full text [ Wikisource ]).

Web links

Commons : Jesse Ramsden  - collection of images, videos and audio files

Individual evidence

  1. Ralf Kern: Scientific instruments in their time, Volume 3: Striving for accuracy in time and space. Cologne 2010, p. 350.
  2. ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF file) Royal Society of Edinburgh, accessed April 1, 2020 .
  3. ^ Foreign members of the Russian Academy of Sciences since 1724. Jesse Ramsden. Russian Academy of Sciences, accessed October 18, 2015 .