Ramsden's three foot geodetic theodolite

1792 in England and London
Jesse Ramsden

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Theodolite by Ramsden, used on the Principle Triangulation of Great Britain and Ireland, 1792. With parts.

This theodolite is the oldest surviving of its size and was used on the Principal Triangulation of Great Britain and Ireland from 1792 to the early 19th century. It was used to measure both vertical and horizontal angles to a high degree of accuracy. This helped to produce the network of reference points underpinning the Ordnance Survey maps of the United Kingdom.

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Object Number:
geodetic theodolite
  • furnishing and equipment
  • measuring device - instrument
  • theodolite
Ordnance Survey
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