Nocturnal (front)

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A nocturnal shows the local time at night, by measuring the rotation of the constellations of the Great Bear and the Little Bear around the Pole Star. This boxwood example was made in England around 1740. The photograph shows the front of the instrument.

The nocturnal consists of three parts with a brass central pivot. There is a long index arm and a middle piece with two scales and two pointers marked 'GB' and 'LB'. The main part has a calendrical scale and is marked above the handle 'BOTH BEARS'.

This instrument was probably used mainly by navigators, and the skilled practitioner could expect to be accurate within 15 minutes. The instrument was introduced in the 16th century and remained popular until the mid 18th century.

Record details

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• Online ID: 000-100-102-817-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1984.60
• Date: Around 1740
  c. 1740
  
• Material: Boxwood
  Nocturnal
  
• Dimensions:
• What: Nocturnal
  
• Subject:
• Who:
• Where: England
  
• Event:
• Description: Boxwood nocturnal of English manufacture, c. 1740
  
• References:
  • For a description of how the nocturnal works, see Bennett, J.A., The Divided Circle: A history of instruments for astronomy, navigation and surveying. Oxford: 1987, pp 77-9 
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