Octant (detail)

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An octant is a navigational instrument used for measuring angles necessary for determining a ship's position at sea. This is a detail from an ebony octant made in England around 1755.

The detail shows the arc and, at the top, an ivory plate inscribed with the date, 1755, and the owner's name, 'George Harris'. The name has been obliterated, probably when the octant changed hands.

The earlier mahogany-framed octants were gradually superseded by smaller ebony-framed instruments, with brass radial arms. This example also has an inlaid ivory scale with diagonal divisions, which survived until about 1770.

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• Online ID: 000-190-002-050-C
• Image Rights Holder: National Museums Scotland
• Project: National Museums Scotland
  Project description   View all records in project
• Ref: National Museums Scotland  T.1876.11
• Date: 1755
  
• Material: Octant
  
• Dimensions:
• What: Octant
  
• Subject:
• Who: George Harris ? (Maker)
  
• Where:
• Event:
• Description: Octant, an instrument for measuring the angular distances of objects by reflection, dated 1755
  
• References:
  • Bennett, J.A. The Divided Circle: A history of instruments for astronomy, navigation and surveying. Oxford: 1987, pp 132-4 
• Translations:
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