mid-18th century

Australian National Maritime Museum

Australian National Maritime Museum

This Davis backstaff was designed to measure the altitude of the sun and determine latitude. Its innovative design allowed the user to measure the height of the sun without looking directly at it, saving the eyesight of many navigators! It was constructed from lignum vitae and boxwood, with scales divided over one side and an inset of ivory plate. This version of the backstaff could measure the sun's altitude up to 65 degrees.

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  • Title: Backstaff
  • Date: mid-18th century
  • Type: Backstaff
  • Significance: The Davis backstaff represents equipment used for maritime navigation and exploration between the 16th and 18th centuries. It was the technological link between the astrolabe and the development of the reflecting quadrant.
  • See institution's online collections: http://www.anmm.gov.au/collections
  • Medium: Lignum vitae, boxwood, ivory
  • Dimensions: 650 x 355 mm, 0.62 kg
  • Credit line: ANMM Collection