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[bak-sahyt] /ˈbækˌsaɪt/
noun, Surveying
a sight on a previously occupied instrument station.
(in leveling) the reading on a rod that is held on a point of known elevation, used in computing the elevation of the instrument.
Origin of backsight
1840-50; back2 + sight Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for backsight
  • Simply add the backsight reading to the elevation of the bench mark to get the height of the instrument above gage datum.
  • At the conclusion of each set up, the direction to the backsight should be reobserved.
  • Requires observing backsight multiple times for large number of foresights.
  • backsight requirements are unaffected by the number of foresights.
  • Set zero in the instrument and backsight a point on tangent or foresight a point on semi-tangent.
  • The direction of each foresight is measured in relationship to the backsight.
  • After taking a backsight, the deflection angle for the instrument station is turned.
  • Usually, the instrument reader will have more confidence in either the foresight or backsight.
  • The instrument is occupying one point, with tripods occupying the backsight and foresight.
  • All angles are turned in a clockwise direction from the backsight.
British Dictionary definitions for backsight


the sight of a rifle nearer the stock
(surveying) a reading taken looking backwards to a previously occupied station Compare foresight (sense 4)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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