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The Method of using a Backstaff
Document Type: Photo/Image
Geographic Location: London, England
ID Number: Backstaff_Demo
Keywords: Navigation
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Description:
This drawing shows the use of the backstaff. It shows how the observer looks away from the sun and lines up the shadow of a vane, while sighting the horizon to find the altitude of the sun. Invented by John Davis, this drawing is from John Davis's Seaman's Secrets, published in 1595.
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