alb4604541

18th century illustration showing a backstaff or English quadrant. 1776. The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back (hence the name) and saw the shadow cast by the upper vane on a horizon vane. It was invented by the English navigator John Davis who described it in his book Seaman's Secrets in 1594

18th century illustration showing a backstaff or English quadrant. 1776. The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back (hence the name) and saw the shadow cast by the upper vane on a horizon vane. It was invented by the English navigator John Davis who described it in his book Seaman's Secrets in 1594.
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Caption:
18th century illustration showing a backstaff or English quadrant. 1776. The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back (hence the name) and saw the shadow cast by the upper vane on a horizon vane. It was invented by the English navigator John Davis who described it in his book Seaman's Secrets in 1594
Credit:
Album / Universal Images Group / Universal History Archive
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Image size:
4488 x 4673 px | 60.0 MB
Print size:
38.0 x 39.6 cm | 15.0 x 15.6 in (300 dpi)