The Collaborative International Dictionary
Backstaff \Back"staff`\, n. An instrument formerly used for taking the altitude of the heavenly bodies, but now superseded by the quadrant and sextant; -- so called because the observer turned his back to the body observed.
Wiktionary
n. (context nautical English) An early navigational instrument for measuring the altitude of the sun and hence calculating latitude
Wikipedia
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 observed 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.
Usage examples of "backstaff".
He lowered the backstaff with aching arms and shoulders, and hastily scribbled the reading on the traverse slate.
On the second finger of his right hand he wore a narrow gold ring, engraved with a compass and a backstaff, the tools of the navigator, and above these a crowned lion.
Chief among these were a chart and compass, and a backstaff if they could find one.
Hal laid aside these precious documents and took up the backstaff Sukeena had found.
A dozen pieces of eight, several items of silver dinner plate, a backstaff and a dozen ten-inch ship spikes.
It is difficult enough to use a backstaff, let alone a telescope, on a moving ship, especially on a rough swell such as one finds in the Pacific.
Charee has been found guilty of murdering the backstaffer, and the cooper Kharl has been found guilty of failing to protect the defenseless under his care and of resisting lawful authority.
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that would moderate his zeal, and while the bosun and his mates were laying out the intricacies of their lines, fore and aft, Jack Aubrey stood .
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that would moderate his zeal, and while the bosun and his mates were laying out the intricacies of their lines, fore and aft, Jack Aubrey .
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that would moderate his zeal, and while the bosun and his mates were laying out the intricacies of their lines, fore and aft, Jack Aubrey stood leaning on the elegant .
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that would .
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that .
The dear topgallant breeze had chased away any hint of mist the night might have left and this was a light-filled day with a deep blue sky from horizon to horizon - a transparent air that allowed small details to be seen a great way off, and although when the sun reached his zenith - the exact height to be measured by every soul aboard who could command a sextant, quadrant or backstaff - his warmth might be troublesome, but euphroes were already at hand for the awnings that would moderate his zeal, and while the .