sextant
/ˈsɛkst(ə)nt
/noun
An instrument with a graduated arc of 60° and a sighting mechanism, used for measuring the angular distances between objects and especially for taking altitudes in navigation and surveying.Later, celestial navigation using sextants and fairly accurate clocks enabled absolute positioning, but the sailors had to refer back to dead reckoning on days with poor weather conditions....
- Selecting five of the hardiest men, he took a single boat on a journey of 800 miles, across a raging sea, with a sextant the only navigation tool, to the island of South Georgia.
- Having begun my navigation career with star shots on sextants and theodolites and sun-compasses during the day, I appreciated the technical brilliance of the GPS (the US Global Positioning System).
Origin
Late 16th century (denoting the sixth part of a circle): from Latin sextans, sextant- 'sixth part', from sextus 'sixth'.