The angle between the two objects is then read off the scale. What makes a sextant so useful in navigation is its accuracy. It can measure an angle with precision to the nearest ten seconds.

Discover some of the incredible tools, from astrolabes to sextants, that ancient sailors ... to architecture to farming and, ...

The prism and drum are geared to circular scales ... With my sextant, I measured the altitude of the star Sirius to be 22°11’. I then went to The Nautical Almanac, where a number of tables ...

Polished brass sextant, diamond-pattern frame type, with polished brass limb wooden handle and threaded hole for stand with shaped mahogany case by Troughton and Simms, Fleet St., City of London, ...