This elegant marine instrument, which is actually a reproduction of a mid-18th century octant, allows sailors to determine its position in the sea. By semi-accurately measuring the height of the stars or the sun, navigators have found their geographical latitude. Its creation is the subject of debate. It was independently demonstrated in the same year (1731) by J. Hadley (England) and T. Godfrey (USA). Over time, the wooden frame of the sextant (1757) was replaced by metal. It is still in use today.