A sextant is an instrument used in navigation. Anyone taking the coastal skipper exam today is required to be able to use a sextant in case the GPS (Global Positioning System) does not work because of a dead battery or other reasons. The Fram Museum has two large sextants with wooden cases. The sextant in the photograph has six different lenses which admit more or less light from the sun, a star, a planet or the moon. “Sextant” comes from Latin and means ‘one sixth’. The instrument is used for measuring angles, and has a graduated arc of 60°, which is 1/6 of a full circle of 360°. The sextant was used to find exact positions on sea or land by measuring the angle between a celestial body (eg the sun or a star) and the horizon, and it was an indispensible aid also on the long sledge expeditions towards the North and South Poles.