Sextant, instrument for determining the angle between the horizon and a celestial body such as the Sun, the Moon, or a star, used in celestial navigation

to determine latitude and longitude. The device consists of an arc of a circle, marked off in degrees, and a movable radial arm pivoted at the centre of the circle.

Is the sextant used today?

It's a real historic instrument that is still in use today. Even today big ships are all required to carry working sextants and the navigating officers have regular routines to keep themselves familiar with making it work.

When was the sextant used?

The principle of the instrument was first implemented around 1731 by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but it was also found later in the unpublished writings of Isaac Newton (1643–1727). In 1922, it was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho.