What a Sextant Is?

John Campbell invented the sextant in 1757. It measures both longitude and latitude by determining the angle of the sun, moon, or stars compared to the horizon. The angle and the time when it is measured are used to calculate a position line on a nautical chart. The word sextant comes from the Latin word meaning "one sixth." The scale of a sextant has a length of 1/6th of a full circle, or 60°. The sextant is still used today as a back-up navigational tool for boats since it doesn’t require electricity.