History and Instruments

How does a sextant help navigators?

In 1730, the sextant was invented independently by two men, John Hadley and Thomas Godfrey. Using a telescope, two mirrors, the horizon, and the sun (or another celestial body), the sextant measures the angle between the horizon and the celestial body. With this measurement, navigators could determine their latitude while at sea.

A “compass rose” is the ornamentation surrounding a compass dial that is divided into the four cardinal directions, and then into further divisions.

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