sextant

American  

[sek-stuhnt] / ˈsɛk stənt /

noun

1. an astronomical instrument used to determine latitude and longitude at sea by measuring angular distances, especially the altitudes of sun, moon, and stars.

2. Astronomy. Sextant, the constellation Sextans.

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sextant British  

/ ˈsɛkstənt /

noun

1. an optical instrument used in navigation and consisting of a telescope through which a sighting of a heavenly body is taken, with protractors for determining its angular distance above the horizon or from another heavenly body

2. a sixth part of a circle having an arc which subtends an angle of 60°

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sextant Scientific  

/ sĕk′stənt /

1. An instrument containing a graduated 60° arc and a movable pivoted arm corresponding to the radius of the arc's circle, used in celestial navigation to measure the altitude of a celestial body in order to determine the observer's latitude and longitude. A horizontally mounted telescope and two small mirrors are arranged so that the observer can, by moving the pivoted arm, sight the horizon and the reflected image of the celestial body in the same line, giving a reading along the arc that is used to look up the observer's position in a published table.

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Etymology

Origin of sextant

First recorded in 1590–1600; from Latin sextant- (stem of sextāns ) sixth part of a unit; sext ¹, -ant

Example Sentences

Give him a sextant and a glimpse of the stars, and there was no chance of getting lost.

From Literature

“No bird to the north,” Alexander announced, checking the sextant.

From Literature

“No, we do not need a sextant—nor an abacus, Cassiopeia, please put that back.”

From Literature

Expecting this, the pilot was prepared to navigate as sea captains had done for centuries, using star charts and a sextant.

From Literature

As navigator, Lovell took with him a sextant to take star readings - in case the computers failed and they had to find their own way home.

From BBC