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; see sext ¹, -ant

Explanation

A sextant is a tool for measuring the angles between heavenly bodies — the kind found in outer space. Used as a navigational tool out at sea, it helps determine a ship's longitude and latitude. There is nothing sexy about a sextant, unless you're a sailor. Even then, in today's world of sophisticated instrumentation, it's considered quaint and old-fashioned. The noun sextant dates back to the late 16th century, from the Latin word sextans, meaning "sixth part." The sextant uses a graduated arc of 60° (there's the six reference) for measuring the altitude of the planets and stars.

Example Sentences

The Macneil Sextant has a curved reflector that collects and potently focuses infra-red rays on a thermocouple, two pieces of metal which when heated even one-millionth of 1° give off a tiny flow of electricity.

From Time Magazine Archive

This technique has been used by Manhattan's Sextant Inc. to make one of the most expensive and unusual documentary TV shows ever done.

From Time Magazine Archive

Hagner is also the inventor of the Hagner Position Finder and the Hagner Sextant, which are standard equipment in the U.S.

From Time Magazine Archive

The clouds last night prevented my taking any lunar observations this day I took Equal Altitudes of the 0 with Sextant.

From The Journals of Lewis and Clark, 1804-1806 by Lewis, Meriwether

So when the soldiers marched out north from Luca about six miles, they could halt and smile at each other, and say 'At Sextant... that's all right.

From The Path to Rome by Belloc, Hilaire