from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A navigational instrument containing a graduated 60-degree arc, used for measuring the altitudes of celestial bodies to determine latitude and longitude.
- n. See Sextans.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A navigational device for deriving angular distances between objects so as to determine latitude and longitude.
- n. One sixth of a circle or disc; a sector with an angle of 60°.
from the GNU version of the Collaborative International Dictionary of English
- n. The sixth part of a circle.
- n. An instrument for measuring angular distances between objects, -- used esp. at sea, for ascertaining the latitude and longitude. It is constructed on the same optical principle as Hadley's quadrant, but usually of metal, with a nicer graduation, telescopic sight, and its arc the sixth, and sometimes the third, part of a circle. See Quadrant.
- n. The constellation Sextans.
from The Century Dictionary and Cyclopedia
- n. In mathematics, the sixth part of a circle. Hence An important instrument of navigation and surveying, for measuring the angular distance of two stars or other objects, or the altitude of a star above the horizon, the two images being brought into coincidence by reflection from the transmitting horizon-glass, lettered b in the figure.
- n. [capitalized] Same as Sextans, 2.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a measuring instrument for measuring the angular distance between celestial objects; resembles an octant
- n. a unit of angular distance equal to 60 degrees
I had to confess that I was not a navigator, that I had never looked through a sextant in my life, and that I doubted if I could tell a sextant from a nautical almanac.
A sextant is a navigational instrument that measures the altitudes of celestial bodies.
Determining this in the 19th century most commonly involved the use of an optical device known as a sextant to measure the position of a celestial object (such as the sun) at a specific time (usually noon).
The sextant is a powerful optical instrument, magnifying everything it sees twenty-eight times, but the price it pays for this magnification is a very narrow field of view, only 1.8 degrees wide corresponding to 0.6 miles on the ground, so that it is almost like looking down a gun barrel.
If the object to be assaulted is a large one, a practical man can, by the exercise of moderate judgment after two or three fires, throw the bombs near the work; but, at the same time, the sextant is the more certain means for determining the true distance, and the
In another class-room, we find a staff commander teaching a class how to use the sextant, which is the sailor's most useful instrument for finding his place at sea, from sun and stars; or he may be teaching them how to use a chart or to draw a chart themselves.
At that instant the sun is on your meridian, it is noon at the ship, and the angle you read from your sextant is the meridian altitude of the sun.
The sextant is the one most in use and so will be described first.
The sextant, which is the instrument universally used at sea, was gradually evolved from similar instruments used from the earliest times.
So you understand, what with the "dead reckoning," and the curious instruments I told you of -- one of them is called a sextant -- the captain can take his ship right across the pathless ocean, just as easily as a coachman does his coach along a high-road.