sextant
What is the opposite of sextant? Here is what we hold, with its meaning and related words.
Noun — A navigational instrument with a graduated arc and mirrors, used to measure the angle between a celestial body and the horizon in order to work out latitude and position at sea.
How to use sextant
The word patterns that sound natural to a native speaker.
take a sight with a sextant
a marine sextant
sextant altitude
shoot the sun
Neutral; nautical and historical contexts.
Etymology
From Latin sextans 'a sixth part', because the instrument's graduated arc spans a sixth of a circle, that is sixty degrees.
Full origin of sextant →Frequently asked questions
How does a sextant work?
You look at the horizon through a half-silvered mirror and swing an arm carrying a second mirror until the reflected image of the sun or a star sits exactly on that horizon line. The angle read off the arc, combined with the exact time and published tables, gives your position.
What is the difference between a sextant and an astrolabe?
An astrolabe is an older instrument, held hanging vertically, that measures a body's altitude against a fixed scale and is hard to use on a moving deck. A sextant uses mirrors to bring the body and the horizon into the same view, so it stays accurate on a pitching ship and is far more precise.
Are sextants still used?
Yes, though rarely as the primary method. Merchant and naval officers still train in celestial navigation as a backup for GPS failure or jamming, and ocean sailors carry a sextant for the same reason.
