1. sextant - Noun
2. Sextant - Proper noun
The sixth part of a circle.
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.
The constellation Sextans.
Source: Webster's dictionaryAfter a week of travel a sextant observation indicated that they were averaging nine nautical miles a day, (17 km; 10 mi), putting them ahead of schedule. Source: Internet
Advantages Like the Davis quadrant (also called backstaff), the sextant allows celestial objects to be measured relative to the horizon, rather than relative to the instrument. Source: Internet
A nautical almanac and a marine chronometer are used to compute the subpoint on earth a celestial body is over, and a sextant is used to measure the body's angular height above the horizon. Source: Internet
Historically, observatories were as simple as containing an astronomical sextant (for measuring the distance between stars ) or Stonehenge (which has some alignments on astronomical phenomena). Source: Internet
A sextant does not require a completely steady aim, because it measures a relative angle. Source: Internet
;Collimation error:This is when the telescope or monocular is not parallel to the plane of the sextant. Source: Internet