octant
Quick Summary
An octant is an instrument used in navigation to measure the altitude of celestial bodies from a moving ship or aircraft. It was an early form of the modern sextant.12
How it Works
The octant, with an arc of 45 degrees, was used to calculate latitude. Navigators would use it to measure the angle between the horizon and a celestial body, such as the polestar or the Sun. This measurement, combined with astronomical data and the time, allowed them to determine their position. The octant was an improvement over earlier instruments like the astrolabe and quadrant, and it remained in use until the 18th century when it was largely replaced by the sextant.32
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navigationLatitude measurementsā¦even after 1731 when the octant (an early form of the modern sextant) was demonstrated independently by John Hadley of England (see photograph) and Thomas Godfrey of Philadelphia. In the octant and the sextant, two mirrorsāone fixed, the other movableābring the image of the Sun into coincidence with the horizon.ā¦
Read Moreā¦even after 1731 when the octant (an early form of the modern sextant) was demonstrated independently by John Hadley of England (see photograph) and Thomas Godfrey of Philadelphia. In the octant and the sextant, two mirrorsāone fixed, the other movableābring the image of the Sun into coincidence with the horizon.ā¦
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history of technologyTransport and communicationsā¦improved by conversion to the octant, using mirrors to align the image of a star with the horizon and to measure its angle more accurately: with further refinements the modern sextant evolved. Even more significant was the ingenuity shown by scientists and instrument makers in the construction of a clockā¦
Read Moreā¦improved by conversion to the octant, using mirrors to align the image of a star with the horizon and to measure its angle more accurately: with further refinements the modern sextant evolved. Even more significant was the ingenuity shown by scientists and instrument makers in the construction of a clockā¦
Read More