octant

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octant

[′äk·tənt]
(mathematics)
One of the eight regions into which three-dimensional Euclidean space is divided by the coordinate planes of a Cartesian coordinate system.
A unit of plane angle equal to 45° or π/8 radians.
(navigation)
A double-reflecting instrument used primarily for measuring altitudes of celestial bodies from a moving ship or airplane; has a range of 90°, and while a sextant has the capability up to 120°, the common practice applies the name sextant to both types of instruments.

Octant

[′äk·tənt]
(astronomy)

Octant

 

a goniometric instrument whose main component is an arc that forms one-eighth of a circle and is divided into degrees and fractions of a degree. Instruments similar in design to sextants are usually called octants. Octants have almost completely fallen out of use.

octant

octant
octant
When an aircraft accelerates, inertia causes the otolith membrane in a pilots' otolith organ to move. This results in the sensation of climbing and might cause the pilot to push the stick forward and dive. The reverse would occur in case of deceleration.
An instrument similar to a bubble sextant but constructed with its arc graduated in degrees for an eighth of a circle. Frequently called a sextant. An octant can measure angles up to 90°.