The eighth part of a circle; an arc of 45 degrees.
The position or aspect of a heavenly body, as the moon or a planet, when half way between conjunction, or opposition, and quadrature, or distant from another body 45 degrees.
An instrument for measuring angles (generally called a quadrant), having an arc which measures up to 9O°, but being itself the eighth part of a circle. Cf. Sextant.
Device made from one eighth of a circle, used for measuring angular distance.
The backstaff was an early navigational instrument used to gauge latitude at sea. It was replaced by a more accurate device called the octant. The octant was replaced by an even more accurate instrument, the sextant, which is still being used today. Note: Latitude is the distance north or south of the equator, which is measured on a map or globe in degrees along a meridian
Navigational instrument which measures the angle of the sun above the horizon. It was invented by John Hadley in 1731, but was superseded by the more accurate sextant in the late 18thC.
A navigational tool used for measuring angles, based on astronomy.
a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration
a portable instrument that uses a small mirror to bring two images together--those of the sun and the horizon, for instance--to determine latitude at sea by observing the altitude of celestial bodies
Navigation instrument measuring solar and stellar heights. Photos.
an instrument shaped like an eighth of a circle, marked with lines for measuring degrees, used in astronomy, navigation and surveying
the eighth part of a circle or an instrument measuring up to 45 degrees.
An instrument for measuring angles, with a graduated arc of 45°.
Octant is a measuring instrument similar to a sextant. Its scale is 1/8 of a circle (45°) rather than the sextant's 1/6.
