Quadrant (instrument) - Wikipedia
A quadrant is an instrument used to measure angles up to 90°. Different versions of this instrument could be used to calculate various readings, such as longitude , latitude , and time of day . Its earliest recorded usage was in ancient India in …
Quadrant | nautical instrument | Britannica
…of Philadelphia, Hadley invented a quadrant (actually a double-reflecting octant) for measuring the altitude of the Sun or a star above the horizon to find geographic position at sea. His double-reflecting principle made accurate determinations of location much easier. Hadley also fixed a spirit level to the instrument so that… Read More
Quadrant - U.S. National Park Service
2022年1月5日 · First used in the fifteenth century, the quadrant was the most popular navigational tool of the mid-eighteenth century. In order to determine his ship's position at sea, a sailor would use this instrument to measure the angle of the sun over the horizon at noon, and then use that measurement to calculate his vessel’s latitude.
Quadrant - Ages of Exploration - Mariners' Museum and Park
It was simply a device for measuring the angular height of a star or the sun. Surveyors could use it to measure the height of a building or a mountain. It was even used to help aim a cannon to hit an enemy fortress. For the sailor, it was first used to measure the height of Polaris, the Pole star.
GA4 Tracking Code - Harvard Collection of Historical Scientific Instruments
The instrument could measure angles up to 90° in an arc of only 45° and so was known by two names—Hadley’s quadrant or an octant. This quadrant is a prototype tested at sea by George Hadley, brother of John, and is the earliest example known to survive.
Quadrant - SpringerLink
The quadrant is an instrument which was used for measuring angles and for making astronomical calculations. Apart from those for the accurate observation of altitude, known to us almost entirely from written descriptions, the quadrants of the Arabic Middle Ages were portable.
Quadrant (instrument) - Infogalactic: the planetary knowledge core
A quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.
Museo Galileo - In depth - Quadrant
Astronomical instrument with engraved markings showing the projection of the celestial coordinates. The markings are directly derived from those of the astrolabe, but are reduced and repositioned to fit inside the quarter-circle. In essence, this is an astrolabe folded twice on itself.
About: Quadrant (instrument) - DBpedia Association
A quadrant is an instrument used to measure angles up to 90°. Different versions of this instrument could be used to calculate various readings, such as longitude, latitude, and time of day. Its earliest recorded usage was in ancient India in Rigvedic times by Rishi Atri to observe a …
Navigational Instruments - Celestial Navigation
QUADRANT. This instrument, shaped like a quarter of a circle, measured the angle from the vertical – not horizontal – and the line of sight to the body. It was suspended from a ring and had a weighted line hanging down, which crossed one of the angle numbers marked on the ring.
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