astrolabe


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astrolabe

(ăs`trəlāb), instrument probably used originally for measuring the altitudes of heavenly bodies and for determining their positions and movements. Although its origin is ancient and obscure, its invention is frequently ascribed either to Hipparchus or to Apollonius of Perga. For many centuries it was used by both astronomers and navigators. A simple astrolabe consisted of a disk of wood or metal with the circumference marked off in degrees. It was suspended by an attached ring. Pivoted at the center of the disk was a movable pointer called by Arab astronomers the alidade. By sighting with the alidade and taking readings of its position on the graduated circle, angular distances could be determined. Mariners, if sufficiently skilled in navigation, could use the astrolabe to determine latitude, longitude, and time of day and as an aid in making other calculations. It was much used on voyages of discovery in the 15th cent. and was important until the invention of the sextant in the 18th cent. The more elaborate astrolabes bore a star map (the planisphere, a circular map, was added by Hipparchus), a zodiacal circle, and various other useful or decorative devices.

astrolabe

(ass -trŏ-layb) An instrument, dating back to antiquity, used to measure the altitude of a celestial body and to solve problems of spherical astronomy. From the 15th century it was employed by mariners to determine latitude, until replaced by the sextant. There have been various types of astrolabes. One simple form consisted of a graduated disk that could be suspended by a ring to hang in a vertical plane. A movable sighting device – the alidade – pivoted at the center of the disk. Modern versions are still used to determine stellar positions and hence local time and latitude. See also prismatic astrolabe.

Astrolabe

(religion, spiritualism, and occult)

An astrolabe is a mechanical device that, prior to the development of the sextant, was widely used by mariners. Said to have been developed by Hipparchus, greatest of the ancient Greek astronomers (although some scholars give Ptolemy the honor), the astrolabe was used by astrologers when they erected horoscopes to determine the positions of the planets. (Prior to the development of ephemerides, it was necessary to actually look at the heavens when casting a horoscope.). The term astrolabe means “taking the star” in Greek, so it could be used to refer to any instrument for observing the stellar dome. Thus, in the early medieval period, astrolabe was often applied to the armillary sphere, a different instrument. The device now called an astrolabe is more properly termed a planispheric astrolabe. Originally Greek, this instrument was lost to western Europe until its reintroduction by Arabic sources.

Sources:

DeVore, Nicholas. Encyclopedia of Astrology. New York: Philosophical Library, 1947.
Tester, Jim. A History of Western Astrology. New York: Ballantine, 1987.

Astrolabe

 

a bay on the northeast coast of New Guinea (Maclay Coast). The bay is about 37 km long and 34 km wide, with depths of 40–106 m. The coast is hilly and covered with tropical vegetation. Many points on the coast have Russian names—for example, Konstantin Harbor, Cape Novosil’skii, Cape Koptev, and the Gogol River—as a result of the work done by the Russian traveler N. N. Miklukho-Maklai in New Guinea.

astrolabe

[′as·trə‚lāb]
(engineering)
An instrument designed to observe the positions and measure the altitudes of celestial bodies.

astrolabe

an instrument used by early astronomers to measure the altitude of stars and planets and also as a navigational aid. It consists of a graduated circular disc with a movable sighting device
References in periodicals archive ?
There are many uses of an astrolabe, said Dr Hogendijk.
The astrolabe is a centuries old scientific instrument and it was exported to Europe from Lahore because world's finest astrolabes were made by Lahore's craftsmen,' he said.
David Mearns, expedition leader of Blue Water Recoveries, which conducted the excavation, told TheWeek, "The mariner's astrolabe we discovered is the oldest known example of this type of navigation device found anywhere in the world.
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The last, and most arduous, occurred in 1837-40, when a second ship, the Zelee, joined the Astrolabe, to not only circumnavigate the globe, but make two probes into Antarctic waters.
We three seem to be the only brass astrolabe makers in the world.
He moves to stand beside her and holds up the astrolabe by the ring at the top.
TREASURES FROM THE SUNKEN GALLEON, SAN DIEGO (1600): THE GOLD SEAL OF ANTONIO MORGA AND A NAUTICAL ASTROLABE.
The inventions, which are displayed with the help of hologram technology, include the camera obscura of al-Haytham, astrolabe, surgical tools, turbine of Hassan al-Jarrah and water-raising machine of Al Jazari.
The astrolabe, which was invented by the ancient Greeks during the second century BC and whose name means "star-taker" in Greek, is a portable inclinometer (an instrument for measuring angles of slope, elevation or depression of an object with respect to gravity) which was used to assess the positions of the sun, moon, planets, and stars, in addition to keeping time and navigation
CALVO LABARTA, "Ibn Baso's astrolabe in the Maghrib and East", From Baghdad to Barcelona.
Drawn, in its curators' words, "from every region and every period, and created from every kind of material in the Muslim world," the exhibits embrace paintings, textiles, costumes, manuscripts, ceramics, medical texts, books, tiles and musical instruments and stretch geographically from China (where porcelain and silk were manufactured both for local Muslim communities and for export to, for instance, Persia) to Spain (through a rare intricately decorated 14th-century brass astrolabe inscribed in Arabic, Hebrew and Latin and probably made in Toledo).