Astrolabe
Related Category: Astronomy: General
(s´trlb), instrument probably used originally for measuring the altitudes of heavenly bodies and for determining their positions and movements.
Astrolabe
A 16th century astrolabe.
The astrolabe is a historical astronomical instrument used by classical astronomers and astrologers. It was the chief navigational instrument until the invention of the sextant in the 18th century.
Astrolabe
From LoveToKnow 1911
ASTROLABE (from Gr. oi rrpov, star, and Xa(3€Iv, to take), an instrument used not only for stellar, but for solar and lunar altitude-taking. The principle of the astrolabe is explained in fig. 2.
astrolabe
An Arabic and medieval European sighting instrument on an altazimuth mounting, used to determine the elevation above the horizon of celestial objects.
astrolabe
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astrolabe is a historical astronomical instrument
Measuring instrument ...
Astrolabes. "Star-finders" or astrolabes were created by Arab astronomers to solve complicated astronomy problems. One side of an astrolabe contained a detailed star map.
Astrolabe. An ancient instrument used for measuring the altitudes of celestial objects.
Astrometry. The branch of astronomy that deals with precisely measuring the positions of objects on the celestial sphere.
astrolabe: an early astronomical instrument in the form of a heavy disk (the mater) which was suspended vertically and had an angular scale marked around it (the limb). A coplanar klimate and an alidade rotated about its centre.
Astrolabe
(a) Ancient Arabic and medieval alt-azimuth device comprising two or more flat, metal, calibrated discs, attached so both or all could rotate independently.
ASTROLABE
An astrolabe is an instrument that was used to determine the altitude of objects (like the sun) in the sky. It was first used around 200 B.C. by astronomers in Greece. The astrolabe was replaced by the sextant.
Brass astrolabe
Brass astrolabes were developed in much of the Islamic world, chiefly as an aid to finding the qibla. The earliest known example is dated 315 (in the Islamic calendar, corresponding to 927-8CE).
Other than astrolabes, the oldest known flat sky map is a Chinese paper scroll, over 2 metres long, now believed to date from as early as the 7th century AD.
astrolabe (NASA Thesaurus / NASA SP-7, 1965) 1. In general, any instrument designed to measure the altitudes of celestial bodies.
2. Specifically, an instrument designed for very accurate celestial altitude measurements, as in survey work.
200 BC - Astrolabe used by Greeks
150 BC - Rhodes observatory
129 BC - Hipparchus' star catalog
105 BC - Alexandria observatory and College of Technology under Heron
52 BC - Shou-chang uses armillary ring ...
Ptolemy also contributed substantially to mathematics by advancing the study of trigonometry, and he applied his theories to the construction of astrolabes and sundials.
Arabic astronomers using a variety of instruments, including astrolabes at the observatory of Taqf ad-Din at Istanbul in 1577.
700-96 - Brass astrolabe constructed by Muhammad al-Fazari based on Hellenistic sources
ca. 777 - YaqÅ"b ibn TÄriq wrote Az-Zij al-Mahlul min as-Sindhind li-Darajat Daraja based on Brahmagupta and Surya Siddhanta ...
Alidade: A rule equipped with simple or telescopic sites and used for determination of direction (as part of an astrolabe).
AM or Amplitude Modulation: Imposing a signal on transmitted energy by varying the intensity of the wave.
Even earlier documents, such as the Mul Apin tablets and astrolabes contain descriptions of constellations which conform to some, if not all, of the twelve that form the modern Zodiac.
It does this by measuring angular distances, like the altitude of the sun, moon and stars. The sextant was invented independently in both England and America in 1731. The sextant replaced the astrolabe.
 See also: Astronomy, Earth, Time, Planet, Sun
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