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Non-Functional Planispheric Astrolabe

Non-Functional Planispheric Astrolabe

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Description
The astrolabe is an astronomical calculating device used from ancient times into the nineteenth century. Measuring the height of a star using the alidade on the back of the instrument, and knowing the latitude, one could find the time of night and the position of other stars. The openwork piece on the front, called the rete, is a star map of the northern sky. Pointers on the rete correspond to stars; the outermost circle is the Tropic of Capricorn, and the circle that is off-center represents the zodiac, the apparent annual motion of the sun. Engraved plates that fit below the rete have scales of altitude and azimuth (arc of the horizon) for specific latitudes. This silver-colored metal astrolabe base with throne, handle, ring, an alidade (without holes for sighting a star) with pin, a rete, three plates, and a wedge at the front that holds the instrument together. The instrument is unsigned and undated. Inscriptions are in Arabic. The scales are neatly divided but largely meaningless.
For a detailed description of this object, see Sharon Gibbs with George Saliba, Planispheric Astrolabes from the National Museum of American History, Washington, D.C.: Smithsonian Institution Press, 1984, pp. 169-170. The object is referred to in the catalog as CCA No. 2570.
Location
Currently not on view
Object Name
astrolabe
Physical Description
metal (overall material)
Measurements
overall: 15.1 cm x 9.6 cm x 1.8 cm; 5 15/16 in x 3 25/32 in x 23/32 in
ID Number
MA.315064
catalog number
315064
accession number
214009
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History
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