Non-Functional Planispheric Astrolabe

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

See more items in: Medicine and Science: Mathematics

Exhibition:

Exhibition Location:

Data Source: National Museum of American History

Id Number: MA.315064Catalog Number: 315064Accession Number: 214009

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

Guid: http://n2t.net/ark:/65665/ng49ca746b4-d7c1-704b-e053-15f76fa0b4fa

Record Id: nmah_997062

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