Italian Planispheric Astrolabe


The astrolabe is an astronomical calculating device used from ancient times into the eighteenth century. Measuring the height of a star using 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 Italian astrolabe has six plates, which have scales for latitudes ranging from 31 degrees to 52 degrees, as well a body with throne, handle, ring, rete, alidade, pin, wedge, and index. It is unsigned.


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. 13, 139-140. The object is referred to in the catalog as CCA No. 186.

Date Made: ca, 1475Date Made: ca 1475

Location: Currently not on view

Place Made: Italy

See more items in: Medicine and Science: Mathematics


Exhibition Location:

Credit Line: Gift of International Business Machines Corporation

Data Source: National Museum of American History

Id Number: MA.316757Catalog Number: 316757Accession Number: 215454

Object Name: astrolabe

Physical Description: brass (overall material)Measurements: overall: 15.4 cm x 10.6 cm x 2.9 cm; 6 1/16 in x 4 3/16 in x 1 5/32 in


Record Id: nmah_997132

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