overall: 18.6 cm x 14.5 cm x 1.5 cm; 7 5/16 in x 5 23/32 in x 19/32 in
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. This brass astrolabe has a body and throne plate (there are no separate plates), a handle, ring, rete, alidade, pin, wedge, and index arm. It is signed d (/) q pnel in Gothic script – this may be an owner’s mark.
This isnstrument is sometimes referred to as "Parnel's astrolabe."
For a detailed description of this object, see Sharon Gibbs with George Saliba, <a href="https://repository.si.edu/handle/10088/2444"><I>Planispheric Astrolabes from the National Museum of American History</I></a>, Washington, D.C.: Smithsonian Institution Press, 1984, pp. 13, 150-151. The object is referred to in the catalog as CCA No. 304.
Robert T. Gunther, <I>Astrolabes of the World</I>, vol II, Oxford: Oxford University Press, 1932, p. 483.
Currently not on view
Gift of International Business Machines Corporation