Georg Hartmann
Nuremburg, Germany
  Yale Peabody Museum of Natural History, Connecticut, USA
EMu user since 2003

AstrolabeAn astrolabe (from the Greek astrolabos, star-taker) is an astronomical calculating device used from ancient times into the eighteenth century. One of its uses was calculating the movement of the stars and planets. By 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 (called the rete) on the front of this astrolabe 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-centre 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 brass astrolabe has four plates, one of which may be a replacement. It was made in Nuremberg by Georg Hartman in 1537. Hartmann was an early 16th Century astrolabe maker and his factory in Nuremberg produced an impressive number of high quality brass and paper astrolabes. An apparent division of labour in Hartmann’s factory allowed some workers to make each part while others assembled the instruments.