The earth divided by 'climates'
The ancient astronomer and geographer Claudius Ptolemy divided the earth by latitude into seven 'climates' in his book Geographia (or Cosmographia). In this astrolabe there are seven projections on latitude plates that correspond to Ptolemy's climates. Framed by the rete's star pointers you may just be able read part of one of the climate inscriptions: 'CLIA 5 LAT 41'. Ptolemy's Geographia illustrates the close relationship that was understood between geography, astronomy and time, by defining his climates according to the lengths of the longest days in those latitudes.
Astrolabe, Hispano-Moorish, c.1260 (Inv. 43504)