Inv. No. 53558
A typical instrument from the Louvain workshop of Gemma Frisius, signed, ‘Regnerus Arsenius Nepos Gemmæ Frisij fecit Louanij anno 1565.’ There are two astrolabes in a single instrument. The front is the standard projection, as published, for example, by Stöffler in 1513, here with the distinctive tulip motif worked into the star map or ‘rete’, as used by the makers of Louvain. The reverse has a universal astrolabe, that is, one that can be used in any latitude, based on the projection of the celestial sphere described in Gemma’s De astrolabo catholico of 1556. The book also describes the ‘nautical quadrant’ for calculations in navigation, which is included on an inner surface of the astrolabe. Writing, printing, publishing and instrument-making were closely intertwined.