This astrolabe, from the Vincenzo Viviani bequest, seems to have been made for teaching purposes, perhaps by the scientist himself. The wooden, copper-edged mater carries: a tympanum with the celestial vault; a tympanum with the main stars; a copper tympanum for latitudes 38° and 43° (from Sicily to Pisa); a cardboard tympanum for latitude 43° (Pisa); a rete; and a cardboard disk with a shadow square. The limb, rete, and index are made of copper, as is the back, which features an alidade, a disk with shadow square, a windrose, and a table for ecclesiastical dates.