The large room of the Paduan "Palazzo della Ragione" (The Hall of Reason) has exhibited "padua sidus preclarum": Dondi dall'Orologio and Padua of Carraresi. All the exhibition centers on the evidence of the main and irreplaceable presence which astrology had in the social life of the Middle Ages. Among other things, the show presents the faithful reconstruction of Giovanni Dondi's "astrario", a complicated astronomic-astrologic "time-piece".