Many public clocks were designed to show much more than the time of day. In fact, looking at many civic clocks, the time of day is dwarfed by other dials, figures, and displays. These astronomical aspects of the clock, such as reading the sign of the zodiac, the month, the lunar phase, and the day of the week were an integral part of the clock.
The emphasis on the astronomical function of clocks is most apparent from Giovanni di Dondi's 1364 Astrarium clock in Padua. It was a weight-driven clock with seven dials showing the astrological motions of the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn. The lower section of the clock had a 24-hour dial, a dial for fixed feasts of the Church like the Nativity, a dial movable feasts like Easter, and a dial for the moon phases. The mechanism was extremely complicated and has fascinated modern clock makers who have attempted to reproduce Giovanni's clock (replicas can be found in the Smithsonian Museum in Washington and Science Museum in London, among others). Giovanni's father Jacopo had designed an earlier (1344) astronomical clock for the Palazzo Capitano in Padua that included a 24-hour face, a calendar dial, and signs of the zodiac.
Clearly, these public mechanical clocks were more than instruments for telling the time of day. As discussed in the other section of this exhibit, the time of year with its associated zodiac and planetary movements was actually much more important to most people in the Middle Ages than the time of day. As a viewer stood in front of such large, impressive astronomical clocks, the wonder of the mechanism and the heavens blurred. Something magical and divine, not mundane, was at work.