Dondi Dell'orologio Have? _verified_ - How Many Faces Did The Astrarium Of Giovanni

In his 1987 reconstruction and analysis, historian of astronomy Francis Maddison, along with others who studied Dondi’s manuscript, consistently states: The astrarium had two principal dials (front and back) for reading the time and calendar, plus the planetary indicators arranged on the upper seven sides. But if the question asks strictly for faces as in “clock faces” showing the time of day — the answer is two .

The Astrarium's design consisted of a complex system of dials and hands, which allowed it to display multiple astronomical and calendrical functions. According to historical records and existing literature, the Astrarium had seven faces, each with a distinct purpose:

While there were seven reading faces, the machine was unified by a central movement. The dials were not isolated clocks; they were driven by a central gear train, powered by weights. However, because each dial possessed its own engraved face, engraved circles, and moving hand, the count of functional faces is seven.

To replicate this mechanically, Dondi used a staggering array of nearly 300 hand-cut bronze gears. By dedicating a single face to each planet, he could ensure that the gear ratios were precise enough to predict planetary positions for decades without manual adjustment. The Legacy of the Astrarium

The defining feature of the Astrarium is its seven independent dial displays. Each dial was dedicated to a specific celestial body—the Sun, the Moon, and the five planets known to antiquity. These dials were arranged within a rectangular frame (often described as a trestle or horizontal frame).

To understand why Dondi needed seven faces, you have to understand the era's science. Based on the , planets didn't move in simple circles; they moved in "epicycles" (circles within circles).