By the time world-famous Italian astronomer and mathematician Giovanni Antonio Amedeo Plana published his book theorizing the motions of the Moon on 1832, he had already begun constructing his Perpetual Calendar: an amazing mechanical device that allows anyone to easily discover details about any date between years 1 and 4000.
Plana’s Perpetual Calendar is discreetly hanging on the sacristy of the small Chapel of Merchants and Bankers in Turin, Italy. It operates by turning a wooden handle below the calendar’s adorned golden frame.
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