Ulysse Nardin Planetarium Copernicus. One single movement of mechanical excellency plus a stroke of pure genius combine Ptolemy’s geocentric universe with the Earth at its center, and Copernicus’ heliocentric universe with the Sun at its center. This allows the reading of the astronomical positions of the planets in relation to the Sun and the Earth. A perpetual calendar indicating the months and the sign of the zodiac completes one turn in 365.24 days at the exterior. Ltd to 100 sets.