The mechanical planetariums of modern times are almost all based on the ideas of Nicolaus Copernicus (1473 - 1543), who assumed the Sun to be the centre of the universe. He taught that the Earth makes three movements: it rotates around itself once in 24 hours, moves in a circular orbit around the Sun in a year, and with a third movement rotates its axis so that it always points in the same direction and not pointing to the Sun. In the early 18th century, the Earl of Orrery and other English nobles commissioned mechanical crank-driven planetary models from watchmakers, which have since come to be known in English as Orreries.
 
Cranking Around the Sun
The Copernican Orrery shows the movements of the inner planets Mercury and Venus, as well as the Moon and the Earth. The Earth rotates around its inclined axis, which always points in the same direction. One full turn of the crank on the gears made from rubber belts and grooved wheels corresponds to one week. It causes six different simultaneous movements, which are in approximate proportion to the actual orbital periods.
 
Educational
Many celestial processes can be explained from the Copernican (heliocentric) point of view, e.g. the Sun's movement through the zodiac or the conjunctions of Mercury and Venus with each other and with the Sun. In a darkened room the Sun with its brightly lit LED not only shows the change of seasons, but also the formation of the phases of the Moon, the eclipses, and the crescent phases of Venus.
 
Kit includes axles, magnets, pulley belts, planets, bearings, and LED light
Height: 29.5 cm, Diameter: 29 cm
Construction time: 20-40 hours (depending on experience)