Mechanical Tellurion Sun-Earth-Moon Orrery (Simulating the orbital paths of the Sun, Earth, and Moon)

This is a mechanical Sun-Earth-Moon orrery, which vividly simulates the orbital paths and relative positions of the Sun, Earth, and Moon through a precise gear transmission system.

This instrument is not only an exquisite mechanical model but also an intuitive astronomical teaching tool. It uses a hand crank to drive an internal gear set, causing the Earth model to revolve around the Sun, while the Moon model orbits the Earth, perfectly recreating the fundamental laws of celestial motion. Its core design precisely replicates the period ratio of Earth's and Moon's revolutions through combinations of gears with different tooth counts, making the demonstration both scientific and engaging.

At the center of the instrument is a golden Sun model, surrounded by a dial marked with "January" to "December," used to indicate the Earth's position in its orbit, thereby helping to understand the changing seasons. The Moon model is connected to the Earth model by an independent arm, moving around the Sun with the Earth while also rotating around the Earth itself.

The history of such instruments can be traced back to 18th-century "orrery," originally used to demonstrate the motion of solar system planets. Modern versions of the tellurion focus more on the relationship between the Sun, Earth, and Moon, widely used in primary and secondary school education, science museum exhibitions, and collections for astronomy enthusiasts. It can not only demonstrate Earth's rotation and revolution, and the Moon's revolution, but also vividly display astronomical phenomena such as solar and lunar eclipses and phases of the Moon, making it an excellent auxiliary tool for understanding basic astronomical concepts.