An astrarium, also called a planetarium, is the mechanical representation of the cyclic nature of astronomical object

Astronomical object

Astronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe. The term astronomical object is sometimes used interchangeably with astronomical body...

s in one timepiece. It is an astronomical clock

Astronomical clock

An astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative positions of the sun, moon, zodiacal constellations, and sometimes major planets.-Definition:...

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The first astraria were mechanical devices. Archimedes is said to have used a primitive version that could predict the positions of the sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

, the moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

, and the planet

Planet

A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

s. On May 17, 1902 an archeologist named Valerios Stais

Valerios Stais

Valerios Stais was a Greek archaeologist. He was born in Kythera. He studied medicine and later archaeology. He became the director of the National Archaeological Museum of Athens in 1887 and held that post until his death. During that period he organized or participated in excavations in...

 discovered a lump of oxidated material with in it a mechanism with cogwheels

Gear

A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....

 that had been recovered from a shipwreck

Antikythera wreck

The Antikythera wreck is a shipwreck from the 1st or 2nd century BC. It was discovered by sponge divers off Point Glyphadia on the Greek island Antikythera in the early 1900s...

 near Antikythera

Antikythera

Antikythera or Anticythera is a Greek island lying on the edge of the Aegean Sea, between Crete and Peloponnese. Since the 2011 local government reform it is part of the municipality of Kythira island....

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