The most famous ancient mechanical astronomical device yet found originates from ancient Greece around 150 BCE and is known as the Antikythera mechanism. Prior to its discovery in 1901, historical accounts of such mechanical technology was treated with caution by scholars, but such devices have since been proven a a part of classical antiquity.
This incredible mechanism (reproduced in photo) was a bronze astronomical clock, similar in sophistication to 18th century clock making and consisting of a series of complex mechanical gears designed to calculate and display the movements of the sun, moon, and five known planets at that time (Mercury, Venus, Mars, Jupiter, and Saturn). This ancient orrery could also predict eclipses, the phases of the moon and calculate the dates of the Olympic Games. In other words, it was an analog astronomical computer.
One person suggested as its inventor is Hipparchus of Nicaea (190 BC – 120 BC), who has been credited with discovering the precession of the equinoxes and inventing several astronomical instruments. He is also believed to have refined the planispheric astrolabe, an analog calculator in existence in various forms since 1000 BC, and capable of telling time and predicting the positions of the Sun, Moon, planets, and stars.
Another name put forward as it creator is that of Archimedes of Syracuse (287 BC – 212 BC), who is said to have invented the first planetarium, a rotating globe probably with some sort of gear mechanism, and capable of showing the movements of the “seven wanderers” (Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn). At the Siege of Syracuse (214–212 BC), the Roman General Marcus Marcellus was said to have taken two such devices, one of which he donated to a temple in Rome.
The Roman statesman Cicero (106BC – 43 BC) also refers to having seen two “bronze spheres” that modeled the movements of the heavens, one of which he said was made by Archimedes, the other by Posidonius of Rhodes (135 BC – 51 BC). As Cicero noted at the time:
“Suppose a traveler carried into Scythia or Britain the orrery recently constructed by our friend Poseidonius, which at each revolution reproduces the same motions of the sun, the moon, and the five planets that take place in the heavens every day and night, would any single native doubt that this orrery was the work of a rational being?”
Mysteriously, astronomical clocks seem to have disappeared from history following the fall of Rome in 476 AD and the ensuing dark ages that enveloped Europe as a result. Fortunately, by the 14th century such complex astronomical devices began to be constructed, once more, in Western Europe, based upon Greek manuscripts preserved in Arabic texts which helped fuel the Renaissance.