The Antikythera mechanism ( AN-tih-kih-THEER-ə) is an Ancient Greek hand-powered oldest example of an analogue computer used to predict astronomical positions and eclipses decades in advance. It could also be used to track the four-year cycle of athletic games which was similar to an Olympiad, the cycle of the ancient Olympic Games.

This artefact was among wreckage retrieved from a shipwreck off the coast of the Greek island Antikythera in 1901. On 17 May 1902, it was identified as containing a gear by archaeologist Valerios Stais. The device, housed in the remains of a wooden-framed case of (uncertain) overall size 34 cm × 18 cm × 9 cm (13.4 in × 7.1 in × 3.5 in), was found as one lump, later separated into three main fragments which are now divided into 82 separate fragments after conservation efforts. Four of these fragments contain gears, while inscriptions are found on many others. The largest gear is approximately 13 centimetres (5.1 in) in diameter and originally had 223 teeth.

In 2008, a team led by Mike Edmunds and Tony Freeth at Cardiff University used modern computer x-ray tomography and high resolution surface scanning to image inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine. This suggests that it had 37 meshing bronze gears enabling it to follow the movements of the Moon and the Sun through the zodiac, to predict eclipses and to model the irregular orbit of the Moon, where the Moon’s velocity is higher in its perigee than in its apogee. This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine’s construction. There is speculation that a portion of the mechanism is missing and it also calculated the positions of the five classical planets.

The instrument is believed to have been designed and constructed by Greek scientists and has been variously dated to about 87 BC, or between 150 and 100 BC, or to 205 BC. In any case, it must have been constructed before the shipwreck, which has been dated by multiple lines of evidence to approximately 70–60 BC. In 2022 researchers proposed that the initial calibration date of the machine (not its actual date of construction) could have been 23 December 178 BC. Other experts propose 204 BC as a more likely calibration date. Machines with similar complexity did not appear again until the astronomical clocks in the fourteenth century.

All known fragments of the Antikythera mechanism are now kept at the National Archaeological Museum, Athens, along with a number of artistic reconstructions and replicas to demonstrate how it may have looked and worked. *https://en.wikipedia.org

for more information: https://greekreporter.com/2022/09/15/antikythera-mechanism-secret/

For Ted, seeing the Antikythera Mechanism was a must! The fact that ancient man was capable of producing such a mechanism is fascinating!! Note the Ancient Greek writing that describe of what the mechanism does and how to operate it.