http://www.mlahanas.de/Greeks/Kythera.htm ts complexity is far in advance of that what was expected from a device that was build about 80 BC. The part found contains 32 gears. Its use of a Differential Gear to subtract the sidereal motion of the sun from that of the moon to produce the synodic month, the cycle of the phases of the moon, is remarkable and represents the first example of such gearing yet discovered. The full functions of the mechanism may never be known but it appears certain that it displayed the position of the Sun in the zodiac throughout the year as well as the phases of the moon. As such it can be considered as one of the first known computing devices. Price (1974) speculated that it may also have displayed the positions of the planets as well, thought the gearing required to do this is missing from the fragments that were recovered. “Planetaria” are considered have been also build by Archimedes and they also could be used for educational and research purposes. This device has had me thinking on and off years, was it made 80 BC, i doubt it, it seems way to advanced for that date.