This is flash animation of Sun and Moon dial of Antikythera mechanism. The Antikythera mechanism, is an ancient mechanical calculator, also described as the first known mechanical computer designed to calculate astronomical positions. It was recovered in 1900-01 from the Antikythera wreck, but its complexity and significance were not understood until decades later. It is now thought to have been built about 150-100 BC. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe.

In this simulation the sun is represented by a yellow disc, the moon by a white. The moon's motion follows the position of the moon gear exactly. The sun moves just like the sun gear, but in the opposite directon. In the original this was accomplished by linking a second sun gear to the first by a vertical, cylindrical gear.

The sun gear (S) has 64 teeth. It meshes with the smaller of a 38,48 gear pair (purple). The 48 meshes with the smaller of a 24,127 gear (blue,green) pair. The 127 meshes with the 32 teeth of the moon gear (under the sun marked with M). The ratio of angular speeds of Gear Train can then be calculated as: ( 64/38 ) * ( 48/24 ) * ( 127/32) = (254/19) = 13.36842... This is a good approximation of the astronomical ratio 13.368267..

My actual purpose was to use my Gear Draw program to create gears with different number of teeth's and radius. To do this I wanted to make this animation. If you are a flash developer who want to create realistic gears you can also use my Gear Draw program to create any gear you want.