Antikythera Mechanism

Mechanical Design Fall 2011

This was my final project in the Phoenix Innovation, LLC design team and it targeted several key areas of mechanical design; gears, linkages, efficient design, managing lead-times, budget and schedule tracking, and the build, test, iterate fabrication process. The goal of the Antikythera Mechanism project was to design a modified version of the Antikythera Mechanism with a Gregorian (Western) Calendar instead of an Egyptian Calendar and using a scaled and simplified design of the original mechanism to reduce complexity.

It is a challenging feat to properly illustrate the significance of this mechanism or its importance in forcing a re-evaluation of the technology available in the B.C. era. The box contained 32 gears assembled into a mechanism which accurately reproduced the motion of the sun and moon relative to the celestial sphere. There was nothing like this until at least 1000A.D. and on its discovery there were even some who theorized that it may have been dropped into the wreck on a later date or that it was alien in nature.

Unfortunately the plan of its gearing and a full understanding of its operation could not be achieved until 1971 when De Solla price used gamma rays to penetrate the interior of the mechanism though the calcerous block the components were still embedded in. Careful counting of the teeth and the way the gears meshed showed that "the gear ratios could be associated with well-known astronomical and calendrical parameters" (Price) and allowed the almost complete description of how the device must have functioned.

The ancients observed that eclipses appeared to follow a cycle of 18 years, 11 days, and 8 hours. If there was an eclipse of the sun at 10am on a certain date, then there was a very good chance there would be a similar eclipse on a date 18 years and 11 days in the future at 6pm (8 hours later in the day). Three such cycles would mean that a similar eclipse was probable 54 years and 34 days in the future at about the same time of day as the original eclipse.

The full three Saros cycle is called a Triple Saros. If an eclipse occurs on the first Saros, a similar one may occur 8 hours later during the 2nd Saros cycle. Another similar eclipse may happen 16 hours later during the 3rd Saros cycle. The 4th Saros cycle would have advanced 24 hours which is an entire day and the process repeats.

A Synodic month is a lunar month from full moon to full moon. It defines when the moon returns to the same position in the sky relative to the sun. In the 18 year, 11 day, and 8 hour Saros cycle there are 223 synodic months. This completes one Saros cycle of eclipses. 19 years is 235 synodic months which is a different yet equall. Knowing these values allowed the ancients to interrelate the advance of years and eclipse cycles.

The project was designed in Solidworks and then rapid prototyped.

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