~~~  ESSENCE OF THE ANTIKYTHERA MECHANISM  ~~~
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Update 8th of August 2008: A four year cycle dial has been added,
as described in Nature 454 (2008) p. 614-617

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T. van Vark fecit     Ede NL 2007

A tribute to the Ancient Maker, D. de S. Price, M.T. Wright, M. Edmunds and all the participants in the AMRP and to Yolande Spaans who delicately directed my choice for an interludium project.

Lucubrations                    2007
steady like heavens
gears for sober magisters
myths for the masses


                                            T.


This model of the Antikythera Mechanism is made after schematic fig. 5 in Nature vol. 444 and includes a Hipparchos Solar Mechanism of my own design. However I see a-1 as an output to drive a hypothetical planetarium as illustrated.
The Antikythera Mechanism cannot easily be driven from a-1 as any engineer will understand, taking into account the gear ratios. My input is the disk containing the lunar phase mechanism. This works beautifully and allows very subtle setting even with the additional load of my hypothetical planetarium.
From the engineers point of view d-2 would be the perfect input gear. With a crown gear exactly like a-1 engaging d-2 and a little crank, the Antikythera Mechanism (and planetarium) can be driven smoothly and subtly. Experiments confirm this. There is however as far as I know no sign of this arrangement in the original, it is purely my personal curiosity that made me investigate this.
My geocentric planetarium is based on modern data of planetary motion and is realised by conventional asymmetrical spur gear differentials as described in engineering text books. It is similar in principle to Mr. Wright's but rather different in details. I do not know of any detailed description of Mr. Wright's excellent work so I worked this out myself. As it represents the same solar mechanism, with good approximations, the differences cannot be great. Mine has 28 gears.
The strange ratio of a-1/b-1 48/223 is an advantage here. My planetarium, after independent use, can be resynchronised with the Antikythera Mechanism from anywhere in a very wide window of time. Since a-1/b-1 is mirrored in my planetarium to provide a one-year-wheel there the actual ratio is irrelevant. I made b-1 with 223 teeth because I had to make it anyway for e-3 and the information does not exclude this.









08-08-2008
Added: A four year cycle dial as described in Nature 454 (2008) p. 614-617




View video of Antikythera Mechanism in action
(Video recorded outdoors: Please note that the sounds in the
background are chirping birds, not squeeking gears.)

Click here for "The making of"













Experiment
A crown wheel identical to a-1 driving d-2 makes an excellent drive as confirmed by this experiment.







Hypothetical Geocentric Planetarium* driven by the outgoing shaft of the Antikythera Mechanism.

*after Apollonius of Perga


Haiku                    2008
finished yesterday
today the first crocuses
kissed my retinae


                                   T.














Click here for "The making of"




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