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The Antikythera Mechanism Episode 7 - Constructing The #Saros & #Exeligmos Train, by Clickspring

In this video I make the gearing that drives the #eclipse prediction function of the mechanism. Be sure to check out the reference links below for more info on the Saros cycle, and other eclipse related stuff.

[EDIT: At 2:57 there is a typo - the final number in the denominator of the upper expression should be a 30 as per the sketch rather than 90 - Cheers :) ]

If you would like to help support the creation of these videos, then head on over to the Clickspring Patreon page:   / clickspring  
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You can also help me make these videos by purchasing via the following Amazon Affiliate links:

Cameras used in this video:
Panasonic GH5 - https://amzn.to/2rEzhh2
Panasonic X920 - https://amzn.to/2wzxxdT

Tools & Shop Products:
"Solidworks 2013 Bible": http://amzn.to/2FObS1D
"Gears From The Greeks", Derek de Solla Price: http://amzn.to/2pii4ZD
Sherline Lathe: http://amzn.to/2pnXM19
Dykem 80300 Steel Blue Layout Fluid, Brush-in-Cap (4oz): http://amzn.to/2HGPaJJ
Optivisor Headband Magnifier: http://amzn.to/2HFg1FU
Saint Gobain (Norton) - 4 Arkansas Stones + case: http://amzn.to/2HCOAMX
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Super Pike Saw Blades Size 4/0 pkg of 144: http://amzn.to/2IO6aPw
Blue Matador Abrasive Paper - https://amzn.to/2IAFiBT

Abbreviated Transcript:

01:29 This leads to what's known as a Saros series, where over a period of well over a thousand years, roughly 70 to 80 eclipses, will follow one after the other in sequence, separated by the regular interval of 223 lunar months.
05:30 Now the exact nature of that technology is the big question, and we may never know for sure. But we can certainly try a few things out and see what might have been the case. So with that in mind, its time to open up a hole position that I marked back in episode 2. This is the pivot location of the E assembly, and its a perfect opportunity to make the very first hole in the mechanism using some of that ancient tool tech: The Pump Drill.
18:34 The main plate was then opened up, and the square bearing hole formed. These two positions are essentially absolute locations, governed by the dial artwork. And depthing could have been conducted from these positions before filing out this square hole. But at the risk of the position almost certainly moving as the square was formed, and so compromising the depth.
20:44 The height of the Saros pointer assembly is set by the height of the bearing in which it sits, and that height can be easily set by this little spacer. I originally made it slightly oversized, but its a straight forward job to set a clearance of just a few hundredths of a millimeter, by simply abrading the spacer until the barest daylight remains between the adjacent assemblies No special tools, or absolute measurement are required. Just keen eyesight, and a flat abrasive surface.

References:

Gears From The Greeks - Derek de Solla Price: http://amzn.to/2pii4ZD

The CT and PTM data that the AMRP have made publicly available can be found here: http://www.antikythera-mechanism.gr/data

Gear schematic can be found in Tony Freeth's 2012 research paper:
http://dlib.nyu.edu/awdl/isaw/isaw-pa...

Eclipse and Saros cycle info:

http://www.mreclipse.com/Special/LEpr...
http://www.mreclipse.com/Special/SEpr...
https://eclipse.gsfc.nasa.gov/SEsaros...
https://eclipse.gsfc.nasa.gov/LEsaros...
https://www.eclipsewise.com/solar/SEh...
https://bit.ly/1CjqN0f
http://www.jstor.org/stable/pdf/10065...
https://en.wikipedia.org/wiki/Babylon...
https://en.wikipedia.org/wiki/Sicilia...
https://en.wikipedia.org/wiki/Battle_...
https://theconversation.com/how-eclip...
http://journals.plos.org/plosone/arti...

Credits:

Clips from "The 2000 Year Old Computer" courtesy Images First Ltd.

Digital image of the Back Dial of The Antikythera mechanism courtesy Tony Freeth, Images First Ltd

Final track is "Fading" by Sappheiros - visit   / sappheirosmusic  

Other music:
https://taketones.com,
http://www.epidemicsound.com/

Aerial eclipse footage courtesy NASA

Eclipse Corona footage courtesy Joe Maddox

The Antikythera Mechanism Episode 7 - Making The Saros & Exeligmos Train, by Clickspring