The Antikythera Mechanism Episode 7 - Making 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: https://www.patreon.com/clickspring ________________________________________________________ A very special thank you to Patrons: Sinking Valley Woodworks (http://www.sinkingvalleywoodworks.com) Glenn Trewitt Christopher Warnock Mike Manfrin John A McCormick David Wurmfeld Lonnie Koehn Michael Harmon Jim Popwell Gary Levario Rollin W. Patrick, Jr. Pete Askew Andre van Soest Larry Pardi Bernd Fischer Rudolph Bescherer Jr Adam Slagle Jeremiah G. Mort Olof Haggren Tim Bray Steven R. Crider ________________________________________________________ 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 Hegner Scroll Saw: https://amzn.to/2IhteVW 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-papers/4/ Eclipse and Saros cycle info: http://www.mreclipse.com/Special/LEprimer.html http://www.mreclipse.com/Special/SEprimer.html https://eclipse.gsfc.nasa.gov/SEsaros/SEsaroscat.html https://eclipse.gsfc.nasa.gov/LEsaros/LEsaroscat.html https://www.eclipsewise.com/solar/SEhelp/SEperiodicity.html https://bit.ly/1CjqN0f http://www.jstor.org/stable/pdf/1006543.pdf https://en.wikipedia.org/wiki/Babylonian_astronomy https://en.wikipedia.org/wiki/Sicilian_Expedition https://en.wikipedia.org/wiki/Battle_of_the_Eclipse https://theconversation.com/how-eclipses-were-regarded-as-omens-in-the-ancient-world-81248 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0103275 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 https://soundcloud.com/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