BBC doc on Antikythera Mechanisim

[madd0ct0r]

http://www.bbc.co.uk/iplayer/episode/b0 ... _Computer/

That twin gears with offest axis and pin and slot tying them together to model an planet moving around an ellipse is fucking incredible.

[Johonebesus]

BBC doesn't let anyone outside the U.K. see videos on their website you know. Is it available anywhere else?

[madd0ct0r]

The documentry focus on the different guys who focused on solving it - explaining their different strategies, ideas and mistakes. There's a rather nice point where Tony Freeth, who leads the documentary talks about the 53 tooth gear. "I decided Wright's 53 gear was too strange a number, too hard to make. I argued it was 54. It was the biggest mistake of the project."

Wright's model: http://www.youtube.com/watch?v=4eUibFQKJqI

Wright solved the elliptical gear problem and deduced (correctly) there was a planetarium on the front of the model. The greek model was geocentric, so a planaterium is difficult since the planets moves backwards at some points and constantly vary their speed. Wright's planetarium is a thing of beauty, but fiendishly complex.
The most recent addition to the mechanisim is the mathematicians taking the same elliptical gears, and discovering you could model each planet using only 2 pairs of gears each, a much simpler solution.

The mechaninism can be seen here: http://en.wikipedia.org/wiki/Antikythera_mechanism

[Broomstick]

I think it might be on Netflix in the US, at least, it sounds very much like a documentary on the antikythera mechanism I watched on Netflix fairly recently.

[Eternal_Freedom]

If you can watch this documentary doe so, it's excellent. Unlike stuff on BBC 2 (or Channel 5) it wasn't dumbed down. They explain all the detailed stuff but in a way you can understand. I second the description of Wright's model as absolutely beautiful.

I was lucky enough to have a lecture from Prof. Mike Edmunds (the guy int he documentary) at my uni a few years back. The level of detail in the design is simply stunning.

[Crossroads Inc.]

I hope I do not get picked upon too much for this... But I have always wondered how much of the 'reconstructed machine' is guess work?

A lot of researches point to modern models and say "Look! we got it to accurate predict astronomical events and orbits! We've fixed it!"
But..
Is there any way to know that we "fixed" it the correct way?
I mean, if you were giving a computer with half the parts missing, you could in time rebuild it to where it would function. But what ways are they about to say "This is how it was supposed to work originally"

I am 'guessing' it may do with, there only being one "correct" way of making it work? Something like that?

[LaCroix]

As far as I remember from a doc I've seen some years ago, they couldn't reproduce it until someone took some very fancy pictures of it in a special light-dome he made (something about shades enhancing outlines), which showed them a few more details (including engravings) and gave them the clues what it was supposed to be.
Then they thought they were clever and "fixed it" by changing some gears in ways they deemed "more logical". Only after going back and using the right numbers and setup derived from the actual object, it worked. So they are pretty sure the model is accurate.

Basically, with the parts they had, there was only one way to make it work right - there are only so many ways to divide and multiply by gears in a given space to get to the correct numbers.

[Simon_Jester]

It's an analog mechanical computer, so yeah, like other such devices, if you try to take it apart and put it back together without detail knowledge of how it works, you're probably going to get it wrong.