Most of us probably aspire to build nothing more complex this year than a gingerbread house. (Tick tock.) Videographer John Pavlus spent much of 2010 writing and shooting a video about an Apple engineer, Andy Carol, who designed and built a fully functional eclipse-predicting machine, a replica of an ancient Greek device, out of 1,500 Lego Technic parts and 110 gears.

It's so fun that I watched the video, commissioned by Nature Publishing Group's video group (Scientific American is part of Nature Publishing Group and Pavlus used to work for Scientific American—bazinga!) a few times without even realizing I was looping.

But a few questions remained, so here are answers from Pavlus:

Why did you make this video?
Adam Rutherford—a good friend whom I've collaborated with on videos for Nature in the past—approached me about a year ago and said he really needed an amazing film to be made about this amazing device. He asked me to devise a few concepts, and the one they ended up picking was inspired by "exploded view" engineering diagrams: clean, futuristic lines, isometric perspective, mechanical parts floating in midair. Since Andy Carol is a consummate engineer, I thought it would be the perfect way to visually present the device—and help actually explain it!

As for me, as a science writer/filmmaker, I've been fascinated by the Mechanism for years. I was incredibly excited to get this chance to learn so much about it.

I really wanted the visuals to feel physical, to have weight and texture—not be abstract and phony like CGI. That was why I chose stop-motion animation. We also shot most of the animation "on twos" (12 frames per second vs. 24) to save production time but also to give it a slightly handmade, herky-jerky DIY look that seemed to match Andy's own "hacker" way of working. (Fantastic Mr. Fox and Wallace & Gromit were also shot "on twos").

I also wanted to highlight the physical process in the film as well. That's why it's book-ended with raw-looking live action showing the "scaffolding" of the film production—the lights, the camera rig, etc. I wanted it to be as if the Lego device was pulling us into a different, more wondrous world the closer we peered at it. 

I felt it was very important to set the device in motion at the beginning and then blow it apart/put it back together again while it was still performing the calculation. So the eclipse date that the animation ends on is actually the real, bona fide positions of the dials that the machine would land on of you just hand cranked it with no magical animation happening. But that is the "story," as it were of the video—following the path of this intricate mechanical calculation as it winds its way through the various modules of the machine and finally ends on a future eclipse date.

Misha Klein, the animator, had quite a time keeping all of it straight as he shot the thing one frame at a time, 12 times per second...! But his attention to detail is incredible, so he nailed it.

What was the best part about making the video?
The best part was the close creative collaboration I had on the set in Portland, Ore., with Misha and Andy Carol. We were all there for a week prior to starting the animation—to shoot the live-action portions and just get everybody on the same page, visually. Misha is a top-shelf animator who was working on this project for the love of the science behind it, so he brought incredible professional experience and creativity to my concept; and Andy was indispensable to have on-hand to advise on the many, many mechanical issues that arose while trying to figure out how to shoot the damn thing. Some of the best shots in the film, like the "floating rack" in the middle, came out of all three of us putting our heads together to solve a creative problem, and it ended up being more cool than any one of our ideas would have been individually. I hadn't directed an animated film before this, and Misha was amazing about being open-minded and game for anything, and never flat out saying, "No, we can't do that." (Well, sometimes he did, but only when I really pushed him!) And Andy's breadth of knowledge was amazing—even in terms of filmmaking procedure and visual ideas. He really blew everyone away on the set.

How long did it take to make the device and video?
Andy built the device from scratch in about 30 days. Preproduction took forever—most of the spring and summer. We filmed in Portland for a week in September, then I went back to New York and directed the animators' stop-motion work via daily phone calls and email/video updates for about a month and a half. Postproduction took a few weeks all told. But from very beginning to very end, it took us all of 2010.

So this Lego-built mechanism really works to predict the next solar eclipse?
Absolutely. It predicts solar and lunar eclipses to the exact year, date, and time of day accurate to within two hours, out to about a century or two in the future. Beyond that, mechanical effects like flexion and friction cause drift in the calculations done by the gears, but it is still accurate to the day, if not the exact time.

Where will this Lego machine "live" in the future?
In Andy's garage, I imagine—the same place his other Lego vintage computers live! He did bring it to Google's SciFoo Camp earlier this year, and is currently demo-ing it in high school science classrooms.

Where is the original Greek mechanism currently housed?
That I don't know. You'll have to consult Wikipedia or Nature. [So I did: it's at the National Archaeological Museum in Athens. And there are replicas elsewhere. Check Wikipedia.]


For more, check out Pavlus' behind-the-scenes blog.

Find additional details on the antikythera in Tony Freeth's Scientific American article "Decoding an Ancient Computer," which also appears in "The Best American Science Writing 2010."