Geochron world time clock

Geochron: Another Time, Another Timeless Tale

The Geochron World Time Indicator is a clock that doubles as a live map of where the sun is shining on the Earth. Back in its day, it was a cult piece that some have dubbed the “Rolex on the wall.” Wired’s recent coverage of the clock reminded us of just how cool it is on the inside. And to dig in, we like [Attoparsec]’s restoration project on his own mid-1980s Geochron, lovingly fixing up a clock he picked up online.

[Attoparsec]’s recent restoration shares insights into the clock’s fascinating mechanics. Using a synchronous motor, transparent slides, and a lighted platen, the Geochron works like a glorified slide projector, displaying the analemma—a figure-eight pattern that tracks the sun’s position over the year.

But if you’re looking for a digital version, way back in 2011 we showcased [Justin]’s LED hack of FlorinC’s “Wise Clock”, which ingeniously emulated the Geochron’s day-night pattern using RGB LEDs, swapping out the faceplate for a world map printed on vellum. That’s probably a much more reasonable way to go these days. Why haven’t we seen more remakes of these?

A Look Inside The Geochron Clock

There are plenty of cool clocks out there, and maps by their very essence are cool, too. But a map that’s also a clock — or is it a clock that’s also a map? — has to be the coolest thing ever.

Of course we’re talking about the Geochron, a world clock that makes the relationship between the Earth and the Sun clear and has graced the offices of executives who want to impress visitors with the global nature of their importance for decades. [Attoparsec] has long coveted one of these electromechanical beauties, and when a used one popped up online for a pittance, at least compared to what they cost new, he jumped at the chance.

The Geochron he ended up with was in need of some TLC, but surprisingly little considering its mid-1980s vintage. The real treat in the video below is getting to see how these wonderful devices work. They’re basically simple slide projectors. While we here in the future would simply do everything in software on a nice flat-screen display, the base map, night-day terminators, and calendar are all contained on transparent elements that move under the power of a synchronous motor across a lighted platen. The analemma display is particularly cool; an indicator tracks the Sun’s position over the Earth with a cam that encodes the equation of time in its shape, moving through its familiar bi-lobed loop as the seasons progress.

Any clock that comes with a set of blueprints for installation purposes is alright in our book, and kudos to [Attoparsec] for landing this prize and getting it back in shape. His description of it as “the greatest clock of all time” is apt, but perhaps with a little competition. Or maybe a lot.

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geochron_world_clock_clone

World Clock Simulates Night And Day

[Justin] always wanted a GeoChron clock, but since they run in the range of several thousand dollars apiece, he was pretty certain he would never have the chance to own one. Undaunted, he figured out a way to build a small version of the clock for himself, and he wrote in to share how it was done.

He first purchased a Wise Clock 3 from FlorinC, but he definitely wasn’t going to use the clock as it was originally intended. Rather than display the time in numbers, he pulled the Wise Clock apart and sandwiched a vellum printout of a world map in between the front face plates. A tweaked firmware image allows him to simulate day and night using the Wise Clock’s LED array. He also programmed the clock to take into account seasonal light patterns, as you can see in the video embedded below.

We think this is a great idea, and though we would probably use plain white LEDs if we built one, the RGB LEDs in the Wise Clock certainly provide a neat effect.

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