# Laser Cutting Orreries

An orrery is a clockwork model of the solar system, demonstrating the machinations of the planets traveling around the sun in a sublime pattern of epicycles. A tellurion is a subset of the orrery, showing the rotation of the Earth around the sun, and the orbit of the moon around the Earth. [HuidongT] created his own tellurion out of laser-cut parts and just a few bits of copper tubes and bearings.

This project was originally inspired by the holzmechanik, a tellurion constructed from plywood gears and brass tube. [HuidongT] saw a few shortcomings in this project: the Earth didn’t spin and the moon didn’t orbit with its natural five-degree inclination. [Huidong]’s tellurion would have these features and include an illuminated sun, demonstrate the change of the seasons, and show lunar and solar eclipses.

While there was a bit of math involved in figuring out the gearing, it’s not much: the Earth would go around the sun every 365.25 days, the moon would go around the Earth every 27.32 days, and there is a difference between sidereal and solar time. A quick script made quick work of the math, and anyone can easily find tools to create gears given a diameter and the number of teeth.

The fabrication of this tellurion was made with acrylic on a laser cutter with a handful of 3D printed parts. The electronics are simple enough — just a motor and a few LEDs, and the completed project works well enough. You can check out a video of the tellurium below.

## 13 thoughts on “Laser Cutting Orreries”

1. whoah, that’s a lot of gears! The wobble is distracting but i’ve watched it a few times to see the phases of the moon and the seasons change. I can see myself doing this with half spheres and no automation just to play with it. Tack up post-its on the walls around me for the “fixed” stars and constellations.

1. SlowBro says:

What would prevent the wobble, how could that be fixed?

1. Andy says:

2. Dougmsbbs says:

I love it. Well, maybe not that jerky moon so much. Get that worked out and it would be great.

1. OLD_HACK says:

I am sure version 1.2 will use anti-backlash gears and some Teflon white-grease…
;-)

3. An orrery is a clockwork model of the solar system…

1. Daniel Abrams says:

I like the original definition better. A model of the solar system that was fixed and didn’t move wouldn’t be an orrery. The word clockwork implies motion coordinated in precise ratios.

4. Gravis says:

Hmm… is it weird that I haven’t noticed how our moon bounces around the sky? :-P

1. Als says:

That’s because you don’t drink enough alcohol.

5. notarealemail says:

Pitch Black had a interesting one.

6. echodelta says:

Like it or not we are all Tellurians.

7. moot-rasta says:

Anyone got any suggestions for good value acrylic laser cutting services in the UK (or with cheap postage to the UK)?

1. search for a local hacker space, they nearly always have a laser cutter.

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