The Eclipses tellurium was the most complex of the different telluria that we did for the Griffith Observatory. Originally, we worked on a mechanical solution, which looked just like one of the 1800s devices with gears everywhere – but the client did not want a regular eclipse to happen every time in the same place; we decided to have a separate secondary motor to control the movement of the moon around the earth so that we could generate an interference pattern of not quite 12:1 between the rotation of the moon around the earth and the rotation of the earth around the sun, so as to simulate more random occurances of eclipses.

The sun has a very bright LED light built into some custom made optics to get a controlled beam size that just covers the area that it needs to. Again, we used our 3D printer to generate the earth and the moon, and the earth has a quality servo motor and servo controller built in. The top of the earth is a removable slice that locks into the main body to allow the earth to be located. The moon is then driven by the mechanism that runs out of the bottom of the earth.