Mechanical Planetarium

[Update, 12/16/2020: Thanks for all the kind comments. Some people have had trouble with gear meshing, and various improvements have been proposed and posted elsewhere. I appreciate the efforts others have made. Mine still works fine for me, but as with all designs your mileage may vary. I've just added a photo of the planetarium advanced to today's date, after not touching it for 2 months. Gratifyingly, it clearly shows the conjunction of Saturn and Jupiter, as well as how they are only visible near sunset given the low angle with respect to the sun. Mars is falling behind Earth as expected, from its position of minimum distance in October 2020.]

*Original Text*
A working planetarium*, modelling the orbits of the inner 6 planets and the Moon. One rotation of the dial equals 14 days of movement.

https://youtu.be/AKBxbvwoRgs

Accuracy (orbital period in Earth days, actual / model)
Mercury 87.97 / 86.31
Venus 224.70 / 224.87
Earth 365.26 / 365.26
Mars 686.98 / 688.65
J