What was the big idea?
I first thought of making a crocodile mostly submerged in murky waters, its eyes tracking some annoying insect as it circled overhead. I couldn’t really build enthusiasm for that idea so I let it rest for a while. Then one day I bumped into “The trip to the moon” from George Méliès” on YouTube, as you do. After admiring the way the cast acted in 1902 (constantly waving their arms about, to remind the viewers that this is indeed a MOVING picture) I thought yes, that’ll do instead of a crocodile and set off for the workshop.
Making
The moon is round, so I needed a round 13 cm dia. front as well as some cogs to turn the eyes. To make the eyes rotate in the same direction I also needed one cog in between. The cogs each have 8 teeth with 11 mm tooth spacing.
I initially used 2 mm brass pins to get the spacing right between the cogs, so that they turn freely without jamming. Later on I put the eyes on 4 mm dowel and drilled the holes out to 4.5 mm.
I made a pinwheel with 25 x 3 mm dia. pins @ 8 mm spacing. This moves the rocket in orbit around the moon via a 2 mm bent brass rod..
On the back of the large pinwheel I glued a fourth cog. All four cogs are the same. The large pinwheel thus turns the eyes at the same angular speed as the rocket. A couple of washers help the cosmic mechanism to turn smoothly.
A smaller 8-pin wheel is turned by a crank to drive the large pinwheel.
I experimented with the position of the pinwheels until they engaged smoothly, without jamming.
The back is a 13 cm disc, like the front. The back is mounted vertically on a stand, which the front is not. Otherwise the rocket couldn’t fly around. The front is mounted onto the back via the 12 mm dia. dowel which also serves as the axle for the large pinwheel.
The eyes are the two halves of a 30 mm dia. wooden ball.
A couple of washers keep the swivelling smooth.
Painting
I had a go at painting some craters to make the plain disc more moonlike. That didn’t work very well at all, so I asked the Internet for a nice blue moon, printed it out at the right size and glued it in place. I don’t think that Monet would approve, but then again he didn’t have a colour printer.
Impressions
The eyes track the rocket extremely well. I don’t know why I was suprised about that but I was. The rocket does fly a bit too quickly, so I should have used a higher ratio between the two pinwheels. The moon does however look slightly worried, as if it is thinking about that painful crash into one eyeball over 100 years ago.
Images
Download images here https://www.wordwise.de/Mooning_Around_Archive.zip
Video
Link to video https://www.youtube.com/watch?v=hyxrKdfu5d8