Planetary orrery planning.

[Adam Petersen]

Hi,

Has anyone here turned a planetary orrery lamp? I'm working on drawing up some rough plans for one. I'm picturing a base, a center pole, donuts for each planet with a heavy wire to support it out to its orbit. I also am planning to put a lamp up the center pole so the sun is a round bulb. The planets will each be turned balls, but I am thinking I'd have to have them hollow to keep the weight down and make it feel nicer. Has anyone done something like this and do you have any suggestions or advise for me? I think it is doable and my son is gonna love it if I can pull it off.

[Steve Peterson]

Google orrery lamp and you will find plenty of examples. The people that build orrerys appear to be a bunch of people that like to help others, similar to most of the people on this site.

Are you trying to make the planets move with reasonable accuracy? It sounds like a bit of metal work for the gearing. And a few sections of telescopic tubing to allow all of them to turn independently. It sounds like a fun project. Maybe it would be more metal working or clockmaking than woodworking.

Steve

[Adam Petersen]

No no, there will be no gear work or the like. Just going to let my son spin them by hand and set them by hand. More for show than anything. Maybe solar system lamp would be a better description.

[Tom Wilson66]

Sounds like a fun project. I think one thing to watch out for is you will need to keep the arms holding the worlds fairly short, or it could tip over if all the planets are in alignment on one side of the sun. This would require a heavy stand to handle the torque. Hollowing the planets, as you mentioned, will make a difference, also.
Are you going to add the two new planets the astronomers believe are out in the oort belt? And are you leaving out Pluto, which has been declared to not be a planet? The Solar System is changing fast these days, and your lamp may be dated before you get it done!

[Adam Petersen]

Good point on the tipping aspect Tom. I'll make sure to have a sizable, heavy base. Maybe I'll weight it with an internal piece of steel or shot so it doesn't get bulky and out of proportion. I'm going to keep Pluto as a planet. I've watched the debates that deGrasse held on Nova, and to me I still consider it a planet. Who knows how big our solar system really is? For the purpose of this though, I'm stopping at Pluto.

[Steve Peterson]

This is a woodworking forum, so I will suggest a mostly wooden option.

Start with a heavy wooden base with a heavy metal pipe supporting the sun. Stack 9 wooden donuts that are about 3" in diameter and 3/4" thick over the center pipe. Drill a hole in each donut to accept the support wires. You may need to fold over the end of the wire and use epoxy to glue in the wires so they won't spin. Glue the planets on the other end of the wire.

I would guess that something around 3/32" diameter music wire would be about the right stiffness for the support wires without being too bulky. Hobby shops should have 3' lengths for about $2 each. You need tempered wire so it is really stiff.

Earth's moon should spin around the earth. Other planets like Saturn and Jupiter could have static moons, essentially pea sized balls sticking out from the planets.

This sounds like a fun project.

Steve