I found a post from last March ('06) but it didn’t answer my question, so I thought I’d start a new post.
I’m in the process of building a variety of astronomy-related educational films. My current project is to show the Moon orbiting Earth, relating to eclipses and the phases of the Moon.
I’ve tried setting the Moon’s center at Earth’s center and using a z-rotation to produce orbital motion. However, the Moon’s orbit is not in the same plane as Earth’s so I’m trying to figure out how to tilt the Moon’s orbit. I can tilt the Earth and the child-Moon will follow. But Earth has a different tilt (23 degrees) than the Moon’s orbit (5 degrees) and in a different direction, so I’m not sure how to produce a tilted Moon and a tilted Earth. Any ideas?
Ideally, I’d like to use a path. This would allow elliptical orbits as well as allow non-uniform speeds. I know how to build an orbit path and get the Moon to follow the path. But I cannot figure out how to get the Moon (or any object) to follow a path repeatedly. Changing the pathlength doesn’t do what I want and I haven’t come up with other solutions. Any ideas?
Anyone else have any nifty ideas for building orbits?
Thanks a bunch. As always, you guys rock.