Greetings to the group! I would like to use Guide 9 to simulate comet or asteroid orbits in 3D using "add a trail". I think I know how to do this since I have worked with stereographic photographs for many years. What I do not know is how to select a location in Earth's orbit before and behind the planet in order to get a parallax. I'm also not sure what a good parallax distance should be. For photographic purposes, the separation of the lenses should be about 1/30 the distance to the nearest foreground object. I am thinking I could try viewing from a point in Sun orbit that is a week ahead of Earth and a week behind.

David Chandler's program Deep Space 3D used to do this type of projection beautifully in DOS, printing side-by-side charts that you could see in 3D by using the cross-eye viewing method. ( would probably change this to anaglyphic so I could use red/cyan viewers for group presentation with a video projector.

Bill, do you think this is something that could be added in a version update to Guide?

Thanks in advance.

Roger in Jacksonville, FL