Ecliptic vs. Equatorial Plane

[PSUPhysicsStudent]

I created a data file (*.xyz) for an asteroid with heliocentric coordinates. I wanted to take a small chunk of data and convert it to geocentric coordinates to see the path from earth's perspective. After changing the *.ssc file so the asteroid orbited the earth, i noticed that all the coordinates were now with respect to the equatorial plane and no longer the ecliptic. Is there an easy fix for this or am i doomed to spend the next hour or so with Euler's equation?

[Spaceman Spiff]

I take it you subtracted the Earth's heliocentric position from the asteroid's heliocentric position, and made the asteroid a moon of Earth?

Try cheating: make a tiny fake planet inside the Earth, one that has the same orbit ("customorbit" that is) but with zero obliquity. The equatorial plane of the fake planet should then coincide with the Earth's ecliptic. Make the radius small, say 1km, and don't bother with textures, etc, and make the asteroid the moon of the fake planet.

Problem solved?

Spiff.

[PSUPhysicsStudent]

Wonderful idea!!!

You were correct in what I was doing and your solution will work perfectly. It's so much easier than what I was doing just now--trying to find alpha and gamma for Euler's equation for 3D coordinate systems. UGH!

Thanks a million.........!