How can I use Celestia to visualize this?

[skan]

Hello

I'd like to visualize by myself how is the angle at which we see a satellite at dawn, seen from different latitudes.
I mean, I need to place an Earth, a satellite, and the sun, and visualize the angle they form in 3D.
I'd need to trace Sun's rays (to check dawn condition) and project the satellite position on the Earth surface.
It would also be nice that the program could automatically place the bodies on the proper orbit according to gravity laws and speed.

How can I do it with Celestia?. Or what other application can I use?

regards