Hello Rodger,
Before you mount the 350 to the 'scope you need to determine if there is enough back focus so that the you can at least focus the image. Many newtonians are not made for astrophotography. Matching the camera to the scope will require a standard T coupling.
The 350D has a reasonably large CMOS sensor so you will need to determine if the field is reasonably flat to do this camera justice.
What is the focal length of the 'scope? Given this number we can work out the image scale and field of view then take it from there.
Rgds,
Jerry.
