Quote Originally Posted by Poisson Du Jour View Post
Locate the Southern Cross. Next, place your thumb and index finger on the cross-beam (horizontal line of two stars that form the cross) and duplicate the length three times to the right. This approximates very closely the South Celestial Pole (which has the distinction of being around the 3,000th faintest star... ) around which all other stars rotate.
The closer you point the camera to the pole, either north or south, the more circular the star trails will be. The farther east or west you point, the more the trails will appear as arcs until, ultimately, if you point due east or due west, you'll see nearly straight lines, depending on your lattitude. If you point due east, the star trails will appear to rise. If you point due west, they'll appear to set.

You probably won't be able to tell "rising" from "setting" in the resulting picture but the point is to be able to look at the stars in the sky at the time you start taking the picture and predict which way the trails should lead when you're done.

This isn't an exact science. Just a few items to give you some idea of what to expect.