Yep, spot on
Prime focus = using your telescope as the camera lens, while eyepiece projection uses your camera with it's lens to take an image at the eyepiece of a telescope.
Some digital SLR cameras are better than others though, and the Canon EOS digital SLR's are arguably the best digital camera out there when it comes to using them for astrophotography purposes. Some people do use Nikon digital SLR's though, and I have seen the other brands occasionaly used.