Yes, ED80 has higher f-ratio, but shorter focal length, which is what determines the true field of view for photography. Though it is not that much shorter at 600mm than the 8" f4 at 800mm. But no coma, so quite a bit larger usable field I'd expect.
But maybe the new Saxon EDSP 80mm is what you need, Eric. It looks like it is shorter than the older style ED80, and has a much better focuser.
