Gert, There isn't much difference between the two to begin with but things like this can cause long lines of arguments so I am going to try to answer this without causing the argument to begin (my disclaimer as to this can of worms). :) Technicially, the F6 will give you a smaller image at prime focus. This image will also have more background light so that the photo's can't be taken for as long. The eyepieces, of course need to be of a shorter FL so that the same image scale is there and that means that the eye relief is shorter for a particular design series of eyepieces (disclaimer again!) :). On the other hand, the F6 will give you a larger field of view if allowed to do so by the main tube. Either one would do very nicely for almost anyone. If you get a bigger scope (in the 16" and up class) the F8 will do a better job in guiding with a CCD guider (They are a modern miracle for the photographer) so that is another point to ponder. Also is where is the eyepiece when looking at the zenith? If you can't reach it easily then It's the wrong scope. It's not hard to lean over a bit and lower objects tend to want a variable height chair to make viewing easy. Have Fun and Keep Looking Up. Bob May