Slice I think that its a matter of focal length not focal ratio . The fact of the matter is that its easier to make a good long focal length lense or mirror and harder to make a good short focal length mirror or lense.
The focal ratio is determined by dividing the focal length in mm by the aperture in mm. e.g 2000mm(focal length) divided by 200mm(8"aperture) = f/10 as in a C8 sct. So Slice I think that faster ratio is really only a benefit for imaging, collecting more light quicker .
Now if I only understood what I just said !
Louie
