1” scopes, because they are all the same…
Far from correct. While a 1" f/6.3 scope would give the same brightness as an 8" f/6.3 scope, there would be a huge difference in how they would image.
The true field would be far larger in the 1" scope, but everything in the view would be far smaller.
The role of a telescope is to magnify the image. This is true both visually and photographicly.
While the brightness at the focal plane for these two scopes (1" and 8", both f/6.3) for extented objects is identical, the larger aperture in this case would give 8 times the image scale.
Objects that were simply smudges in the 1" scope would be large enough to see structure and detail in the 8" scope.
If they were all the same, Hubble would be an 80mm triplet APO (if you asked on the refractor forum
You pick the scope for the target. Small scopes are good for large targets and big scopes are good for small targets.
And scopes in between are good for a little of each.
This is why the large APO is so well respected as an astrograph. It provides surperb off axis illumition over a very large image circle, has high transmission, high contrast, and can be used with focal reducers and focal extenders to get a large variety of image scales.
And by the way.. I have a great paper written by Ken Hutchinsen that has ray traces for the C8, C9, C11, and C14. These ray traces show the illumination level for all these designs over different size image circles using both the redcuer and native configurations. It is an excellent paper, and if you would like a copy, PM me your email address and I will send it to you.
It does not cover the EdgeHD designs, but native they should be somewhat similar. The new Reducers though are far better than the old ones in terms of vignetting in the larger scopes.
One of the main compromises of the standard SCT design is th off axis illumination tradeoff.
Other scopes make even more extreme tradoffs. The Mak Newts have a field that is only fully illuminated over a tiny image cirlce and have illumiontion characteristics that make the SCT look great by comparison.
So, one has to pick one's poison, but if a very wide illuminated field with a large image scale is what you want, get a big astrograph. That is why people sell them.
Don't expect to see much detail in the Ring Nebula if you use a 1" scope.