Telescope Reviews: Is an SCT a good all-rounder for visual + imaging?

As you have already surmized, but scopes are natively f/10 without a reducer and f/6.3 with a reducer.

For extended targets, brightness has nothing to do with aperture. It is totally a function of focal ratio and focal ratio alone, and this is true for both visual and imageing use.

For imaging an extented target, if you use the same camera at the same exposure in both scopes at f/10, you get the exact same brightness in each image. Same at f/6.3. For a given expousre time, the image will be just as bright in each scope.

For visual observing of extended objects (nebula, galaxies, and planets), if you have two f/10 telescopes and you use the same eyepeice in each, you get the same brightness as well. So, brigthness for extended targets is simply a function of focal ratio.

In the case of the C6, for whatever reason that only Celetron knows, they used a very small baffle, so this means thatwhen imageing you will get about the same size true field from it as you will get form a C8 before vignetting starts.

So, the C6 will give just as bright an image, but at a smaller image scale. No wider field though because of the vignetting imposed by the small primary baffle.

For visual use, you get more contrast and more angular resolving power, and better limiting magnitude (fainter stars visible in Globulars).

The C6 will on the other hand be lighter and easier to use for long exposures becasue it will make less demand on the mount.

My own recommendation would be for the C8 because in most things to do with telescope performance when used visually, a bigger aperture is generally a better aperture.

The C8 can give a field that is almost as wide and much better illuminated than a C6 when used visually. The C6 gains a lot of focal lenght when used with 2" diagonals, and will loose a lot of illumination at the edge of the field when used this way. The C8 can be used with eyepeices like a 35mm Panoptic and remain very well illuminated at the edge of the field makeing it (to me) a better wide field telescope.

And for planets and deep sky observing, the extra aperture allows for higher magnifications at the same brightness, which helps greatly in observing.

But a C8 weighs more, and there will be many people that say that the scope you use the most is the best scope (I personlly think bigger is just about always better, but that is me).

So, for exposure times, both will give about the same brightness and about the same well illuminated true field size, but the C8 will give a bigger image scale.

For visual, the C8 has the advantage of better resolving power, better contrast transfer, and a field that is more fully illuminated when using very low power wide field eyepeices. It will be better for just about all observing.

But it weighs more.

In my opinion, everyone should have a C8. The penalty in size and weight over a C6 is simply to small to me to be meaningful, though it is a factor when it comes to mount capacity for imageing.

People will think I am bashing the C6 though. I am not. For people with bigger scopes, the C6 can make a fine smaller scope.

But if I could only have one scope (and I do have a C5, a C8, a 6" APO, and a C14), it would be the C8..

LOL. Only kidding.. Dude.. It would be the C14.

By my C8 would be my second choice.

But seriously, if you can only have one or the other, my own suggestion for all of the requirments you have put forward would be a C8. It will be better at imageing and at visual use for the requirements you specified.

Again, I am not C6 bashing, but the C8 does everything as well or better than the C6 in a package that is only a bit bigger and a bit heavier. The C6 might make a great second scope, but for a primary scope, the C8 to me is about 72% better.