To use an SCT, you would need a full aperture D-ERF to handle the thermal load. This will cost minimum $2k, plus another few hundred for a holding cell to mount the D-ERF. The Quark's specifications for 80mm aperture or more is only applied to refractors; not to folded optic designs like SCT. You need full aperture for SCT, Newtonian, etc, for a D-ERF, which means huge costs. A D-ERF is very much a narrowband filter (dielectric at best), so you know at 8" it will cost you not only premium but custom costs.
Your 127mm refractor will work with a Quark without anything special beyond a basic UV/IR block filter in front of the Quark. This is more realistic. It is still subject to seeing limitations.
Seeing conditions during the day, need to be sub-arc-second seeing to try to realize the resolution of 200mm during the day. So unless you're in a very special geographic place on Earth where seeing is less than 1 arc-second sustained per minute, do not bother with 8" or greater apertures for day time solar imaging. I say this as someone who experiences this in Florida and I have an SSM monitor to get measurements. I also have a C8 Edge, D-ERF and Quark setup that I've imaged with. It's not as simple as just buying the equipment. You must have excellent seeing conditions to realize the resolution. There's no magic bullet to this, you must have sub-arc-second seeing conditions to image with 8" aperture at critical sampling for solar during day time. Otherwise, you might as well use smaller aperture. There's no way around this.
I cannot stress enough, do not think its a matter of getting the gear. The seeing is what matters. Day time seeing is way, way, way worse than night time seeing. You will find for your area, there is a specific time of day that seeing is ideal. You can only attempt high res imaging then. Even then, it better be sub-arc-second sustained per minute, or you will not get 200mm aperture resolution potential.
The Quark has an internal 4.3x telecentric amp. Use that to figure your focal-ratio and effective focal length. Now consider your 224MC sensor's 3.75um pixels. You will be using a 0.5 focal reducer most likely to get things more reasonable for sampling at those image scales.
Your refactor is much more likely to be a successful option for imaging like this.
Here's a place to get an idea of your seeing conditions: https://www.meteoblu...merica_11395215
Plug in your location. Maine is not known to have great seeing. 2" seeing is not going to support 8" aperture. That's 102~127mm aperture at best based on conditions.
Here's my C8 Edge, plus a full aperture D-ERF (Aries) in a T.S. made cell holding mount with my Quark, along with 0.3"/pixel image scale captures I've done recently (spring of 2019):
This is not the results you can get from 1.5~2 arc-second seeing. This requires 0.7~1 arc-second minimum, sustained, seeing during the day. This is with the exact system you propose. This is only an option for a very few places on Earth honestly.
That said, let's look at what you can do with a mere 120mm aperture refractor, an achromatic, not even an ED doublet or more, with a Quark. No expensive D-ERF needed, just the internal UV/IR block filter in front of it, under ok seeing conditions (2~3 arc-second conditions):
120mm frac with Quark (no big front mounted full aperture D-ERF; Celestron Omni XLT 120mm F8.3 achromatic doublet + Quark):
Edited by MalVeauX, 27 February 2020 - 10:37 PM.