Greg,
One thing to keep in mind is two scopes, same aperture but different focal ratios, at the same magnification the image will be just as bright. You may know this, but some people can confuse f/ratio as having some visual consequence. f/ratio only matters photographically.
Sure, you won't be able to drop the magnification to get the same wide field with an 8" f/13 Mak as with an 8" f/5 Newt, but it's not like you are looking through a house brick either. Same magnification and with same AFOV, same image brilliance. What can vary though is optical quality, regardless of whether it's a Newt, SCT or Mak, & yeah sure, throw in refractors too.
Wavy has mentioned a lot of the tech stuff around Maks. I'll just relate my visual experiences with Maks vs SCTs.
I had used SCT's for my lunar sketching for many years. I had thought my SCT's were pretty good, even if the assembly of one of them was so poor that the corrector plate was very distorted by a way over tightened retention ring (current SCT owners,
read this thread as it may affect your scope). I've since looked through Wavy's 9" Santel, and my 7" Intes Deluxe, and the difference is chalk and cheese. My Intes Mak, despite being an inch smaller in diameter, I can push it to 500X and I do not see image degradation, something I cannot do with my SCT and it is now of typical SCT optical quality. And a side-by-side comparison between the Mak and SCT, yes the image in the SCT is a little brighter because of the aperture difference, but the quality of the image, how fine the resolution is I can see in both scope, the difference in subtle contrast variations, and how stable the image is in both, the Intes tears shreds off the SCT. I ended up spending all my time with the Mak and the SCT just sat there, tracking, but with no one looking through it...
No matter the design of a scope, if optical quality is magnificent, then seeing conditions will be less detrimental for visual. If the optical quality is not there, then not all the photons will not be going where they should, so when seeing is not perfect, the photon distribution will be even more erratic, and the image instead of softly waving like a flag in a gentle breeze, will be scintillating/vibrating too making pushing high magnification difficult to impossible to use. But if the optics are schmick, then the image will just gently wave but high magnification will still be possible. This was one thing I came to find out when I tested 6 different Cats to find a new one. This pic below is of the final shoot out between the three shortlisted Cats, two SCT's and the Intes Mak.
Planets, particularly are sensitive to optical quality as it is not just about getting a sharp image, but contrast is often forgotten in the equation. Many of the details are either seen or lost as they are totally dependent on contrast. All the photons need to go where they should, as any stray photons will reduce contrast as well as resolution (coatings & baffling are not the only aspects affecting contrast).
DSO's. Nearly all my DSO experience with Cats has been under light polluted skies. You may think this is a disadvantage, but not really. Instead, it's meant that optical quality needs to be especially good in order to see the best image possible as contrast is the key. Get the optical quality right, and at the same magnification a Mak is good as the very best refractor and Newt around. Get the quality right, and it will mean seeing the skirt around the Homunculus Nebula or not in less than perfect seeing conditions at 200X.
Brands? Wavy has mentioned a few. There are not many Mak manufacturers, but all are boutique optics. Skywatcher though shouldn't be dismissed outright. Whoever it is that is making the 7" Maks for them is doing a stupendous job! They have been refining their manufacturing techniques over the years, and while their earlier Maks were
very good (I've looked through these and seen the Enke division through one!
), the current crop of 7" Maks are even better. Will other brands that are re-badged Synta scopes be just as good? I cannot say as I have not looked through them. Maybe yes, maybe no - and there is form on the "no" side of things. Saxon at one time offered an 8" Mak, and I only know of one in Western Australia. And the Meade one I suspect is of Synta origin or the same manufacturer as produces for Synta.
Aperture? 7" is currently the largest readily available today. Larger aperture Maks are very rare today. With Intes now ceasing commercial production, and the sets of large diameter optics available to the likes of APM quickly diminishing, large diameter Maks (over 7") are very difficult to come by new. But what size aperture? That's entirely up to you and how deep your pockets are.
Alex.