The way I read it, Eddgie's point was not that a C-11 is a replacement for the A-P MAK but rather he was questioning whether a Mewton ought to be considered as offering nearly the performance of the A-P MAK.
Thank you.. Yes, this is pretty much exactly what I was saying.
The fact that I used the 210 is simply because I have not seen a test of the 250.
Still, both are Mewlons, and it is to me reasonable to assume that Mewlons are not made to the exact same high qualiity standards of these other scopes. To see so many tests of one type Mewlon that were not above the .95 Strehl threshold makes one question if the quality of the Mewlon product range is not to the same standards as the refractors.
And still, there is the issue of the much larger central obstruction of the Mewlon along with the four vane spider. These are going to lower the contrast so that it is on the oder of a 31% obstruction.
These factors, as your rightly surmize, caused me to question whether the instrument was in the same class as the AP, INTES Micro, or TEC f/15 scopes, which almost always test at the upper limits of optical perfection, and when f/15, have much smaller central obtructions and no spider.
And I still make my strongest recommenation that the most reasonable alternative to an AP 10" MCT would be a Zambuto 10" f/6 mirror with an optimized (17%) secondary.
For a third of the price, someone could put together a scope like this that would deliever essentially the same on axis performance. You would sacrifice the wide field capablitly of an f/6 telescope, but if you wanted to match the f/15 MCT (which itself is a narrow field instrument) then this is a very practical compromise.
The OP wanted alternatives, and this one is not only the most cost effective, it is esentially equal in performance to the MCT.
None of these other scopes would match th e10" f/6 with optimized (17%) secondary.
Of the scopes mentioned, this is the only one that will be essentially on par with the AP 10".
But that doesn't really matter if the only thing the OP wants is a big MCT. If a big MCT is his heart's desire, the rest really doesn't matter at all.
If it were a 7" APO that the OP wanted, we could offer wide variety of telescopes that would outperform it on-axis, but that would not matter either.
If one has a desire for a specific type, all the talk here is wasted.
But the OP asked for alternatives, nd I offerend the Intes Micro MCTs (at $10,000 euros) and the far more cost effective 10" f/6 optomized Newtonian.
The bottom line here is that these MCTs have limited demand, and as such, are priced at an extreme premium price.
The OP doesn't want to pay that price, and he doesn't have to pay that price if all he wants is to dublicate the performance.
But he won't do that without some compromise elsewhere.