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If you can't afford the AP, you may not be able to afford some of the other choices mentioned either.

Assuming budget is the issue, then probably the Intes Micro MK91 will be about the largest "affordable" MCT that can be somewhat easily found on the used market (I don't think they are made in serial production anymore). I have seen these sell from between $3500 and $4000 USD.

These have excellent optics.

APM lists Intes Micro - Alter M1015 for about $9200 Euros.

Not exactly sure what the appeal of this kind of scope would be. The size and weight make it almost an observatory type scope.

My guess is that the resason that these are so expensive is becuase the demand is so low that they are likely only made on demand.

And they are so highly specialized that most people would not want to spend that kind of money.

Especially when you can get a perfect 10" Newtonian for a fraction of the price that will do about as well on extended targets and offer a much wider true field.

But if it is a big MCT that you want, the MK 91 is about the most afforedable large aperture MCT that generally shows up on the used market at a "reasonable" price.

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I ground and polished a 10 inch Zerodur mirror which I still have and it is white. Not "honey colored" at all.

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You have the A-P Mak? And you find your C-11 comparable for what you are doing?

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Roland can make his own Maks. I don't know why he bought the optics from Aries. He said he had to refigure them anyways.

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* The A-P's permanently collimated (though I would take issue with the word "permanent" as there's no such thing ). Not so with the Tak.

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Since the permanent collimation of the AP is a result of the edges of the glass being precision polished to be exactly orthogonal to the optical axis and the tubes precision machined with the same goal, one would have to do some significant damage to the scope to knock it out of collimation. Matthias Wirth has made some permanently collimated Mak-Newts in a similar fashion.

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You guys have been posting quicker then I can read. Joe originally answer my question with he's personal insight into my scope arsenal. He knew I had a M250 and questioned why I would want another 10inch CAT of any sort. He is right in that respect. The M250 is a very good scope. Look numbers are all good to go by but all it is, is theoretical real world testing. Practically I would have to say that you would be hard pressed to see the differences with aging eyes. Im guessing thats why we use machines to show us what we cant see lol. I agree as well that the M210 is a different scope to the M250 and cant be compared.
In Eddgie defence I would have to say that a good quality mass produced large apeture(C14)will whip a 10inch weather its AP or Tak thats a fact Ive seen first hand. I asked the question out of curiosity to see whats available if you have missed out thats all but it seems that the thread has taken the nearest exit on it way to a different destination. In light of all the responses the thread will be a great lasting legacy guys of all our knowledge and input for the future generations, that what I love most about forums, so keep it coming.

Thx

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I've had many C14's and still have two. There is no doubt they struggle with temp throughout the night. The new edge HD have the most trouble as they cannot take advantage of things like the Lymax cooler. Even with a Lymax, I have to re-use it on occasion throughout the night depending on the temp shift. That, is an annoyance. While you can use the Starizona secondary replacement cooler on an Edge, (not sure they make it for the 14 yet) I'm not removing my secondary (again) in the middle of observing for a touch up.

The Mewlon 300 with it's removable cover and the CRS version with stabilizing built in fans makes it all go away. The Mewlon 300CRS is the best cooling and maintaining temp cat I've used. Three sensors - In tube, Out tube and on the mirror make that possible. There may be better, but not that I've used. So in the end, if you have a great scope (lets make a BIG assumption and say you have an awesome C14) you WILL get beat up by a Mewlon on many of the nights of your BEST seeing because of rapid changes in temp that the 14 just can't keep up with.. This is why many report the best views a SP's end up being a 300 Mewlon. Nothing to do with what you started with, just that the Mewlon 300 is a great finisher.

BTW my mirror is def Pyrex Tom.

Best, Joe

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jason, I seem to collect mounts. I love the engineering and precision of them. I love to test them, measure there performance like I do a fine refractor. Maybe that sounds a bit weird. But to me... I enjoy the mounts as much as the scopes.

JJK, So what are the main differences you see between the A-P Mak and Mewlon 300CRS? I think that is pertinent to this thread. You're in a very good position to judge. I think Tanveer also has the A-P Mak and the C-11. I'm interested in him qualifying the differences there as well. I can only compare the Mewlon to a TEC 8" F15. To me there is no comparison. The Mewlon outshines it. While the TEC 8 is wonderful, it lacks the PUNCH of the Mewlon 300. Clearly aperture is the reason. I will say, the TEC 8 is the finest in that aperture I've ever owned.

Joe

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Since the permanent collimation of the AP is a result of the edges of the glass being precision polished to be exactly orthogonal to the optical axis and the tubes precision machined with the same goal, one would have to do some significant damage to the scope to knock it out of collimation. Matthias Wirth has made some permanently collimated Mak-Newts in a similar fashion.

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I believe that “permanent collimation” in the case of AP and other Maks that use spot secondaries simply means that the spot secondary being part of the meniscus can not move independently so it remains permanently collimated.

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Actually it's both according to Roland. He said in part:

"The AP 10" Mak is permanently collimated and cannot get out of collimation because the secondary mirror is a spot on the corrector and cannot ever tilt with respect to the corrector. Both the corrector plate and mirror are accurately ground on the edges and on the back surface, to be exactly orthogonal to the optical axis. That way it does not have to rely on push-pull collimation adjustment to get the optical axis to line up with the mechanical axis."

To read his entire post for context:

Roland's post

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You have the A-P Mak? And you find your C-11 comparable for what you are doing?

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This isn't the first time I've heard of a C11Edge compared very favourably to a top-shelf 10". The other case I'm thinking of wasn't an A-P Mak, but rather another highly regarded 10" folded design.

The Edge's do seem to be consistently impressing people. I'm wondering if they aren't really any more special than any well made SCT, but just the removal of aberrations across the field makes them appear just so much better?

Clear skies,

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Sorry if I gave the wrong impression about owning an A-P Mak. I wish it were true . I was referring to my 178mm A-P refractor with respect to coma-correction but that was probably a non-sequitur in a conversation about compound scopes.

You could not expect the C11HD to match the A-P: the polish on the A-P is too smooth, the CO much too smaller, the thermal management much too better. But it does give my 7" refractor a run for its money. E.g., on the D-D the only difference you notice between the two is that the single diffraction rings in the C11HD seem brighter as would be expected from a scope having a CO.

There is something that I noticed: shine a super-bright flashlight at an A-P lens and you see nothing. Do this on a D & G lens and you see fine scratches. Do this on a pre-HD Celestron and you'll see (fine) swirls and scratches everywhere. Now we all know this is not supposed to affect the image at the eyepiece but I wonder if it's a reflection of the care taken by premium makers like A-P when polishing. And, oh, the C11HD shows nothing at all as well, not on the corrector and not on the primary. Zip, nada, zilch. The Tak TSC 225 I used to own was just as bad as my erstwhile C9.25 in this department. Again, this may not mean anything much, but I found it interesting.

Tanveer.

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Are you speaking from experience? Roland says otherwise and in fact the claim on the A-P site explicitly says this:

"Our computer polisher runs at a mere 200 RPM, and consistently produces 1/10 wave surfaces from start to finish."

Yes, this is true but only when an optician programs the polisher to correct for errors. The polisher can automatically get the wavefront down to about 1/4 wave and then the optician steps in and programs the polisher to correct for aberrations that he has identified through testing. This is the time consuming process because of the repeated testing involved and the time required to have the optic cool before each test. This process can take hours to days for each optic. As for the mass produced optics, the polisher can rapidly figure and mass produce mirrors in minutes down on average to about 1/4 wave. Perhaps with the optics now being produced overseas with their cheaper labor costs, Meade and Celestron can put more attention into each optic but in the past this was not the case.
Marj Christen did post that Roland had in some cases accomplished some final figuring the Alvin Clark way, by polishing the lens with his thumb. Something no machine could accomplish.

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