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Equipment Discussions >> Refractors

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mgwhittle
Pooh-Bah
*****

Reged: 08/24/11

Loc: Chattanooga, TN
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Mel M]
      #5568217 - 12/12/12 08:15 PM

Quote:

Quote:

If the cost, the mount or the size is not an issue, then, aperture for aperture, a refractor is best (within limits). If, however, any of these are an issue, you'll have to compromise. It's as simple as that, in my opinion.

Can you afford a 12" refractor? I can't. Can I afford a 12" newtonian? Yup! Are they equal? No, but there are worse alternatives: No scope at all!


Clear skies!
Thomas, Denmark




He has also said refractors larger than 7 or 8 inches have problems that make other options more attractive for visual use.




Problems such as?


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: JJK]
      #5568221 - 12/12/12 08:17 PM

Quote:

Quote:

Theres a reason D. Peach lugs those heavy C14s all the way to Barbados during opposition. For imaging the extra 4" will win.

As to the op, its a tough one. For imaging Id go with the AP, for visual, the TEC. Letting go of that TEC is dicey, 8" chunks of fluorite are going the way of the dodo.




He also doesn't have an AP Mak-Cass.




Very true but post imaging processing would fly right past the AP10 images. Oh I'm sure the 10mak is dandy and probably the best in the world and I believe other c14 owners who give the visual nod to that Mak. But being that processing can manipulate contrasts with extreme efficiency that little contrast edge the mak might have had is left behind as wavelet sharpening brings out micro details only a 14" can access through angular resolution. I would suggest perusing some of the 180mm AP APO planetary images and it's clear even a ten inch f/4 newt is outdoing it.

Which one would I owner though - money no object. It'd be the Mak hands down. The c14 has that angular edge to be sure but in terms of visual contrasts and an aperture less needy of seeing than the 14 and the ten is king. The eight - any eight by ANYBODY- will never outdo a ten inch aperture in imaging. Visually it might do better in lesser seeing but don't we observe for those better nights?

Pete


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Ziggy943
Post Laureate


Reged: 08/11/06

Loc: Utah
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: azure1961p]
      #5568235 - 12/12/12 08:31 PM

No doubt the AP 10" Mak is capable of superior performance on the Moon and planets over the TEC 200. Question is, in the field how often will that happen.

In my experience there are two components to the final "seeing." One is the atmosphere over which we have no control. The other is the thermal stabilization of the telescope. My experience with telescope thermal stability was with the 9" refractor an, by the time it was set up, it was ready to go. Not so with the 8" MAK. With very few exceptions it never reached equilibrium.

In my location it was my experience with a TEC 200 F/15 Mak that it reached it's planetary and double star potential 2 or 3 time in 4 years. Visually, side by side, the 160 class APO's outclassed it on Mars and double stars. That's why I made the decision to go with an APO refractor for myself. I'm not talking about just after set up, I mean for the observing session. My favorite double to judge the seeing is Epsilon Lyrae. I recall a friend shaking his head when looking through my 8" MAK. That hurt. OTOH, I had E-Lyrae at 400x in the MAK one night (literally one night) when seeing must have been perfect and had an image I can still see. On that night it was better than a 160 could be. Is that enough? It isn't for me.

I prefer the consistency of the refractor over the MAK in my location. If you live in an area where you have minimal nightime cooling the MAK may be a better choice.

When all is just right with the MAK it was the better scope but on run-of-the-mill nights the refractor is the better choice.


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Ziggy943]
      #5568434 - 12/12/12 11:08 PM

You don't now anything about the AP 10" Mak-Cass with your statements. Roland designed his 10" with a removable back cover exposing the primary mirror's backside, a primary mirror fan if needed, and a primary figured with aspheric curves for a flatter field and made of quartz. The two optical elements Mirror and corrector are 1/10 wave as is all of Roland's telescopes! Imagine that – 10 inches of 1/10th wave optics!! Who else is doing that? After the optics were bought from ARIES Optical, Roland was dissatisfied with their quality and totally refigured them to his high specs. Roland didn't make much money on these scopes after all of his extra work on them. Perhaps, this is why he dropped continuing the Mak-Cass production. This design quickens equilibration time and even allows great observing at moderate powers right after setting up outside before sunset. The 10" AP Mak-Cass is far superior in design to any other Cat. As you focus at any power. there is absolutely no mirror slop, either. Also, the Mak is not a reflector. It is a Cat.

Quote:

No doubt the AP 10" Mak is capable of superior performance on the Moon and planets over the TEC 200. Question is, in the field how often will that happen.

In my experience there are two components to the final "seeing." One is the atmosphere over which we have no control. The other is the thermal stabilization of the telescope. My experience with telescope thermal stability was with the 9" refractor an, by the time it was set up, it was ready to go. Not so with the 8" MAK. With very few exceptions it never reached equilibrium.

In my location it was my experience with a TEC 200 F/15 Mak that it reached it's planetary and double star potential 2 or 3 time in 4 years. Visually, side by side, the 160 class APO's outclassed it on Mars and double stars. That's why I made the decision to go with an APO refractor for myself. I'm not talking about just after set up, I mean for the observing session. My favorite double to judge the seeing is Epsilon Lyrae. I recall a friend shaking his head when looking through my 8" MAK. That hurt. OTOH, I had E-Lyrae at 400x in the MAK one night (literally one night) when seeing must have been perfect and had an image I can still see. On that night it was better than a 160 could be. Is that enough? It isn't for me.

I prefer the consistency of the refractor over the MAK in my location. If you live in an area where you have minimal nightime cooling the MAK may be a better choice.

When all is just right with the MAK it was the better scope but on run-of-the-mill nights the refractor is the better choice.




Edited by Peter Natscher (12/13/12 09:21 AM)


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JJK
Carpal Tunnel


Reged: 04/28/08

Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Peter Natscher]
      #5568505 - 12/13/12 12:06 AM

Quote:

You don't now anything about the AP 10" Mak-Cass with your statements. Roland designed his 10" with a removable back cover exposing the primary mirror's backside, a primary mirror fan if needed, and a primary figured with aspheric curves for a flatter field and made of quartz. The two optical elements Mirror and corrector are 1/10 wave as is all of Roland's telescopes! Imagine that – 10 inches of 1/10th wave optics!! Who else is doing that? After the optics were bought from AIRES Optical, Roland was dissatisfied with their quality and totally refigured them to his high specs. Roland didn't make much money on these scopes after all of his extra work on them. Perhaps, this is why he dropped continuing the Mak-Cass production. This design quickens equilibration time and even allows great observing at moderate powers right after setting up outside before sunset. The 10" AP Mak-Cass is far superior in design to any other Cat. As you focus at any power. there is absolutely no mirror slop, either. Also, the Mak is not a reflector. It is a Cat.

Quote:

No doubt the AP 10" Mak is capable of superior performance on the Moon and planets over the TEC 200. Question is, in the field how often will that happen.

In my experience there are two components to the final "seeing." One is the atmosphere over which we have no control. The other is the thermal stabilization of the telescope. My experience with telescope thermal stability was with the 9" refractor an, by the time it was set up, it was ready to go. Not so with the 8" MAK. With very few exceptions it never reached equilibrium.

In my location it was my experience with a TEC 200 F/15 Mak that it reached it's planetary and double star potential 2 or 3 time in 4 years. Visually, side by side, the 160 class APO's outclassed it on Mars and double stars. That's why I made the decision to go with an APO refractor for myself. I'm not talking about just after set up, I mean for the observing session. My favorite double to judge the seeing is Epsilon Lyrae. I recall a friend shaking his head when looking through my 8" MAK. That hurt. OTOH, I had E-Lyrae at 400x in the MAK one night (literally one night) when seeing must have been perfect and had an image I can still see. On that night it was better than a 160 could be. Is that enough? It isn't for me.

I prefer the consistency of the refractor over the MAK in my location. If you live in an area where you have minimal nightime cooling the MAK may be a better choice.

When all is just right with the MAK it was the better scope but on run-of-the-mill nights the refractor is the better choice.







I agree with Peter. The AP 10" Mak-Cass's thermal management and mirror shift are well executed.

In addition, its optics are impressive. The scope can be pushed productively to far greater magnification than any SCT with which I've observed.

Edited by JJK (12/13/12 12:07 AM)


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M13 Observer
scholastic sledgehammer


Reged: 12/09/06

Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: mgwhittle]
      #5568529 - 12/13/12 12:36 AM

Quote:

Quote:

Quote:

If the cost, the mount or the size is not an issue, then, aperture for aperture, a refractor is best (within limits). If, however, any of these are an issue, you'll have to compromise. It's as simple as that, in my opinion.

Can you afford a 12" refractor? I can't. Can I afford a 12" newtonian? Yup! Are they equal? No, but there are worse alternatives: No scope at all!


Clear skies!
Thomas, Denmark




He has also said refractors larger than 7 or 8 inches have problems that make other options more attractive for visual use.




Problems such as?




9 plus inch refractors become bloody big and heavy. Not too many people have adequate mounting to support them. Not too many people have the equipment available to move them. They require serious dedication to even house in an observatory large enough. There are a few people who manage to do so, but they are rare indeed.

A well executed 10" such as the AP Mak is a total lightweight in a short manageable package in comparison to the 10" AP refractor Clint(sp) has. I shudder with the thought of even moving the pier he uses, never mind that monster mount and OTA!


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Astrojensen
Post Laureate
*****

Reged: 10/05/08

Loc: Bornholm, Denmark
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: M13 Observer]
      #5568631 - 12/13/12 03:29 AM

Quote:

A well executed 10" such as the AP Mak is a total lightweight in a short manageable package in comparison to the 10" AP refractor Clint(sp) has. I shudder with the thought of even moving the pier he uses, never mind that monster mount and OTA!




Nevertheless, it's a dream of mine to one day own an 8" - 10" refractor (in a permanent observatory). A realistic dream, given my current income? No, but dreams are what they are.


Clear skies!
Thomas, Denmark


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RussD
member


Reged: 04/20/06

Loc: Minnesota
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: maknewtnut]
      #5569034 - 12/13/12 11:12 AM

Mark,
You are right.

After many years of looking through high end refractors was convinced that APOs were the ultimate planetary scopes. I still consistently see 5-6 apos outperform reflectors of almost any size at a typical star party. But good reflectors that are collimated well are still pretty rare around here. But once I had the chance to spend some time with a really fine reflector, mostly my Lockwood figured 10", I realized that I was wrong. In good seeing etc, I have seen it easily outperform 6 and 7 inch APOs in side by side views on Jupiter. Have not been able to do side by side with larger refractors.

Now I am convinced the biggest drawback of reflectors is cool down issues and air currents. Something that refractors seem to handle a little better. But once things are cooled and the seeing is good, aperture will win out.

Russ


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maknewtnut
Member
*****

Reged: 10/08/06

Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: RussD]
      #5569343 - 12/13/12 02:07 PM

Ziggy makes a good point too. Consistency in achieving potential performance may very be the most overlooked issue in scope selection (and discussion about it). One factor that often affects consistency is location. Those that live in high desert have to contend with far different ambient conditions than someone that lives on the coast. Detrimental effects from CO become exacerbated by less than ideal seeing conditions as well.


Case in point: all the folks who endlessly refer to Peach's planetary images as 'proof' of how good all C14's are.

There are too many factors to consider to lay down blanket statements.


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Ziggy943
Post Laureate


Reged: 08/11/06

Loc: Utah
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Peter Natscher]
      #5569371 - 12/13/12 02:21 PM

Peter, Your quote,

"Also, the Mak is not a reflector. It is a Cat."

Of course the Mak is a reflector. It has a primary mirror does it not? It's a more exotic reflector but it's still a reflector.


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TG
Pooh-Bah


Reged: 11/02/06

Loc: Latitude 47
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Peter Natscher]
      #5569372 - 12/13/12 02:22 PM

Quote:

The two optical elements Mirror and corrector are 1/10 wave as is all of Roland's telescopes! Imagine that – 10 inches of 1/10th wave optics!! Who else is doing that? After the optics were bought from ARIES Optical, Roland was dissatisfied with their quality and totally refigured them to his high specs. Roland didn't make much money on these scopes after all of his extra work on them. Perhaps, this is why he dropped continuing the Mak-Cass production.




The two optical elements have to be more than 1/10 wave corrected. 1/10 wave is what A-P guarantees is the wavefront quality at the eyepiece and being mirrors, both secondary and primary surfaces have to be figured to 1/20 wave. Roland's said he stopped making this design because it was a "female dog" to make with its aspheric curves.

While Roland put considerable thought into the cooling aspects of the scope, such as a rear-polished quartz primary, fans, removable backplate, etc., the fact remains that large scopes will have trouble catching up to ambient when it drops faster than the rate at which they can reasonably cool off. In the northern climes, especially when it's a bit dry, temperatures often keep dropping into the early morning. Any large scope, including the venerable A-P Mak, will have to wait till this time for optimum performance. FWIW, my 7" refractor performs optimally only at this time, not from its own cooldown problems but from the fact that the atmosphere had stabilized by then.

Tanveer.


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TG
Pooh-Bah


Reged: 11/02/06

Loc: Latitude 47
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: JimP]
      #5569376 - 12/13/12 02:26 PM

Quote:

Buying is not the question. Let's say neither would sell for more than the other. You walk into a store and can walk out with one, no charge. Which would it be?




Without busting a spinal disk I doubt any of us codgers could actually walk out of a store with a 200mm refractor.


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Bowmoreman
Clear enough skies
*****

Reged: 09/11/06

Loc: Bolton, MA
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: TG]
      #5569529 - 12/13/12 04:22 PM

My weigh-in, with not anywhere near enough "samples" (especially on nights with good enough seeing)... Rating Jupiter views:

1. 12" Takahashi DK (my neighbors) - revelatory views
2. Close 2nd - my 10" f4.7(ish) Zambuto mirrored Dob
3. My C11
4. My TOA130
5. My FSQ106

Note the *almost* perfect correlation to aperture... with the 10" Zambuto reflector clearly beating the 11" C11, likely due to a) quality of optics and b) rather smaller central obstruction

As I'm not - yet - a planetary imager (though my friend/neighbor with the Tak M300 *is*) I can't / won't comment on that aspect...

So... I'd have to vote for the AP Mak... especially on "practicality" grounds


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: TG]
      #5569563 - 12/13/12 04:43 PM

Also, the AP 10" Mak-Cass needs no collimation as other Cats and Cass'es do! – the secondary is not a separate mirror but a silvered area on the corrector (as Questars are).

Quote:

Quote:

The two optical elements Mirror and corrector are 1/10 wave as is all of Roland's telescopes! Imagine that – 10 inches of 1/10th wave optics!! Who else is doing that? After the optics were bought from ARIES Optical, Roland was dissatisfied with their quality and totally refigured them to his high specs. Roland didn't make much money on these scopes after all of his extra work on them. Perhaps, this is why he dropped continuing the Mak-Cass production.




The two optical elements have to be more than 1/10 wave corrected. 1/10 wave is what A-P guarantees is the wavefront quality at the eyepiece and being mirrors, both secondary and primary surfaces have to be figured to 1/20 wave. Roland's said he stopped making this design because it was a "female dog" to make with its aspheric curves.

While Roland put considerable thought into the cooling aspects of the scope, such as a rear-polished quartz primary, fans, removable backplate, etc., the fact remains that large scopes will have trouble catching up to ambient when it drops faster than the rate at which they can reasonably cool off. In the northern climes, especially when it's a bit dry, temperatures often keep dropping into the early morning. Any large scope, including the venerable A-P Mak, will have to wait till this time for optimum performance. FWIW, my 7" refractor performs optimally only at this time, not from its own cooldown problems but from the fact that the atmosphere had stabilized by then.

Tanveer.




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mark8888
Carpal Tunnel


Reged: 09/24/10

Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Peter Natscher]
      #5569790 - 12/13/12 07:24 PM

Peter, speaking of comparing large refractors and Maks, are you happy with your AP175, or is there something about it you wish were more AP Mak-like?

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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: mark8888]
      #5569872 - 12/13/12 08:16 PM

I haven't had enough observing time with my 175 yet to give a complete answer but right away, but the biggest difference between the two is the difference in focal lengths. The 10" Mak-Cass has over 3600mm focal length compared to 1400mm for the 175. That's over 100% more fl for the Mak. For planetary observing, this means you can use longer fl eyepieces with more eye relief without any or marginal amplification. The 10" with a ~3600mm native fl and Mark V bino using the 1.25X GPC gets 385X with a easy to look into 12mm eyepiece with generous eye relief. The 175 has a shorter 1400mm fl, less than 50% of the 10" Mak, so I'm constantly amplifying the eyepieces with 2X barlows or GPC's in the Mark V bino to approach 300X or more. I am already using the 2.6X GPC in the Mark V bino to bring its fl up to 3640mm and using two 11mm TV Plossels with shorter eye relief to get 330X on planets. The Mak is designed for high power but small field of view. The Mak is more specialized than the 175. I like the 175's versatility over a longer fl Mak design in that it can frame more deep sky objects using low to medium powers. Mechanically, I find the 175 very satisfying to use and its overall build feels to me superior to the Mak. In the future after Roland ceases to produce any more telescopes, I think he will most likely be remembered first for his triplet APO's over any of his other designs and I like the idea of owning and observing with one of these.

Quote:

Peter, speaking of comparing large refractors and Maks, are you happy with your AP175, or is there something about it you wish were more AP Mak-like?




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mark8888
Carpal Tunnel


Reged: 09/24/10

Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Peter Natscher]
      #5569933 - 12/13/12 08:46 PM

Thank you for your comprehensive thoughts! Very interesting comparison. It seems to me that... a refractor can do everything a Mak can do, but some things not as well (for example, achieve high mag as easily, and of course the size gets unmanageable with higher aperture), while a Mak simply cannot achieve as a wide a field as refractor can... so it kind of makes a refractor more essential to have as a scope, unless you really aren't interested in wide fields. Of course, as is pointed out so often, one can have more than one scope... your post makes it very clear why that might be a good idea.

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Tom and Beth
Post Laureate


Reged: 01/08/07

Loc: Tucson, AZ
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: maknewtnut]
      #5570072 - 12/13/12 10:30 PM

Quote:

Ziggy makes a good point too. Consistency in achieving potential performance may very be the most overlooked issue in scope selection (and discussion about it). One factor that often affects consistency is location. Those that live in high desert have to contend with far different ambient conditions than someone that lives on the coast. Detrimental effects from CO become exacerbated by less than ideal seeing conditions as well.


Case in point: all the folks who endlessly refer to Peach's planetary images as 'proof' of how good all C14's are.

There are too many factors to consider to lay down blanket statements.




Good points, Mark. And recently Damian produced some jaw dropping shots with the AP 10" Mak.

Edit: to avoid injury, sit down

Here is a movie Damian Peach made using my telescopes while visiting recently.
The images used to make the movie were made primarily with an AP 10" F/14.6
Maksutov. One image was made with a TMB 10" F/9 apo. See below FYI.

Jim Phillips

http://www.damianpeach.com/jup1213/oct2012whole.wmv




Edited by Tom and Beth (12/13/12 10:47 PM)


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Tom and Beth
Post Laureate


Reged: 01/08/07

Loc: Tucson, AZ
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: mark8888]
      #5570087 - 12/13/12 10:36 PM Attachment (61 downloads)

Quote:

Thank you for your comprehensive thoughts! Very interesting comparison. It seems to me that... a refractor can do everything a Mak can do, but some things not as well (for example, achieve high mag as easily, and of course the size gets unmanageable with higher aperture), while a Mak simply cannot achieve as a wide a field as refractor can... so it kind of makes a refractor more essential to have as a scope, unless you really aren't interested in wide fields. Of course, as is pointed out so often, one can have more than one scope... your post makes it very clear why that might be a good idea.




OK, but who says you can't have both? This is a REALLY lousy pic taken with the Security Cam, but you get the idea.


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Bowmoreman
Clear enough skies
*****

Reged: 09/11/06

Loc: Bolton, MA
Re: AP 10" Maksutov vs TEC 200 Fluorite apo new [Re: Tom and Beth]
      #5571212 - 12/14/12 05:35 PM

Lordy, but the word jealous just doesn't even begin to come close!



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