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Apos better than Newts?

ATM reflector refractor
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#376 tomjones

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Posted 04 November 2015 - 04:08 PM

Had an 8" f/7 Optical Craftsman 1/8 wave ota, did all the right stuff- short focuser, 3 vane spider, tiny secondary and thought it was swell.

 

Then bought a banged up Antares 8" f/5 that had been changed for photos- main mirror moved up to reach camera focus, larger secondary, average height focuser, but the key piece- mirror refigured to 1/14 wave, came with papers.

 

The Antares was much better on the planets than the OC f/7.  On Mars last year it even matched the APM 6"edapo lens had on a C6R tube.

 

The conclusion of this story- nothing matters but the optical quality of the main mirror.


 

#377 Astrojensen

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Posted 04 November 2015 - 04:09 PM

Isn't making a mak-newt in order to get rid of some coma a bit of overengineering at f/8? I see VERY little coma in my 6" f/8 newtonian, even in a 2" 30mm ES82 eyepiece. It's no doubt there, but there's not a lot of it. 

 

 

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#378 KaStern

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Posted 04 November 2015 - 05:28 PM

Hello Ed,

 

the central obstruction of the Mak-Newt does not need to be significantly bigger than that of the newt.

Only a tiny bit, because the Mak-corrector diverts the light on the way to the primary mirror

and the primary has to be a bit bigger.

O.K., I agree to Astrojensen, the coma of the 6"f/8 is not severe.

With my 8"f/6 I would like to have coma-correction.

I can use one of my 2.2x and 2.8x coma-compensating U.O. Klee Barlows,

but these are for higher magnifications, not for low power views.

 

Hello tomjones, I think the secondary is important too.

My original 50mm GSO secondary was not diffraction limited.

I replaced it with a smaller 39mm secondary wich is superb, tested with 0.98 strehl. 

It gave my newt a big improvement for planetary viewing!

 

Cheers, Karsten


 

#379 ed_turco

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Posted 05 November 2015 - 06:12 PM

Karsten,

 

I agree that at f/6, there still needs to have a tiny bit of coma cleaned up, but I'm not paying big money for a coma corrector for that little bit of coma.

 

I also it would be nice to have a Mak lens do some work, but do you know about the magnitude of such a project  and its cost?  A 6" Mak lens blank could easily set you back $500 because that glass has to be thick enough to hold those very steep curves!

 

Since Bob Cox and Alan Macintosh passed away, I haven't heard of anyone making their own Mak telescopes.  These thoughts came to mind when I was starting to put something together and a window was so much easier that I didn't feel that I had any other choice.   I wanted to demonstrate a telescope project that could be built by just about any ATM with a little experience; no one at that level would ever dream about a Mak except to buy one.

 

 

 

ed


 

#380 olivdeso

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Posted 21 November 2015 - 12:14 AM

That depends...which Newtonians...which APOs...and for what? ;)

+1

- the refractor is closed -> less tube current
- the refractir does not have any obstruction -> higher contrast, better FTM in medium frequencies
- the refractor has some chromatism/spherochromatism, the newton does not
- the refractor has a much larger illuminated field compared to common newtonian. The Newtonian requires a very large secondary to compete, which significantly impacts the contrast in visual use. At higher obstruction than 20%, the difference becomes obvious in visual use.

There are so many use cases...in some the refractor is prefered in some others the Newtonian better performs...

Its like comparing two different wrenches of the same size.
A flat open end wrench and a L shaped socket wrench for instance.
Both can do the job most of the time, but sometime one is prefered or even is the only way to do the job.
 

#381 ed_turco

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Posted 21 November 2015 - 12:30 PM

 

That depends...which Newtonians...which APOs...and for what? ;)

+1

- the refractor is closed -> less tube current
- the refractir does not have any obstruction -> higher contrast, better FTM in medium frequencies
- the refractor has some chromatism/spherochromatism, the newton does not
- the refractor has a much larger illuminated field compared to common newtonian. The Newtonian requires a very large secondary to compete, which significantly impacts the contrast in visual use. At higher obstruction than 20%, the difference becomes obvious in visual use.

There are so many use cases...in some the refractor is prefered in some others the Newtonian better performs...

Its like comparing two different wrenches of the same size.
A flat open end wrench and a L shaped socket wrench for instance.
Both can do the job most of the time, but sometime one is prefered or even is the only way to do the job.

 

From what I can gather from your views, you didn't read my article, listed below in red, followed by the flowered smiley, signifying peace.

 

I addressed  central obstruction issues and demonstrated that, according to Richard Suiter. that anything below 18% central obstruction is imperceptible to the human eye.  While there may be 10% of folks out there who might see that difference, the advertisers like to leave the impression that you are in that 10% and should buy an apo telescope.  And if you wish to argue the point with Richard Suiter who set that 18% criterion, you go right ahead; I have his email if you want it as long as you promise to post his reply.  I can't wait!  If you don't really believe him, I can quote from another source that some very well-known and erudite optical people who set that figure as high as 30%, while only one sets the numbers as low as 10%, so go figure.

 

You are to be commended for acknowledging the apo problem of spherochromatic errors.  These are more important that others, less fair than you, wish to admit.

 

As for wider fields, you have me, but with this provison; most if not all apos are almost, but not quite, apochromatic at the center of their fields; that spherochromatic stuff messes images up away from that center.  Indeed, the scientist Abbe came up with the first criterion for a lens to be an apo; that is first: it will bring three widely spaced colors to a color free central image free of spherical aberration and second, it will be corrected for coma in only one color.  So, once again, go figure.  As Abbe was the first to work this optical problem out, perhaps apos should be called "Abbe" telescopes, and you can use a capital letter.  So there you go :)

 

Please note that my article demonstrated that in the formation of the Abbe Disk, there was no perceptable difference between a Newtonian reflector and an apo of equal aperture.  That's right, equal.

 

Speaking of spider diffraction, there is none in the reflector that I described and built, not because I took the easy and fallacious way out with a spider that spread around that diffraction; instead, I made an optical window to seal my tube and hold my diagonal.  There were other things that I did, even considering the quality of polish in my telescope's optics.  Indeed, I even considered other deficiencies in both the apo and the Newtonian and fixed them in my Definitive Newtonian, issues that can never be addressed by an apo maker who knows the value of time and cannot waste any.  I can understand that.  To make a fair profit, he has to be this way.  Otherwise, his employees don't eat, pure and simple.

 

So there you have it.  Please read what I wrote and remember, I really did the research and even more since!  I can forgive you as you jumped into a discussion on page 16 derived from the substance of my article, "The Definitive Newtonian Reflector" and didn't realize what you jumped into. 

 

In passing, please do not capitalize apo; there was no person named "apo" who invented the design, and using capitals implies an importance not earned; an apo is just another optical design.

 

 

 

ed     :flowerred:


 

#382 photiost

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Posted 29 November 2015 - 09:26 AM

This is a never ending debate with passionate arguments from both sides.

 

I own both Apos + newtonians and enjoy them tremendously.

 

My only comments on this topic is that Newtonians are "natural" Apo's.

 

Not 99% or 99.99999% but Naturally Perfect Apo's . :cool: 


 

#383 ed_turco

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Posted 29 November 2015 - 10:22 AM

It bothered me very much that this was a never ending debate.  You'd think, seeing that this is wholly scientific debate, that some conclusions could be drawn by this time.  This is why I wrote a scientific paper, and if I had a PhD after my name, I could have gone almost anywhere among the optical journals and state my case.  Alas, I have only two Master's degrees, in English and math so it was no go for me.  However, CN very kindly accepted my work so it could get a showing and create interest.  At the time, I stated that seeing I had done the research, wrote the paper and built the telescope, that anyone else on the other side of the question could do the same and prove me wrong.

 

I am still waiting.  I know these things take time and that such articles demand a scientific rigor not found in amateur circles, but I thought that someone, out there, would rise to the occasion.

 

They haven't.

 

Furthermore if I try to instruct those in other CN venues  about these matters, others have complained about my tone,  my condecension and my not playing well with others in refusing to agree with someone who has no facts of the matter to report. So  I can hardly say anything at all.   This is not a debate of scientific issues, this is closing a debate by preventing an opposing party from coming to the table.

 

 

ed

 

 

 

 

ed

This is a never ending debate with passionate arguments from both sides.

 

I own both Apos + newtonians and enjoy them tremendously.

 

My only comments on this topic is that Newtonians are "natural" Apo's.

 

Not 99% or 99.99999% but Naturally Perfect Apo's . :cool:


 

#384 Asbytec

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Posted 01 December 2015 - 10:02 AM


This is a never ending debate with passionate arguments from both sides.

 

I own both Apos + newtonians and enjoy them tremendously.

 

My only comments on this topic is that Newtonians are "natural" Apo's.

 

Not 99% or 99.99999% but Naturally Perfect Apo's . :cool:

 

 

And a good parabolic mirror has the best figure for parallel light waves from optically infinite distant objects. The obstruction has some effect, but so does residual spherical aberration. 


Edited by Asbytec, 01 December 2015 - 10:03 AM.

 

#385 Bill Llano

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Posted 20 December 2015 - 01:20 PM

If they are of equal size, I will take the APO every time!  But the truth of the matter is that you can't say that a 6" APO can beat my 15" DOB. The light gathering capability alone of my OMI mirror alone will give you a much better and pleasing view. The rule that I use is: You get what you pay for but SIZE DOES MATTER!


 

#386 ed_turco

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Posted 21 December 2015 - 12:50 PM

If they are of equal size, I will take the APO every time!  But the truth of the matter is that you can't say that a 6" APO can beat my 15" DOB. The light gathering capability alone of my OMI mirror alone will give you a much better and pleasing view. The rule that I use is: You get what you pay for but SIZE DOES MATTER!

I never made any claims about differences in aperture.  What I proved; that there was no perceptible difference between  an apo and a well constructed  Definitive Newtonian of equal aperture.  What I did was to go after every defect known to plague Newtonians and deal with them using telescope making skills --

 

I even dealt with the quality of polish, for goodness sake, and if you think doesn't matter get a MTF graph for any telescopes with rough polish and you'll see what I mean. (Did it dawn on anyone else that Suiter's book is not only a manual for star testing a telescope but also a manual on what errors an enterprising ATM could work on and reduce to an insignificant level?)

 

Suiter demonstrates that any error can reduce the performance of even a telescope of perfect accuracy to one with a 1/4 wave error; dirty optics are an obvious example -- the MTF graph of these are a real hoot.  A much better example is the quality of polish, what we call primary and secondary ripple.  These can be avoided with the judicious control of the speed at which the polishing takes place.  Also, the use of rouge to minimize secondary ripple down to the level of Angstroms, (See Texereau) is a real improvement.  Do you think that the makers of commercial apos have the time to deal with all this?  I can see their point; machines polishing takes minimal time, and time is money.  Remember this, apo makers have huge startup costs with any lens they make; the glass they use is astronomical in price (pun not intended) so they need efficiencies in other areas.  My definitive Newtonian as no such costs and can be built by even a very moderately experienced telescope maker.

 

And that is a very big deal.

 

As an aside, you are right about size  in one sense.  It would be quite an awful 15" that couldn't outperform an apo of 3".  Go where the apo owners hang out and listen to how their 3 or 4" apo is the best thing in the Universe and hear how a 3 or 4" Newtonian is dinky.  Go figure.  

 

Also please remember, it does not need to be that famous "1 or 2 inch of extra aperture" for a Newtonian to equal a lesser aperture apo.  It doesn't have to be this way.  In the case of the Definitive Newtonian, "Equality of size matters."

 

 

ed


Edited by ed_turco, 22 December 2015 - 12:58 PM.

 

#387 Daniel Mounsey

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Posted 25 December 2015 - 02:24 PM

If they are of equal size, I will take the APO every time!  But the truth of the matter is that you can't say that a 6" APO can beat my 15" DOB. The light gathering capability alone of my OMI mirror alone will give you a much better and pleasing view. The rule that I use is: You get what you pay for but SIZE DOES MATTER!

 

An out of date perspective.


 

#388 ed_turco

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Posted 26 December 2015 - 04:24 PM

Daniel,

 

Thank you.   I really wish folks would quit comparing telescopes of unequal size.  As I said before, even a poor 12" Newt is going to outperform a 4" apo.  Anything poorer and the telescope would find it difficult to perform at all.   A description of such performance brings to mind something that I heard at Stellafane as an insult directed at such a poor Newt -- "It reflects light."

 

It is exactly this comparison that clouds the issue about the performance between one telescope and another.   It was this issue that caused me to consider researching my piece, comparing telescopes of equal size.  This method is so obvious; I cannot see how other well-intentioned observers of telescopic images repeatedly missed this point.  I still see this misperception being bandied about even today.

 

But there it is.

 

 

ed


Edited by ed_turco, 26 December 2015 - 04:28 PM.

 

#389 Asbytec

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Posted 26 December 2015 - 08:58 PM

It seems to boil down to one basic concept, which design can pack the most light into the central disc and minimize the brightness of the rings providing a favorable intensity distribution on the focal plane in the real world. Doing so is affected primarily by aberration, including seeing and thermally induced, and the obstruction or lack thereof.

 

Minimize both aberration, including polychromatic effects and micro ripple, and the obstruction and you can achieve images that are indistinguishable from one another. The refractor benefits with no added diffraction spread into the rings and operate near it's Strehl (ignoring chromatic effects.) A minimal obstruction will diffract some light into the rings, but at some point the intensity distribution is essentially the same to the human eye.

 

Both scopes have to be thermally stable. Deploy them in 8/10 seeing (actually any level of seeing provided it's the same for both equal apertures), and I believe the difference is indistinguishable. Whether it's reflected or refracted light, I am not sure if there is a noticeable difference in light loss through either. Nor is there any mention of a magical quality of one over the other. 

 

Refractors may reach this level of ambient performance easier, but maybe not because the heavy lens has to cool in the same way the primary mirror must. The trick is to allow them to stabilize in whatever climate allowing the optical figure to form and any boundary layer to dissipate. My own obstructed, mass produced CAT may not have the best intensity distribution, but the views are fine. It is thermally always stable and collimated. That is important, and more so the seeing. 

 

In fact, I'd rather have  a mass produced scope in good seeing than a premium scope in lesser seeing. Good seeing will see more and have better contrast transfer and resolution the /same/ aperture is capable of. Comparing scopes in different states of thermal equilibrium and seeing is not a comparison of scopes. It is a comparison of climate.

 

Bottom line, if one can achieve favorable intensity distributions in either design given the obstruction effects and polychromatic Strehl, the views /should/ be the same under the same observing conditions. In my experience, ~80% of the light in the central disc is nothing to sneeze at. But, better is better. And at some point "better" is indistinguishable from "better." 

 

Recently discussing views of the lunar limb, one refractor enthusiast was discussing the minimal fringing on the moon and how it was not objectionable. I agreed and admitted to seeing a minimal diffraction effect on the moon and how that was, also, not objectionable. They are seen in such good seeing, and washed out otherwise, that the very sharp view of the moon simply negated any concern over diffraction or fringing.

 

The moon was simply stunning that night regardless of performance measures and the type of scope. We put all of that aside and simply enjoyed the excellent images courtesy of a calm atmosphere. I'd say our views were essentially indistinguishable in the sense that we both got a real kick out of them. My larger aperture may have had an edge in resolution, but so what. That is not a comparison of equal apertures. It is a comparison of two wonderful images and our enjoyment of them. 


Edited by Asbytec, 26 December 2015 - 09:05 PM.

 

#390 bsavoie

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Posted 28 December 2015 - 05:35 PM

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor. Not quite sure exactly what the equation would look like, but it could be crunched from a view the Hubble took in a comparison with a photo of that same location in space from a telescope under study. Also part of this would an apparent field of view. Not too good to have a great picture of a very small star, I want to be drunk on the beauty of the field, filling up my soul, if I can be so bold as to state it that way. I think, since it is my equation, the field of view should be at least a thousand stars.

 

The numbers would represent any positional errors in the stars, any wave like errors, or loss of dynamic range in the picture. How many pixels. In short, how close does the scope come to a space based 21 ton 'cost is no limit telescope'?

 

Then I would like to see, this test done for many different types and sizes of telescopes, so we could look at the cost factors involved. Where is the value? Which scope is most like Hubble, and still within our pocket books?

 

I think math can be used to achieve a bliss view, wild beyond our current languages can develop using intellectual concepts. I think we need more math, and that math is part of the astronomy as a field of science. Otherwise we just go around and around. How about measuring something, and doing the hard work of learning more?

 

Bill Savoie (stirring the pot).


 

#391 Asbytec

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Posted 29 December 2015 - 08:26 AM

I am an observer, first and foremost, with an interest in why telescopes can put us soul stirring images. So, let Ss be the soul stirring factor, then Ss = Definitive Newtonian? Then what are the DNT properties making it soul stirring? Well, we wind right back at the initial equations that describe aberration, diffraction, seeing, tube currents, etc. These are the factors Ed applied to build it in the first place. 


 

#392 ed_turco

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Posted 29 December 2015 - 10:09 AM

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor. Not quite sure exactly what the equation would look like, but it could be crunched from a view the Hubble took in a comparison with a photo of that same location in space from a telescope under study. Also part of this would an apparent field of view. Not too good to have a great picture of a very small star, I want to be drunk on the beauty of the field, filling up my soul, if I can be so bold as to state it that way. I think, since it is my equation, the field of view should be at least a thousand stars.

 

The numbers would represent any positional errors in the stars, any wave like errors, or loss of dynamic range in the picture. How many pixels. In short, how close does the scope come to a space based 21 ton 'cost is no limit telescope'?

 

Then I would like to see, this test done for many different types and sizes of telescopes, so we could look at the cost factors involved. Where is the value? Which scope is most like Hubble, and still within our pocket books?

 

I think math can be used to achieve a bliss view, wild beyond our current languages can develop using intellectual concepts. I think we need more math, and that math is part of the astronomy as a field of science. Otherwise we just go around and around. How about measuring something, and doing the hard work of learning more?

 

Bill Savoie (stirring the pot).

 

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor. Not quite sure exactly what the equation would look like, but it could be crunched from a view the Hubble took in a comparison with a photo of that same location in space from a telescope under study. Also part of this would an apparent field of view. Not too good to have a great picture of a very small star, I want to be drunk on the beauty of the field, filling up my soul, if I can be so bold as to state it that way. I think, since it is my equation, the field of view should be at least a thousand stars.

 

The numbers would represent any positional errors in the stars, any wave like errors, or loss of dynamic range in the picture. How many pixels. In short, how close does the scope come to a space based 21 ton 'cost is no limit telescope'?

 

Then I would like to see, this test done for many different types and sizes of telescopes, so we could look at the cost factors involved. Where is the value? Which scope is most like Hubble, and still within our pocket books?

 

I think math can be used to achieve a bliss view, wild beyond our current languages can develop using intellectual concepts. I think we need more math, and that math is part of the astronomy as a field of science. Otherwise we just go around and around. How about measuring something, and doing the hard work of learning more?

 

Bill Savoie (stirring the pot).

 

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor. Not quite sure exactly what the equation would look like, but it could be crunched from a view the Hubble took in a comparison with a photo of that same location in space from a telescope under study. Also part of this would an apparent field of view. Not too good to have a great picture of a very small star, I want to be drunk on the beauty of the field, filling up my soul, if I can be so bold as to state it that way. I think, since it is my equation, the field of view should be at least a thousand stars.

 

The numbers would represent any positional errors in the stars, any wave like errors, or loss of dynamic range in the picture. How many pixels. In short, how close does the scope come to a space based 21 ton 'cost is no limit telescope'?

 

Then I would like to see, this test done for many different types and sizes of telescopes, so we could look at the cost factors involved. Where is the value? Which scope is most like Hubble, and still within our pocket books?

 

I think math can be used to achieve a bliss view, wild beyond our current languages can develop using intellectual concepts. I think we need more math, and that math is part of the astronomy as a field of science. Otherwise we just go around and around. How about measuring something, and doing the hard work of learning more?

 

Bill Savoie (stirring the pot).

 

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor. Not quite sure exactly what the equation would look like, but it could be crunched from a view the Hubble took in a comparison with a photo of that same location in space from a telescope under study. Also part of this would an apparent field of view. Not too good to have a great picture of a very small star, I want to be drunk on the beauty of the field, filling up my soul, if I can be so bold as to state it that way. I think, since it is my equation, the field of view should be at least a thousand stars.

 

The numbers would represent any positional errors in the stars, any wave like errors, or loss of dynamic range in the picture. How many pixels. In short, how close does the scope come to a space based 21 ton 'cost is no limit telescope'?

 

Then I would like to see, this test done for many different types and sizes of telescopes, so we could look at the cost factors involved. Where is the value? Which scope is most like Hubble, and still within our pocket books?

 

I think math can be used to achieve a bliss view, wild beyond our current languages can develop using intellectual concepts. I think we need more math, and that math is part of the astronomy as a field of science. Otherwise we just go around and around. How about measuring something, and doing the hard work of learning more?

 

Bill Savoie (stirring the pot).

Bill,

 

Stir the pot all you want.  There is indeed a lot of math that goes into telescope optics and their appraisal.

 

The point of my article has been -- Do the math if you want to, but most of all, build the telescope!  This is what my article concluded --    You don't have to do the math; the telescope I proposed was so simple that an enterprising ATM with a little experience could build one.

 

 

 

ed


 

#393 Daniel Mounsey

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Posted 31 December 2015 - 10:02 AM

I think we need more mathematics. We need to get past, our emotional attachments and how much money it cost us to see what we are seeing at night. I would think a telescope could be characterized by a single equation, which because of my name I would call the BS factor.

 

It would be nice if something like this could be done. Yet, ironically math is often the problem as to why so many people don't understand how optics actually work in reality. For example, people use MTF's, and yet, MTF's fail miserably to explain reality. Neat idea though.


 

#394 Asbytec

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Posted 31 December 2015 - 12:32 PM

For example, people use MTF's, and yet, MTF's fail miserably to explain reality. Neat idea though.

 

 

Daniel, I've always wondered why folks say that. MTF is just a theory, but it's derived from the wave nature of light to my understanding.

 

Now, I might agree it does not explain a few things. I've seen small craters on the moon at higher than maximum spacial frequency. How is that possible? I've even tried to observe doubles at the highest spacial frequencies where the obstruction has an advantageous diffraction effect, in theory. Yet, I cannot really get below Dawes (without some other explanation making it possible.) Well, MTF is not a measure of resolution or image detection. It's a measure of line pairs. So, it's really not designed to model such things.

 

Others tend to think MTF is not accurate because it always models some nice curve that never exists in the real world of seeing and tube currents. The trick seems to be, to model those as well in order to come up with a real time MTF performance graph. It will look nothing like the text book models. 

 

But why do folks put less stock in the MTF understanding these things? Well, except for being quick to point out the degradation of contrast at the first bright ring. Which, I agree with you, is not a distraction. It's probably real, but it's not been much of a problem for me.

 

I think the problem with MTF may be how we interpret the graph, we may expect it to show us things about our scope that it's not really designed to do. Especially in non lab-like bad seeing, lack of collimation, and with tube currents - where real time contrast transfer flat-lines and differs significantly from the textbook curve we see all the time. 

 

In any case, I am always curious as to specific reasons folks tend to distrust the MTF, specifically, and theory in general. 


 

#395 bsavoie

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Posted 01 January 2016 - 04:03 PM

Math is only good if it leads us to understanding, perhaps something we would miss if we just thought magically or politically. The beauty of Astronomy in my opinion is derived from the creation of the universe, and telescopes are a tool that allows us to look at creation.

 

My mother died two years ago, and I wonder, who was her mother, and when I allow myself to extrapolate, a telescope seems the best way to see my mother. I love using binoviewers, to try to get touch out of seeing. I want a full bandwidth with a large dynamic range.

 

So perhaps Astronomy is the one field of study which unites all things? Yes, we might argue about styles of telescopes and their technology, but the value is the unity that underlies reality.. Where did all these atoms come from? My real excitement comes from noticing awareness, just how that works. Awareness collapses the Schrodinger wave equation, so there is something about reality that is connected to consciousness. When we look 11 billion years back into time, with a 20 inch Dob, can we feel how we are involved? I love to examine that with open curiosity.

 

Bill 


 

#396 Relativist

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Posted 03 January 2016 - 03:03 PM

Math is one tool for man to communicate Physics, and Physics is determined by nature not man, even in this case. The future looks good for observing, and with a thriving maker movement DIY is going to get even easier.


 

#397 Asbytec

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Posted 04 January 2016 - 06:18 AM

Math is one tool for man to communicate Physics, and Physics is determined by nature not man, even in this case. The future looks good for observing, and with a thriving maker movement DIY is going to get even easier.

 

Sometimes I think it boils down how we interpret the physics...they say one thing, usually very specific, we think they mean something else. Myself included...


 

#398 bsavoie

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Posted 04 January 2016 - 12:18 PM

Yes, we need to build telescopes, because that ultimately tests all the math and all the equipment particulars. We all want better telescopes. John Dobsonian did that and it made all our lives better. What we would all love to do is to create a telescope that would be then taken up by a commercial company, that would drive the price down. Yes, that is exactly what John Dobsonian did.

 

So what is the next level up, and second how would you test that so we could all understand what the improvement was? I like the idea of using Hubble shots and making a comparison. Use some kind of Hamiltonian operator. Here is where I would need to study a bit more about math.

 

 Bill


 

#399 mark cowan

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Posted 04 January 2016 - 07:04 PM

Cor Berrevoets' Aberrator is what you want most likely. May not correspond to real world but it will show you comparative image degradation.


 

#400 kfrederick

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Posted 05 January 2016 - 12:08 PM

Yes, we need to build telescopes, because that ultimately tests all the math and all the equipment particulars. We all want better telescopes. John Dobsonian did that and it made all our lives better. What we would all love to do is to create a telescope that would be then taken up by a commercial company, that would drive the price down. Yes, that is exactly what John Dobsonian did.

 

So what is the next level up, and second how would you test that so we could all understand what the improvement was? I like the idea of using Hubble shots and making a comparison. Use some kind of Hamiltonian operator. Here is where I would need to study a bit more about math.

 

 Bill

Just think if the light from the obstructions was ware it should be Stars do not have spikes  The Chief can do unobstructed with big sizes  using a 20 inch unobstructed for close to 6 years  HST IMAGE

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Edited by kfrederick, 05 January 2016 - 12:11 PM.

 


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