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MKV
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Re: Hypo/Dialyte testing discovery new [Re: kfrederick]
      #5559113 - 12/07/12 11:27 AM

Quote:

Yours has a large obstruction and is a reflective system . All is not yet known . I know only good thing come from smart people trying new things .When they fail sometimes that is when most is learned .Nothing like having the real telescope to learn from . Obstruction effects are real but we are use to seeing it in the images . Having a design in OSLO is not like having the real telescope . Mark and John knows what he is doing we should relax we might all learn some.



You're right kfredrick, the CO is 1/3 the CA but that's because Mike I. Jones designed it for Dane as an astrograph with a huge field at that focal ratio. If you wanted smaller field you'd have much smaller central obstruction without serious diffraction effects.

I used Mike's configuration as an example of Mangin dialytes are capable of (mind you, at f/7.4 not f/15!), compared to dialyte refractors. The Mangin dialiyte is a true apochromat over a hughe spectral range, and a true flat-field anstigmat (no spherical aberration, coma or astigmatism to speak of) - and this is all possible with the cheapest glass (BK7, for all three elements. No exotic, expensive glasses needed!

As they say, it's hard to argue with success.

Obviously if I had to choose a dialyte I would go for a Mangin catadioptric system. If I wanted to experiement with different configurations, then all options are open. However, pursuing the ones already tried and retired seems to me somewhat pointless. That's all.

Reagrds,
Mladen


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Crayfordjon
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Re: Hypo/Dialyte testing discovery new [Re: Dave O]
      #5559117 - 12/07/12 11:30 AM

In spite of all that, the retro has no central obstruction or a tilted mirror, it has been perfected by Peter Wise and is an APO, it is cheaper than most with a very high performance, I stick to my guns on this and will always look for news ways to do things, no matter if certain dsigns are the "last word", they are not.

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MKV
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Re: Hypo/Dialyte testing discovery new [Re: Mike I. Jones]
      #5559132 - 12/07/12 11:38 AM

Quote:

Thanks for resurrecting that one, Mladen. I need to ping Dane and see if he ever built it. Shoulda been/will be a sweet scope.
Mike



Hi Mike, yes that was a definite keeper. Thanks. I am also curious if Dane gave it a try. If I remember the discussion of these, the clincher is the Mangin mirror which is in effect a Maksutov-like meniscus with all the thickness, and radius of curvature spot-on requirements that come with it. Also, the back surface of the Mangin has to be a super smooth, zone-free surface of reflector quality. Being convex, it would require advanced techniques and tooling to achieve.

So, I can understand why then a dialiyte refractor may be more attractive for novices, but there is no question which is a better optical system.

regards,
Mladen


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MKV
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Re: Hypo/Dialyte testing discovery new [Re: Dave O]
      #5559163 - 12/07/12 11:55 AM

Hello Dave O. The central osbtruction in this case is large (but not too large) because the system is an f/7.4 and designed to cover a large field. If you were to make it an f/10 then the CO will be smaller as well. As long as you can keep the CO about 20-25% of the CA the diffraciton effects are not too injurious.

I understand the fascination with unobstructed telescope, but, what's the point of having a slower, longer, more cumbersome system with no central obstruction and obvious uncorrected chromatic halo around bright images?

If I had to choose an unobstructed system and perfect color correction I would go with a Schiefspiegler, not a dialiyte refractor. Why bother with lenses?

However, let me be clear about something. It looks like some have misread intentions in what I wrote that are not there, so I want to stop it before it continues in that direction: There is nothing whatsoever that I wrote to DAVIDG that should be construed as criticism of experiments, or resistance to research in general. I simply stated that "if I had to choose a dialyte..." then I wouldn't waste my time with known/existing designs of inferior quality. Nothing else should be read into that statement. Thank you.

regards,
Mladen


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MKV
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Re: Hypo/Dialyte testing discovery new [Re: Crayfordjon]
      #5559167 - 12/07/12 11:57 AM

Quote:

In spite of all that, the retro has no central obstruction or a tilted mirror, it has been perfected by Peter Wise and is an APO, it is cheaper than most with a very high performance



Do you have his design to share?

Mladen


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Ed Jones
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Re: Hypo/Dialyte testing discovery new [Re: MKV]
      #5559828 - 12/07/12 07:03 PM Attachment (37 downloads)

Mladen,
The Jones-Medial is a refractor that has no obstruction, color, coma, field tilt and uses 3 pieces of common glass. I am at the assembly/testing stage on mine although I haven't had much time to work on it the last few months.


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kfrederick
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Re: Hypo/Dialyte testing discovery new [Re: Ed Jones]
      #5559850 - 12/07/12 07:30 PM Attachment (28 downloads)

Nice design ED If I was building it I would try my interlocking box with slots for the plates to hold the optics like I used on the CHief

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jgraham
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Re: Hypo/Dialyte testing discovery new [Re: kfrederick]
      #5559931 - 12/07/12 08:32 PM

Very, very cool Ed. I'm looking forward to your reports on this one.

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Dave O
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Re: Hypo/Dialyte testing discovery new [Re: Ed Jones]
      #5560099 - 12/07/12 10:44 PM

Wow Ed! You lost the obstruction and it didn't even cost more glass! Looks to be a dandy!

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MKV
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Re: Hypo/Dialyte testing discovery new [Re: Ed Jones]
      #5560197 - 12/08/12 12:02 AM Attachment (25 downloads)

Quote:

Mladen,
The Jones-Medial is a refractor that has no obstruction, color, coma, field tilt and uses 3 pieces of common glass. I am at the assembly/testing stage on mine although I haven't had much time to work on it the last few months.



That's the way to go Ed! Beautiful images. The Manign dilaytes are a proven design for fully corrected apochromatic configurations, in Newtonian, off-axis and Cassegrain modes. And no exotic glasses needed! Very impressive.

I would be curious if you could share with us the problems and challenges producing the Mangin mirror.

BTW, here is another Mike I. Jones original - a Cassegrain dialyte solution he and I talked about a while back: all spherical surfaces, fully apochroamtic and anastigmatic performance, simple N-BK7 glass.

Imagine, instead of a cumbersome Schmidt corrector plate, the front corrector is just a simple plano-convex lens! Think how much cheaper would it be to make catadioptric Cassegrainss this way. It brings such configurations into the ATM realm. This one doesn't even require a field lens! (the secondary is also a Mangin mirror)

This 8-inch f/20 design would make a fantastic, compact planetary scope to die for and perfectly executable by advanced amateurs!

Mladen

Edited by MKV (12/08/12 09:52 AM)


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Crayfordjon
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Re: Hypo/Dialyte testing discovery new [Re: MKV]
      #5560330 - 12/08/12 02:00 AM

Another Schupmann yet.

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Crayfordjon
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Re: Hypo/Dialyte testing discovery new [Re: Crayfordjon]
      #5560381 - 12/08/12 03:16 AM

Mark, does the Ed Jones Medial really belong on this thread? It is not a really a new idea in optical thinking, it is definately not an "outside the box" conception, which your design is! we have regressed into a mere recycling of the same old tired designs.

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nytecam
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Re: Hypo/Dialyte testing discovery new [Re: Crayfordjon]
      #5560394 - 12/08/12 03:59 AM

Quote:

Another Schupmann yet.


Hi John - Mark Harry's thread been highjacked - why do I get the strong impression some experts don't like your design - again
Of course anyone can reintroduce the original thread right here -right? [I love the 'right?' americanism]


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Mark Harry
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Re: Hypo/Dialyte testing discovery new [Re: nytecam]
      #5560471 - 12/08/12 07:32 AM

I'm just sitting back eating popcorn, or sipping a cup of Joe. (and tinkering away...)
M.


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Mike I. Jones
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Re: Hypo/Dialyte testing discovery *DELETED* new [Re: Mark Harry]
      #5560519 - 12/08/12 08:35 AM

Post deleted by Mike I. Jones

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Aljr
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Re: Hypo/Dialyte testing discovery new [Re: Mike I. Jones]
      #5560836 - 12/08/12 12:45 PM

That sounds great to me!!! , but John Wall (re)open the door. Ps.:I am the 50° fifth recreational design:

Quote:

And by "Joe" he means C2H5O

I am 100% behind exploratory, recreational optical design. It's how I stirred the pot and came up with the designs that Mladen brought up here. Ed Jones and Mark Harry are also recreational explorers, as is Peter Wise and 50-odd other names I could drop. I guess that's why I am offended by the term "tired old designs" above. I could say that this "hypo" thing is also just a recycling of "tired old designs", in this case a Petzval lens, albeit with uncorrected Petval field curvature and lateral color. That's the only "AHA I get it!!" moment I get from a "Hypo". But knowing that doesn't trivialize it or render it undesirable to try building - it's a simple way to achieve a large-aperture refractor while only needing to make but one full-aperture refractive element. That's all Mark has presented this to you as, and I'm looking forward to his First Light report. But can we also respect and welcome other designs as well, and not practice what is effectively optical design racism?
Mike




Edited by Aljr (12/08/12 12:49 PM)


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Crayfordjon
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Re: Hypo/Dialyte testing discovery new [Re: Aljr]
      #5560940 - 12/08/12 02:03 PM

I am afraid that the term "tired old design" has been appended to the Hypochromat, well of course this shews very clearly that once more my thesis has been briefly scanned and all the wrong conclusions perceived, good old knee jerk reaction as usual. Now if you read my thesis carefully and take in all the points laid down you will get a different perspective of what I am trying to say, and with a bit of luck it will be the right one just for once. The term tired old sesign in the case of the Hypo shews I am right here in saying this. So let me remind you once more, the Hypo was discovered by me four years ago when I noticed an anomaly in the image quality which just should not have been there while I was analyzing a retro lens set on the optical bench in my lab. I realised that this would produce a very simple, if imperfect refractor. I noticed subsequently that this anomaly does not appear in any of the optical text books, so I assumed that it was a new discovery. I have repeatedly explained the simple principles of the Hypo on this forum with basic geometrical optical diagrams, and yet the message did not and still has not gone across. There are a small few who took the trouble to understand what I was saying and they understood, but just a very few. Mark is one those few. and Aldevio in Brazil took the design on board with great enthusiasm, and he has now built and researched several versions of his own. I just mention these two. It seems to me that on the ATM forum most have entrenched ideas based on those designs that have been with us since the German physicists made all those discoveries back in the 19th century, and of course you cannot discover any more, because it has all been done and dusted, a prejudice cast in tungsten carbide. The old reaction to Marks research is that it has all been done before by Petzval, the fact that Mark has come up with an achromatic version of a Hypo does not seem to get across. Even the Hypo has been described as a Petzval deriviative, which it definately is not as it bears only a vague morphological resemblence and no more. When I joined CNR ATM forum I was nticipating lively and imformed discusions abouit new ideas, but so far in all thast time, only a very small handful have done this, 99% of the time it has been carping destructive critisism all the way.

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DAVIDG
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Re: Hypo/Dialyte testing discovery new [Re: Aljr]
      #5560954 - 12/08/12 02:13 PM

I think the push back might be that the spot diagrams are not very good. Experimentation is great when you don't know the out come or your testing a theory. It is what I do for a living. In this case the spot diagram is clearly predicting the out come and the theory behind the raytracing math is solid. One stirs the pot around here when a design is posted that shows excellent results via raytracing. In this thread alone there have been a number of new designs discussed. Why have they been built or being built? Because the spot diagram showed the excellent results that could be achieved.
- Dave

PS Mark might want add a splash of hydrogen to that C2H5O 'Joe' to flavor it up so it more like CH3-CH2-OH. That additional 'H' makes a big difference in the taste, trust me !


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Aljr
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Re: Hypo/Dialyte testing discovery new [Re: DAVIDG]
      #5560995 - 12/08/12 02:42 PM

All humans now know that the earth is round / spherical, but many humans can not do an experiment to prove. And many researchers believe in the "perfect theory". the "perfect theory" explains everything. I disagree.
If there were a "perfect theory", missions to Mars should be canceled. If there were "perfect theory", would not have discovered a huge oil reserve here on the coast of Brazil.


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DAVIDG
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Re: Hypo/Dialyte testing discovery new [Re: Aljr]
      #5561093 - 12/08/12 03:44 PM

What new theory are you trying to prove with a Hypo Dialyte ? The math discriping the interaction of light with refractive and reflective surfaces has been well established and tested many times. So unless there is a bug in the software of both OSLO, Zemax or any other raytracing program, they predict the results extremely well of any optical design that uses these materials. There are millions of designs to prove this. So why should one throw all that data away and experiment with a design that using these proven tools that shows it not to have very good performance ?

- Dave


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