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Mike I. Jones
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10" f/3.5 Astrograph with Rosin focal reducer
      #5521709 - 11/15/12 06:40 PM Attachment (148 downloads)

Been a while since anyone tossed a new design to the sharks here. So, give 'er the works!
Mike


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5521713 - 11/15/12 06:43 PM Attachment (90 downloads)

Here are the spots. Not too bad, pretty much DL at f/3.5 over the 1.3" field diameter, 2.1 deg. angular FOV. It's color corrected over the 0.41-0.75µm band, could probably go a little wider with broadband AR coatings. Uses standard 4" diagonal mirror with 0.19" offset away from focuser and toward the primary. Primary is hyperbolic, CC=-1.8026. Just means figure it 1.8026X stronger than the equivalent paraboloid.

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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5521714 - 11/15/12 06:44 PM Attachment (131 downloads)

and here's the OSLO-EDU file. Enjoy!
Mike


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Mark Harry
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5522436 - 11/16/12 08:35 AM

Got it saved, thanks Mike.
***
My OSLO version says the reducer glass isn't in the catalog, and it barfs. How recent is your OSLO version?
M.


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mark Harry]
      #5522636 - 11/16/12 10:46 AM

Version 6.6. Time to update yours?
Mike


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Mark Harry
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5523333 - 11/16/12 07:12 PM

6.3.3 .

Hate to mess with it, knowing my luck.
M.


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mark Harry]
      #5523530 - 11/16/12 10:01 PM

Nah, not a biggie, try it. Download the 6.6 version, install it in a new and separate folder, and you're in business. I keep my *.len files in a folder separate from any version installations so they don't get whacked.
Mike


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5524070 - 11/17/12 10:18 AM

This is a fast Over corrected newt with a 3 lens corrector ? Is the over correction for coma ? Oslo is great Be nice if you and others would have a link to all the oslo files posted . There must be over 100 designs . Thanks for posting

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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5524736 - 11/17/12 05:28 PM

In Rosins, you allow the primary conic constant to float to offload correction of spherical aberration from the corrector group to the primary. That leaves the corrector with more flexibility to correct chromatic and field aberrations.
Mike


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5527926 - 11/19/12 01:13 PM

Where can a lens be gotten ? Field aberrations? Is that coma .

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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5528056 - 11/19/12 02:09 PM Attachment (42 downloads)

Quote:

Where can a lens be gotten ? Field aberrations? Is that coma .



K, there is some miniscule residual coma, but the images are still diffraction-limited for all practical purposes. Mike's Rosin corrected scope is a superb solution, both visually and photographically. It would be interesting to comapre it to Paracorr's performance.

The PSF images below show just what the stars images would look like under very high magnification. The image patch for each image is 25 microns wides, so you can see the images themselves are no bigger than 5-6 microns.

The corrector lenses can be ordered from professional companies, but they won't be cheap. Almost not worth it. They could be made using a small spindle but not by hand.

Mike: It would be interesting to see a tolerance analysis of the configuration. It's definitely a very advanced project - and very promising.

Mladen

Edited by MKV (11/19/12 02:11 PM)


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5528247 - 11/19/12 03:47 PM

Thanks, Mladen. Was beginning to wonder if you saw it. Agree, that triplet set of lenses, fully BBAR coated, would probably run $3-4K from a place like Cumberland. This design would be at the far end of any telescope bucket list of mine, if ever. But it's still fun to experiment with designs like this on cloudy nights.
Mike


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5529360 - 11/20/12 04:15 AM

Hi Mike, yes I did see it, and it's rather amazing what an extra element can do.

Depending on tolerance requirements (OSLO.edu has only limited capacity for this type of work), the corrector will probably be the priciest element of the configuration.

On the practical side, if tolerances are within amateur production capabilities (and I mean advanced amateurs!), then this project would be a lot more financially attractive - especially for big, fast mirrors!

The highly aspheric, fast, primary is another story. Making an accurate f/4 highly hyperboloidal primary requires a well tooled and experienced worker, unless custom-ordered mirrors are not a financial burden.

Speaking of tinkering on those cloudy nights, it would be interesting to do a direct theoretical comparison of this Mike I. Jones-Rosin corrected system as opposed to a 10-inch f/3.5 Newtonian with a Paracorr and a 10-inch f/3.5 Newotnian using a Wynne-type corrector (both of which are commercially available).

At any rate, seeking such solutions on cloudy nights has produced many an attractive design, and this is definitely one of them. Excellent work, Mike.

Mladen


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5529463 - 11/20/12 06:49 AM

Hey what about a Herring? or Hamiltonian yolo Be nice if one thread had all the designs ever posted in Oslo

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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5529497 - 11/20/12 07:16 AM

Thanks again, Mladen. I wish we all had the designs for Paracorr, ASA, etc. correctors so we could do the comparisons you say. Those are closely guarded family jewels, I'm sure. Many of us can and have designed several different Paracorr-type coma correctors that give very nice performance. But the likelihood of exactly modeling a commercial product, even if you disassembled one and took a micrometer and spherometer to it, is nearly zero. You'd have to de-bond cemented elements and measure the interior radii, and take each element and do a focus-vs-wavelength scan to try to reverse engineer the glass index and dispersion. Who's gonna want the design so bad you'd irreversibly destroy a $470 product? Not me!

I can take a look at the tolerances on this triplet Rosin. Typically, tolerances tighten up with increasing element power, surface curvature and/or marginal ray incidence angles.

Mike


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5529510 - 11/20/12 07:25 AM

That sounds like a great thing you could do for everyone here, Kevin. Can you go back through all the ATM forum posts, and even back into the archives, and download all the OSLO files into a common folder? Organize the files into classes of telescopes, then ID gaps in the collection (like the Herrig, for example). We could talk to the CN admins about setting us up a community OSLO file for all to access and add to.

Mike


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5529667 - 11/20/12 09:35 AM

I have some saved already was not sure if the authors would be ok with me posting them .I like your idea I know You Dave And ED have alot .

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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5529802 - 11/20/12 10:48 AM

Quote:

I have some saved already was not sure if the authors would be ok with me posting them .I like your idea I know You Dave And ED have alot .



I don't think posting a list of links to the published designs would violate the TOS.

Mladen


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5529827 - 11/20/12 10:58 AM

Hasn't everything posted on Cloudynights already been blessed by each of the authors for public domain? I don't see a TOS issue at all in going back and re-downloading OSLO designs in the forums and archives and collecting them together into a public file. Those OSLO files wouldn't have ever been posted if the authors weren't fine with doing so, right?
Mike


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5529837 - 11/20/12 11:04 AM

I think if the authors post what they have to share on one link would be cool .Also some info on using Oslo and what some of those big words are .Be great if more got made . Thanks for all the cool designs I am here to help .

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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5529904 - 11/20/12 11:30 AM

Hi Mike. You're absolutely right about the trouble, cost, effort (never mind the ethics involved), etc. of retro-engineering registered products. What I had in mind was, of course, comparing your Rosin-type triple corrector to Paracorr and Wynne type condifugrations that have been suggested as possible close replicas of the same. In my relatively short time on CN, I remember both corrector types being mentioned and discussed, possibly some in archived files.

Mladen


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5529920 - 11/20/12 11:37 AM

Mike I was told by a mod (not you) that one may not post someone else's picture (as an example), even in context - and even if crediting the author.

Mladen


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5529938 - 11/20/12 11:44 AM

Mike, speaking of reto-engineering, some people obviously feel it's worth the effort.


http://img405.imageshack.us/img405/5439/es14ethos2.jpg


as seems to be the case with Ethos. Given this precedence, I am really surprised no one has come up with a Paracorr copy. Either it's not lucrative enough, or perhaps the laws have changed since this photo was taken.

Mladen


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Pinbout
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5530542 - 11/20/12 04:15 PM

Quote:

some people obviously feel it's worth the effort.


http://img405.imageshack.us/img405/5439/es14ethos2.jpg







I've always heard about that image but never saw it. Thanks


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Gert
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5531422 - 11/21/12 01:00 AM

Hi Folks,

Is this configuration used by the ASA astrographs?

http://www.astrosysteme.at/eng/astrographs.html

...
H-SERIES
The astrograph of the H-Series have a hyperbolic primary mirror...

Clear Skies,
Gert


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Gert]
      #5531718 - 11/21/12 08:52 AM

Who knows? Only the ASA folks, and they ain't tellin'!

It could very well be similar to the ASA designs. I could probably get a good DL-ish design at f/2.8 over the same field and spectral band, but it would be a real bear to build and keep in alignment. f/3.5 is plenty fast for me.

Mike


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Loren Chang
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5533784 - 11/22/12 11:27 AM Attachment (68 downloads)

Hello Mike,

A beautiful design, again. I found similiar ideas in my database. Post one of them only here. Dose this Ross corrector variant works on newtonian?


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5534176 - 11/22/12 04:22 PM

Quote:

Dose this Ross corrector variant works on newtonian?



Loren, I hope you won't mind if I jump in on this. In order to get this level of correction, the primary mirorr must be hyperboloidal. A Ross corrector reduces coma in a Newtonian (i.e. paraboloidal primary), but at the cost of introducing spherical undercorrection - which is offset by hyperboloizing (overcorrecting) the primary. But then it's no longer a Newotnian.

Maybe modern glass melts offer a possibility of creating a Ross/Rosin type corrector that would correct for coma in a Newtonian without significant spherical residual. It may be worth looking into this. Mike, what say you?

Mladen


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5534576 - 11/22/12 10:45 PM

I say, don't talk with your mouth full! Been enjoying family and food all day. I'll get back into CN maybe this weekend.
Gobble 'til ya wobble,
Mike


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Loren Chang
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5534955 - 11/23/12 07:30 AM

In order to get this level of correction, the primary mirorr must be hyperboloidal. A Ross corrector reduces coma in a Newtonian (i.e. paraboloidal primary), but at the cost of introducing spherical undercorrection - which is offset by hyperboloizing (overcorrecting) the primary. But then it's no longer a Newotnian.





Hello Mladen,

Everyone is welcome. I understand what you said. For Newtonian, Wynne corrector gives excellent image but is diffcult to make. Ross corrector is simpler though causes spherical aberration. What I'm asking is will it be better to add one more element in Ross for newtonian?



Hello Mike,

Waiting for your comment! I'm playing a F/10 superachromat design in USP 2009/0296201. Take a look if you are interstring. I'll post it in another thread.


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5536700 - 11/24/12 07:07 AM

Hi Loren. My point was that if you add a third element to a paraboloidal mirror you end up with a Wynne-type corrector.
_____

Hey Mike, I hope you had a nice Thanksgiving. It appears that your corrector's first surface (#4) is the "hairline trigger" that must be spot on to a very high precision - I mean a radius of curvature accurate to a few ten thousands of an inch. Vow!

Radii of the real element (#8 and 9) have more generous tolerances and could be used to counterbalance #4 with much greater radius tolerance.

But that means the radius of #4 must be known to better than 0.05%. Seems like this would be the first surface to be finished and then all other sufraces would be built around that one - again to very high precision.

I also find that perhaps thickness/spacings of the correctors elements must be in the range of ±0.0001 inch, and that the diffraction limited focal range is is in the order of only ±0.0005 inches.

As I said , this is just a preliminary look, using a slider wheel tool. Curious to see what your tolerance data will tell us.

Mladen


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5536924 - 11/24/12 09:51 AM

Just checking in briefly. Mladen, when you varied your slider wheels, what compensators did you use? You need to have compensators that can be easily changed during tolerancing, such as refocus, airspaces, etc. Otherwise you get just what you found, outrageously tight tolerances, when they needn't be. In this application, the BFL could vary a millimeter or so and have no impact on system utility. The BFL, airspaces and distance from the diagonal can all vary a small amount by re-optimizing. I will use all those values when I get back and study the tolerancing.
Mike


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5536964 - 11/24/12 10:15 AM

Mike, you're so right. I overlooked the refocusing. My bad. Indeed, once you compensate, the tolerance range becomes more realistic.

Mladen


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ed_turco
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5537102 - 11/24/12 11:40 AM

May I say something a little off topic? Robert Lurie in his 1976 paper proposed a system with a full lens corrector (Asymmetrical in form and two BK7 elements in contact) with a hyperbolic mirror; it was a dandy. I know that the term "Too much glass" is bandied about but the system was not only coma corrected, but anastigmatic, meaning no astig either. I wish I had built it. Mike, any comments? I think I might have the numbers somewhere...

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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: ed_turco]
      #5537527 - 11/24/12 04:56 PM

Hi Ed,
We're still out on the road for holidays. If you'll post up Lurie's prescription, we can give it a look in ZEMAX and OSLO.
Mike


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kfrederick
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5537608 - 11/24/12 05:54 PM

Mike how big can this design go ? Thanks

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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: ed_turco]
      #5537852 - 11/24/12 09:09 PM

Ed, Mike: Lurie's 1975 work gave G-sum equations for a corrector to be used in conjunction with a parabolic (not hyperbolic) mirror. It was intended to serve as a means of converting ordinary Newtonians into anastigmatic cameras. But his principle can be applied to an entire family of conic mirrors, not just paraboloids.

I discussed his design and one special case he intended for amateurs (using an ellipisoidal mirror and a plano-convex, plano-concave corrector) in The Best of Amateur Telescope Making Journal, Volume 2, 17-18.6 "Lurie Anastigmats", pp. 375-392, Willmann-Bell, 2003.

I have his 1975 JOSA article and will gladly post the equations - unless Mike thinks it's off topic.

Mladen

Edited by MKV (11/25/12 12:59 PM)


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wh48gs
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5538700 - 11/25/12 12:53 PM Attachment (31 downloads)

Loren,

That's interesting arrangement, positive element in front. still only four glass-to-air surfaces. When scaled up to 250mm f/3.5 it is not quite as good as Mike's color-wise, but that wouldn't cause any difference in practical terms. But why use FPL51, if FPL53 is (I think) cheaper? Here's what it looks like.

Vla

Edited by wh48gs (11/25/12 01:28 PM)


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cjc
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5539779 - 11/26/12 03:25 AM

Quote:


...
Speaking of tinkering on those cloudy nights, it would be interesting to do a direct theoretical comparison of this Mike I. Jones-Rosin corrected system as opposed to a 10-inch f/3.5 Newtonian with a Paracorr and a 10-inch f/3.5 Newotnian using a Wynne-type corrector (both of which are commercially available).
...
Mladen




These are not quite what you want, but there is a coma corrector design with two cemented doublets in the Telescopes, Eyepieces, and Astrographs by Smith, Ceragioli and Berry. Orion Optics have spots for a set of F3.8 Newtonians with an Optimised Wynne corrector with the 10" spots here:

http://www.orionoptics.co.uk/AG/ag10spots.html

and the others being accessible from here (follow the red links in the table):

http://www.orionoptics.co.uk/AG/agrangeand%28ota%29t.html


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: cjc]
      #5539823 - 11/26/12 05:34 AM

Thanks cjc. Interesting "hybrid" corrector. Bear in mind that the Rosin works only with a hyperbolic mirror, which means the corrector must be used all the time, whether observing visually or photographically. The others, the Ross, Wynne, Paracorr, and the Orion's version work on your ordinary Newtonians with parabolic mirrors which can be used with or without the corrector. Of course, if you have an f/3.5 Newotnian you'd be using the corrector all the time!

The design and the results of all of these are either public knowledge or can be obtained by raytracing, but not of Paracorr. My understanding is that it consists of two cemented achroamts. It would be interesting to see how Paracorr would compare in an f/3.5 Newtonian, one degree off-axis, against the other correctors.

Mladen


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Loren Chang
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5540287 - 11/26/12 01:12 PM

Quote:

Hi Loren. My point was that if you add a third element to a paraboloidal mirror you end up with a Wynne-type corrector.




Hello Mladen,

You mean finally I'll get a Wynne corrector?


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5540606 - 11/26/12 04:22 PM

Hi Loren. What I meant to say is that, for a parabololoidal mirror, a high quality corrector at such fast focal ratios will most likely resemble the Wynne configration.

Paracorr's design is not public knowledge, but it is my understanding that it does not resemble the Wynne configuration. Rather I read somewhere that it consists of two sets of cemented achromats. Regardless, since it's a family secret of sorts, it is impossible to say how good it is on f/3 to f/3.5 paraboloids.

So far, all high performance correctors for very fast Newtonians resemble the Wynne corrector, having either three or four elements.

Mladen


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MKV
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5541045 - 11/26/12 09:04 PM

Loren, I just found this site, which discusses the performance of three commercial Newotnian coma correctors, a Wynne, Paracorr, and RCC (Celestron's) brand.

The article is in French (thank you, Lord, for Google Tranalate!). The author presents imaging evidence of the performance and concludes that the Wynne and Paracorr are abot the same for f/3 to f/3.5, but that the Wynne has less vignetting and covers larger image frames. At the same time, he concludes that Paracorr is the most cost-effective product.

The plot thickens.

PS I would also like to add that if the Paracorr is indeed a set of two achromatic doublets then it beats any other corrector thus far in manufacturing as well. The Wynne requires very thin, deeply curved lenses that look more like potato chips! Not an easy thing for an amateur.

The Rosin requires a pretty strong hyperbolic primary and a couple of meniscus lenses, with slightly more agreeable thickness, but still n ot easy. One must never forget that an f/3 or f/3.5 hyperboloid is not an easy thing to make especially because many of the available tests presnet a problem with full illumination of optics - and the steeper the curves the tighter the tolerances!

So, at least one, rather well documented test seems to favor Paracorr as the corrector of choice for Newtonians.

Hopefully we didn't drift too much off topic.

Mladen

Edited by MKV (11/27/12 07:09 AM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5541107 - 11/26/12 09:38 PM Attachment (46 downloads)

Most ATMs aren't into lens making. 8ere's an 8 inch F/4 hyperbolic using off-the-shelf lenses.

Edited by Ed Jones (11/26/12 09:45 PM)


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Loren Chang
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: wh48gs]
      #5541403 - 11/27/12 12:35 AM Attachment (47 downloads)

Quote:

But why use FPL51, if FPL53 is (I think) cheaper? Here's what it looks like.




Hello Vlad,

Why FPL51? The relative price of fpl51 to BSL7 is cheaper.

OHARA Glass

I do have several FPL53 designs. And you can even use ordinary glass. Here is OSLO file.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5541478 - 11/27/12 03:10 AM

As to Paracorr design, this is from the Optcorp page:

Paracorr (parabola corrector) uses 2 multi-coated, high index doublets, is completely color-free, center and edge, and installs like a Barlow. Coma is corrected so well, the diffraction limited field area of an f/4.5 Dob/Newt is increased 36 times!" -- Al Nagler

For spot sizes see:

http://www.televue.com/images/TV3_Images/Images_in_articles/Paracorr_2_chart.jpg


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: cjc]
      #5541591 - 11/27/12 07:23 AM

Thanks Chris. I guess that settles it. The phogoraphic evience I referenced to Loren seems to agree with Nagler's data. At under $500, as a simple add-on, it is both cheaper and more efficient than other correctors - and you can keep your existing parabolic mirror! There is no way a Rosin-type astrograph, or a Wynne-type corrector, can be manufactured at a comparable price.

As for Paracorr's vignetting, most folks with imaging devices today have digital processors of such size that worrying about vignetting hardly seems relevant.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Loren Chang]
      #5541634 - 11/27/12 08:04 AM

Loren,

Quote:

The relative price of fpl51 to BSL7 is cheaper.




You are right. Not long ago I saw the pressing price table, and only remembered FPL53 looking relatively cheap (obviously, processing adds quite a bit).

Yes, common glasses can be used (in the arrangement with the cemented positive doublet in front as well), but they always have the problem of not been able to correct for longitudinal and lateral color at the same time. When scaled to 10-inch f/3.5, and with minimized longitudinal aberration, the 406-8300nm spot at 1 degree off axis is spread over more than three green Airy disc diameters, laterally (not much less at 0.7 degrees). It is still within 0.025mm circle, but would probably result in elongated star shapes. The far red end is not that important, since CCD sensitivity drops toward it, but it is still there.

Vla


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5541649 - 11/27/12 08:17 AM

Ed, how can you have BK7 next to BK7, and shouldn't all the thicknesses be negative? Could you present this design in a standard tabular form, i.e. roc, space, medium, conic? Thanks.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5541724 - 11/27/12 09:31 AM Attachment (76 downloads)

Here's a 2-doublet coma corrector solution I messed around with over the weekend that probably works about as well as the Televue Paracorr, at least for f/4.5 mirrors and slower. I didn't try it with faster mirror focal ratios, but this at least shows it can be done with two doublets, for a usable field of view and over a wide spectral band.

Might be a good project to work further on with lower focal ratios. We could call it the Cloudynights Collective Coma Corrector!

Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5541726 - 11/27/12 09:32 AM Attachment (40 downloads)

and here's the without/with performance using this coma corrector.

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5541793 - 11/27/12 10:21 AM

It would be nice if Roger Ceragioli were to publish the specifications for the GSO corrector.

I note that the two lens Baader MPCC is due to be replaced possibly due to its spherical aberration of which its competitors are free. I wonder if the new one will have two doublets, like the Paracorr, GSO and the modified Ross-type design in Telescopes, Eyepieces, and Astrographs by Smith, Ceragioli and Berry. In passing that book says that it is not easy to produce an add on Newtonian corrector to fit in a 2" barrel that completely corrects coma. Their design does not fully correct coma but they say it is similar in performance to coma correcting modules available on the amateur telescope market. I am not sure if this includes the recent Paracorr II. Perfect coma correction is apparently possible with non-modular solutions such as the three-element Wynne corrector published in the same book.

I also note the availability of a coma correcting barlow from APM with published PSF, but no design. See: APM Coma Barlow.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5541817 - 11/27/12 10:32 AM

I think you did a great job with this corrector, Mike. Mr. Nagler claims that Paracorr II does not exceed the Airy disk at f/4.5, and only at f/3.5 at distance greater than 15 mm off axis.

Without any public data there is no way to confirm this theoretically, and precision images taken with Paracorr II are not suitable for metrics.

PS Judging from the pitures of the Paracorr add-on, I'd say Nagler's specing between the doublets is a lot closer than yours. Maybe therein lies the answer.

Mladen

Edited by MKV (11/27/12 10:35 AM)


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Loren Chang
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5541858 - 11/27/12 10:56 AM

Quote:

We could call it the Cloudynights Collective Coma Corrector!




Hello Mike,

AKA C4?!


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5542664 - 11/27/12 07:17 PM Attachment (35 downloads)

Mladen,
Here is what this looks like. I do agree with you however that the Paracorr makes more sense. By the time you buy 4 coated lenses you could almost buy a Paracorr.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5543317 - 11/28/12 06:31 AM

Quote:

Mladen,
... I do agree with you however that the Paracorr makes more sense...




Or even an Astro Optik corrector, spots here: Newtonian 3" Wynne Corrector.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5543361 - 11/28/12 07:40 AM

Quote:

Mladen,
Here is what this looks like. I do agree with you however that the Paracorr makes more sense. By the time you buy 4 coated lenses you could almost buy a Paracorr.



Thanks, Ed. Much obliged for the picture. I am not used to Zemax design presentation. I only now noticed that you have a diagonal mirror in that configuration, which would explain the change in sign.

Don't forget that, in addition to the cost of the lenses, there is also the cost of a precision machined lens cell and anodizing. I wonder if the Paracorr people took all that into account when they decided on the price of their product, i.e. to make it just not worth one's while to pursue a DIY approach. If they did, it's a smart marketing strategy!

Clearly, the cost, compactness and performance of the Paracorr is hard to beat, so if I were seeking corrector solutions I would be looking into two cemented doublet designs.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5543366 - 11/28/12 07:45 AM

Mike,

Golly!

Ed


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: cjc]
      #5543503 - 11/28/12 09:52 AM

Quote:

Or even an Astro Optik corrector, spots here: Newtonian 3" Wynne Corrector.



Chris, what's the price of AO's corrector? Paracorr 2 goes for about $450. The field coverage for both is the same (50 mm). The Wynne has a slight (but not significant or crucial) advantage in the zise of the fully illuminated field.

For vignetting to become a factor you'd need 60x60 mm CCD processors, something most amateurs can only dream of (a large format reconditioned Hasselblad camera goes for $20K!).

Regular SLR processors are 14x24 mm, well within Paracorr's fully illuminated field.

Also, the Wynne is a 3-inch corrector that doesn't fit into standard 2-inch focusers.

And the spots assume the limit of 20 microns, but today this old-fashioned (film grain) size limit has been surpassed as digital images are capable of resolution of detail smaller than 20 microns.

Mladen

Edited by MKV (11/28/12 09:54 AM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5543788 - 11/28/12 12:34 PM

Fromm APM the ASA 3" Wynne Corrector is 1,020 EUR including 19 % Tax, which would not be payable to the US, so somewhat more expensive than the Paracorr. However, it has the advantage of being a 0.95x reducer rather than the 1.15x Barlow of the Paracorr. There is a comprehensive range of ASA coma correctors including 2" models (the cheapest of which is 468 EUR), with various amounts of extension/reduction and a model for Schmidt-Cassegrains, see Reducers-Converter-Correctors. I wonder if it is an ASA corrector in the Orion UK AG astrograph Newtonians which I referenced earlier.

I do note that the spots are reference to 20 microns rather than perhaps 10 or even 5 which is common today and your comments about affordable cameras. However 3" focusers are becoming more common because 2" will inevitably vignette 50mm sensors and the widest eyepieces. I understand that ES has a 30mm, 100 degree, 3" eyepiece in testing...


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5543923 - 11/28/12 01:44 PM

Notice that Ed synthesized a lens by using a plano-CX and plano-CC of different radii, plano sides together, and made from the same glass (BK7). He's clever that way!
Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5544047 - 11/28/12 03:09 PM

Quote:

Notice that Ed synthesized a lens by using a plano-CX and plano-CC of different radii, plano sides together, and made from the same glass (BK7). He's clever that way!
Mike



Yes, that is very clever. With off-the-self lenses he had no choice but to combine them.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: cjc]
      #5545177 - 11/29/12 09:42 AM Attachment (31 downloads)

Chris, anyone who needs a 3-inch focuser can just as well custom order the optics because chances are such a person will most likely have a camera with the processor to match, and the sky is the limit (no pun intended).

For an average Joe ATM, even if skills and tooling are no obstacle, it simply doesn't pay to try to make correctors lenses and hyperboloidal mirrors if one can buy a corrector for an existing paraboloid for a price between $450 and $600.

The only possible exception to this fact is Ed Jones' Rosin with commercially available lenses. But you get what you pay for.

That being usually true, let me say that Ed's configuration is darn good given that the corrector is made up of off-the-shelf lenses, but don't expect to get the performance of Mike Jones' optimized Rosin design.

Even if you can get such lenses at bargain prices, and even if they meet the tolerance requirements (which we still don't have), you still have to make, or have someone make for you, a precision corrector cell, anodize it, etc.

If scaled to a 10-inch f/4, Ed' design has a diffraction-limited field four times smaller than Mike's 10-inch f/3.5 configuration, mainly due to astrigmatism.

If you're willing to settle for the outdated 20-micron photograpahic resolution, then Ed's configuration can cover a field of up to 24 mm across photographically, but at a considerable loss in limiting stellar magnitude.

However, plopping a Paracorr into your focuser of your already existing Newotnian is simply unmatched in convenience, and in terms of saving time and money - and a large corrected fov.

Ed Jones, do you have any idea how much your off-the-shelf lenses would cost? Thanks.

Mladen

Edited by MKV (11/29/12 09:56 AM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5545448 - 11/29/12 12:21 PM

Quote:

However, plopping a Paracorr into your focuser of your already existing Newotnian is simply unmatched in convenience, and in terms of saving time and money - and a large corrected fov.




I agree entirely and parabolic mirrors are more easily made or bought from a wide range of sources. I apologise if I have highjacked the thread which is after all in the ATM forum. I was really only wanting draw attention to off the shelf options, and not only the Paracorr. At a higher cost there are the ASA devices, while for less there is for example the Astro-Tech/ GSO corrector designed by Roger Ceragioli which is currently on offer at $120 and apparently in stock at Agena!


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: cjc]
      #5545518 - 11/29/12 01:06 PM

Chris, you may answer via PM if you feel this is too much off topic, but I think some people may be interested. The Astro-Tech (GSO) comma corrector is indeed cheap but not without problems (and there's plenty on the web about that). Also, pictures are worth a thousand words, and I don't see any spot, MTF, PSF, interferometric, or imaging evidence of the product's performance.

I am not promoting Paracorr 2. I am simply establshing that, so far, the makret has one fairly sucessful and affordable product by that name and that making one's own corrector and precision lens cell (not to mention hyperbolic primary) is not practical or possible for most amateurs.

To the Admin: please consider creating a theoretical design forum where one can post theoretical designs and discuss optical theory at liberty.

Mladen

Edited by MKV (11/29/12 01:11 PM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5545733 - 11/29/12 03:45 PM

Only 63.4% of the light reaches the focus .About the same as a 6 inch unobstructed . Unless I am reading Oslo wrong

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5545780 - 11/29/12 04:08 PM

Guys - Don't sweat it, I'm not worried about this particular thread going off topic. I kind of started it to re-seed these kinds of discussions anyway.

Hijack away!
Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5545811 - 11/29/12 04:32 PM

Quote:

Guys - Don't sweat it, I'm not worried about this particular thread going off topic. I kind of started it to re-seed these kinds of discussions anyway.

Hijack away!
Mike



Thanks, Mike!


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5545814 - 11/29/12 04:34 PM

Quote:

Only 63.4% of the light reaches the focus .About the same as a 6 inch unobstructed . Unless I am reading Oslo wrong



Which one are you talking about, K?


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5545824 - 11/29/12 04:40 PM

The Oslo file says 63.4% of the rays reach the focus in Mikes 10 inch rosin . So it it is like a 6.34inch unobstructed in light .

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5545935 - 11/29/12 06:09 PM

More like a 7.94"???
M.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5546253 - 11/29/12 09:08 PM

Mladen,
I think lenses this size will cost about $100 or more each so as I said you can buy a Paracorr for almost the same money. This was just my best try at using off-the-shelf lenses to make a photographic scope.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5546353 - 11/29/12 10:10 PM

Quote:

Mladen,
I think lenses this size will cost about $100 or more each so as I said you can buy a Paracorr for almost the same money. This was just my best try at using off-the-shelf lenses to make a photographic scope.



Thanks Ed. I think you did a fantastic job!

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5546421 - 11/29/12 11:04 PM

Quote:

The Oslo file says 63.4% of the rays reach the focus in Mikes 10 inch rosin . So it it is like a 6.34inch unobstructed in light .



K, the "unobstructed" aperture residual is simply the difference in areas between the full aperture and the central obstruction.

The full aperture radius is 5 inches, so the full aperture area A1 = Pi*r^2 or Pi*25 = 78.5398 sq. inches. The radius of the central obstruction is 1.894 inches, and the CO area A2 = Pi*1.894^2 = 3.14159 sq. inches. Subtracting A2 from A1 gives A3 or the area of the unobstructed residual, which is A3 = 67.27 sq. inches. This area is then A3 = Pi*r3^2, and its radius r3 = (A3/Pi)^0.5.

And since the diameter is 2*radius, the equivalent unobstructed aperture diameter D3 = 2*(A3/Pi)^0.5 = 9.25 inches, which gives a residual focal ratio of f/3.8, instead of the geometric f/3.5.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5546511 - 11/30/12 12:27 AM

Don't get T-number (light gathering power) and F-number (resolution) mixed up. The system aperture is still 10" and focal length is 35.468", so the focal ratio (F-number) is still f/3.5468 (f/3.5 close enough). The visual resolution follows the focal ratio per the obscured system diffraction disk formula. The T-number relates to the system's actual light gathering power, meaning the optical flux impinging on a camera focal plane (thus driving exposure times) and the eye (thus driving limiting magnitude). In this system focal plane or retinal irradiance (in watts/cm2) appears to come from an f/3.8 system, not an f/3.5 system. If transmission losses in the system are also accounted for, the T-number might even be more like f/3.85 to f/3.9.

The system resolution is set by the focal ratio. The limiting magnitude and photographic speed is set by the T-number.

Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5546728 - 11/30/12 07:23 AM

Thanks for clarifying the terminology and the concepts, Mike.

I would only like to add that, commonly, the terms f-number and t-number are used interchanably, such as, for example, here, and here, and always as simultaenous change of aperture diameter with aperture area.

In reflecting optics, with few exceptions, this is not the case because the central obstructioon reduces the area but not the physical aperture, hence the need to use separate terms and concepts, as Mike explained.

Personally, I like to distinguish the concepts as geometric or absolute aperture (f-number) and relative aperture (t-number), so as to avoid as much as possible the f-number and t-number terms, given that they are frequently used interchangeably and can lead to confusion.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5548349 - 12/01/12 07:02 AM

Quote:

I like to distinguish the concepts as geometric or absolute aperture (f-number) and relative aperture (t-number)




They are both relative; f-number is routinely referred to as relative aperture alone, which is O.K. as long as we use effective relative aperture for T-stop, based on the actually transmitted light (which means it often isn't the same on and off-axis). Still, it doesn't hurt to make sure which one it is, and add to the former geometric, or nominal.

The actual relative aperture at the detector is also affected by aberrations, specifics depending on the properties of detector (e.g. pixel size w/CCD).

Vla


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: wh48gs]
      #5548441 - 12/01/12 09:03 AM

Quote:

Quote:

I like to distinguish the concepts as geometric or absolute aperture (f-number) and relative aperture (t-number)




They are both relative; f-number is routinely referred to as relative aperture alone, which is O.K. as long as we use effective relative aperture for T-stop, based on the actually transmitted light (which means it often isn't the same on and off-axis). Still, it doesn't hurt to make sure which one it is, and add to the former geometric, or nominal.

The actual relative aperture at the detector is also affected by aberrations, specifics depending on the properties of detector (e.g. pixel size w/CCD).

Vla



Thanks Vla. I was reluctant to use "absolute" when referring to the f-number (defined as focal length divided by the diamter of the objective, or F/D), but in a system with a fixed objective diameter and focal length it seems applicable and justifiable. This is why I also prefer the term "geometric".

In reflective systems, you also have fixed parameters. The F/D doesn't change with the size of the central obstruction. So, while their absolute or geomtric f-ratio remains nominally the same regardless of the size of the central obstruction, the "effective" (which is another good term, as you noted) or relative light gathering area of such systems is. This results in a smaller light gathering area or throughput of light energy which is equivalent to a smaller unobstructed aperture.

Mike prefers to use t-term for this, but as I noted, this term is elsewhere used interchangeably with f-number, which can lead to a conflation of both, and in unobstructed configurations it actually is one and the same.

Whatever term is used, it probably doesn't hurt to define it prior to using it. In Mike's example, the 10-inch light-gathering area of the mirror is effectively reduced by the central obstruction to that equivalent of a 9.25-inch unobstructed aperture, and represents the difference in the area of the mirror and the central obstruction.

Mladen


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Mike I. Jones
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5548565 - 12/01/12 10:44 AM

Just to continue, the unobscured pupil area in cm2 is multiplied by the irradiance (power density) at the entrance pupil in watts/cm2 from a given star, then by the system transmission throughput, to give the irradiance at the focal plane, also being power density in watts/cm2. This is the total irradiance contained in the system diffraction pattern; point spread function plots then give the distribution of irradiance power density in the diffraction pattern, and encircled or ensquared energy plots are used to give the accumulated power density as a function of PSF radius. Multiplying the exposure time by the irradiance gives the energy density in Joules/cm2 available to a photographic sensor. Visual limiting magnitude depends on the obscured pupil equivalent aperture, not the full entrance pupil diameter.
Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5548600 - 12/01/12 11:14 AM

Mike, wouldn't the brightness of a star appear the same in, for example, a 10-inch telescope regardless of the focal ratio?

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5549065 - 12/01/12 04:32 PM

Visually, yes, the system focal ratio does not affect limiting magnitude. The retina is a non-integrating detector, so staring continuously at an object does not make it appear brighter, unless you happen to still be dark adapting at the time.

At lower powers and large eyepiece exit pupils, though, high-brightness light pollution increases the background brightness, and can also interfere with dark adaptation, both of which affect limiting magnitude.

Photographically, the f-number and T-number directly impact photographic exposure times, as cameras are integrating detectors.

Mike


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5553474 - 12/04/12 07:37 AM Attachment (39 downloads)

I deleted my previous post, Zemax found a better design. This is a telecompressor/coma corrector for a F/5 Newt primary. It makes it an f/2.8.

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5553485 - 12/04/12 07:45 AM

Great work .Will it work for all size telescope?

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5553549 - 12/04/12 08:40 AM

Duel of the Joneseys! I'm eatin' popcorn.....
M.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer *DELETED* new [Re: Ed Jones]
      #5553868 - 12/04/12 12:18 PM

Post deleted by MKV

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Re: 10" f/3.5 Astrograph with Rosin focal reducer *DELETED* new [Re: MKV]
      #5553964 - 12/04/12 01:14 PM

Ed, could you show the spots?

Mladen

Edited by MKV (12/05/12 04:33 AM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5554430 - 12/04/12 06:43 PM Attachment (35 downloads)

Mladen,
Here is the spot diagrams. I optimized it for C,F and D so the deep blue 405 isn't so good but it could be optimized for other ranges. With 5 lenses it there won't be too many ATMs that can do this but it shows what's possible. It works with most focal length mirrors that can have enough BFL space.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5554551 - 12/04/12 08:02 PM

Quote:

Mladen,
Here is the spot diagrams. I optimized it for C,F and D so the deep blue 405 isn't so good but it could be optimized for other ranges. With 5 lenses it there won't be too many ATMs that can do this but it shows what's possible. It works with most focal length mirrors that can have enough BFL space.



Thanks Ed. Looks really nice. Obviously this type of corrector is the way to go with bigger mirrors.

For some reason OSLO didn't get the same results with your original configuration. I believe it's the limitation of OSLO.EDU to 10 surfaces, so in order to include the airgap between the two N-PSK57 lenses you'd need 11 surfaces in OSLO.

Also, I don't see why a five-lens corrector would be impossible for an amateur and a four or a three element wouldn't. It wouldn't be cheap, but results are great, and the shapes are not exotic.

Mladen

Edited by MKV (12/05/12 04:35 AM)


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: MKV]
      #5554599 - 12/04/12 08:31 PM

Mladen,
I only have 10 surfaces, seems like it should work. I've played around with this design and it can be pushed even better including 405nm.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Ed Jones]
      #5554779 - 12/04/12 10:33 PM

Quote:

Mladen,
I only have 10 surfaces, seems like it should work. I've played around with this design and it can be pushed even better including 405nm.



I just noticed that I was using a wrong glass for the third lens, so disregard any previous attachments.

No doubt the performance can be pushed even better, but what's really attractive and practical about this configuration is that the primary mirror is a relatively slow paraboloid (f/5) and therefore relatively easy to figure to high precision, yet the system operates at f/2.8.

Mladen


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: kfrederick]
      #5979155 - 07/19/13 04:37 AM

Dear Dr.Mike and Ed ALL Friends here,
I have removed the MEADE 12 inch LX200 Telescope optics.
Primary mirror is 310 mm diameter and Radius of curvature is -1200mm, Sec mirror is 75 mm Diameter and Radius of curvature is 364 mm. Distance between primary and sec is 470 mm. Any option to convert to a cass telescope of this optical Mirrors with 1 deg field or less.


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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: ismail]
      #5979526 - 07/19/13 10:17 AM

Kind of confused here, ismail. You took the mirrors out of a Meade 12 inch LX200 Cassegrain, measured them, and want to make a Cassegrain out of them, which is what they already were, in?
Mike


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hellojabil
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5979645 - 07/19/13 11:25 AM

Thanks Mike. Yes I know it is cass telescope but I would like to know the quality of the image it will have without corrector plate?

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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: hellojabil]
      #5979698 - 07/19/13 11:50 AM

Experience is the best teacher in this forum. Set them up and try it for yourself, answer your own question, then let everyone here know what you found out.
Mike


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hellojabil
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Re: 10" f/3.5 Astrograph with Rosin focal reducer new [Re: Mike I. Jones]
      #5980895 - 07/20/13 04:54 AM

Thanks Yes I am doing that. I have done the primary mirror with ronchi setup it is good sphere. I have tested the sec mirror with ZYGO Interferometer and found one fringe circular. planing for Hindle test for secondary and autocollimation test soon with combination of both mirrors. And planing to enter the values in ZEMAX. hope you can suggest any other things which i can plan for it.

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