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Post by Watcher3 on Jan 16, 2012 16:46:20 GMT -5
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Post by istarmullet on Jan 16, 2012 18:05:40 GMT -5
I'm one of them....
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Post by Mike on Jan 18, 2012 0:20:30 GMT -5
I took delivery of 12 complete scopes recently. Most have already been shipped to customers. I have 25 more coming next month and some of those are spoken for. Get the picture? We WILL pursue the Raycorr this year. Actually, the design is sound as it is. It is just a matter of the right glass. The wrong glass is what brought the project to a screeching halt. Believe me when I say we are just as anxious to get the Raycorr into production as you are. Brisk telescope sales are what will finance the project.  |
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spyke
New Member
Posts: 7
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Post by spyke on Jan 18, 2012 18:08:39 GMT -5
Very glad to hear that the Raycorr is still on the cards. I look forward to reading more about it - any pre-release information will be drooled over by a lot of people. I have a rather nice 6" f8 Helios that I feel would benifit from the Raycorr when it becomes availablke, so I'm watching this pro9ject with keen interest.
Thanks, Ant
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Post by tonybegg on Jun 21, 2012 1:46:36 GMT -5
Ales - I found myself looking into the background of Chromacorr and Raycorr designs and it seems the first reference to such an idea (a smaller lens nearer the eyepiece to correct longitudinal CA of an ordinary Fraunhofer Achromatic Doublet objective) was a design by Roland Christen in October 1985 Sky & Telescope which I downloaded to read the article. In that (presumably prior to his Astro-Physics days but I don't know) he designs a 10 inch f/14 refractor with a 3.5 inch (certainly bigger than the Chromacorr) triplet consisting of Corning B58-53 crown, Schott KzFS-NZ flint and Schott BaK-5 crown with (from the drawing) quite steep curves but spherical. So, knowing you are having lousy luck with obtaining exotic glasses for Raycorr, have your optical designers seen how far they can go towards the theoretical Raycorr performance using readily available glasses? I think even if you made a half-way decent Raycorr wanna-be it would increase the sales of your faster achromatic telescopes. And then maybe you might be able to make the big orders of exotic glass. Just a thought - might be barking up the wrong tree here. Best Wishes Tony
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Post by Watcher3 on Jun 21, 2012 7:51:29 GMT -5
Tony. I believe the Roland Christian device you're talking about is the tri-space corrector. If you hunt around on CN, you can find several references to it. VERY expensive, and very coveted by those few who own them.
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Post by mikey cee on Jun 21, 2012 9:25:57 GMT -5
Sounds like I'll be waiting for the cows to come home for my Raycorr for the F/11 model. Wa wa:'(  |
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Post by Watcher3 on Jun 21, 2012 21:05:03 GMT -5
That's OK Mikey. The cows always come home before dark!  |
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Post by tonybegg on Jun 21, 2012 22:14:09 GMT -5
It is the Tri-Space as you point out. Here is the full design from S&T:
Specifications in inches:
The Fraunhofer doublet (10 inches, f/14) has a 0.2 inch air-space:
1. Schott K-7 crown, diam. 10.4, thickness 1.00, R1 +82.0, R2 -51.0
2. Schott SF-2 flint, diam. 10.4, thickness 0.45, R3 -51.85, R4 -194.0
The Tri-Space Corrector (placed 91 inches from surface 4, total thickness 1.5 inches, distance to focus 46.6 inches:
3. Corning B58-53 crown, diam. 3.5, R5 -22.4, R6 -4.0
4. Schott KZFS-N2 flint, diam. 3.5, R7 -4.0, R8 +16.0
5. Schott BaK-5 crown, diam. 3.5, R9 +16.0, R10 -21 .5
The point I was trying to make was that there might be a way to get closer to the Raycorr concept using less exotic glass, and given that both Valery at Aries that makes the Chromacorr and Ales of IStar are having problems obtaining the ideal glass perhaps it might be worth looking at less ideal designs. In the article Roland says he designed a 10 inch Tri-Space to correct the Yerkes 40 inch.
Tonight I am reading James G Baker's (of Baker-Schmidt fame) article "The Catadioptric Refractor" in which he is suggesting the Schupmann Medial approach to correcting the Yerkes 40 inch. This involves a "mangin mirror" (a back-silvered lens) and some awkward off axis light paths it seems and the color correction (and other aberration corrections) seems to arise from effectively reversing the light path (haven't fully grokked it yet). My interest is of course in correcting the IStar scopes and I am just wondering if a team as innovative as Ales and his optical designers cannot solve this problem taking a different route than Raycorr, one not beholden to the glass manufacturers. Not abandoning Raycorr but just looking at other ideas.
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Post by Mike on Jun 24, 2012 17:35:58 GMT -5
Tony, Getting the correct glass has not become an impossibility yet. Actually we have two companies, one right here in the US, that we may be able to get the correct glass from. While it may be true that a design can be "compromised" by using less exotic glass, the end result would be equally compromising. We will continue to pursue the original design. If this goes down as planned, we will "wow" the crowd. It won't be released until it's perfect. There are a lot of naysayers, to do anything less...
Mike
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