| Cary |
| (Vendor (Optic Wave Labs)) |
| 07/03/09 03:14 PM |
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Test Setup for Cass using a Parabola
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Hello,
I'm looking for a layout / ZEMAX prescription for a Cass test setup using a long focus parabola. Any help here? I know there are a couple of ZEMAX brainiacs that could spit this out in a second.
Thanks,
| DAVIDG |
| (Carpal Tunnel) |
| 07/03/09 03:18 PM |
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Re: Test Setup for Cass using a Parabola
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Are you trying the test the secondary or the complete scope? Also what size cass and what size parabola and what is it focal length ?
- Dave
| Cary |
| (Vendor (Optic Wave Labs)) |
| 07/03/09 03:48 PM |
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Re: Test Setup for Cass using a Parabola
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Whole scope....
| DAVIDG |
| (Carpal Tunnel) |
| 07/03/09 04:49 PM |
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Re: Test Setup for Cass using a Parabola
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All you do is put a small light, like a LED at the focus of the parabola. The light coming off the parabola is now parallel, at least in theory. You then aim the cass. at the parabola and either knife or ronchi test at the focus of the cass.
The parabola has to be of very good quality, since any error in it will also add into any error in the telescope under test. The parabola should be as large or larger then the 'scope your testing but if it's smaller you can move the cass. so the edges then the middle are illuminated and get a good feel for thr over all correction.
- Dave
| Cary |
| (Vendor (Optic Wave Labs)) |
| 07/03/09 05:35 PM |
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Re: Test Setup for Cass using a Parabola
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As I mentioned before, I'm looking for help getting the test into ZEMAX. Not just theory.
| Ed Jones |
| (Pooh-Bah) |
| 07/03/09 06:25 PM |
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Re: Test Setup for Cass using a Parabola
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What are you looking to do specifically?
| Mike I. Jones |
| (Carpal Tunnel) |
| 07/03/09 07:37 PM |
| Attachment |
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Re: Test Setup for Cass using a Parabola
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Something like....this?
12.5" f/4 parabola, fed at its focal point by a single-mode fiber with an LED at the other end. Cassegrain, Mak, refractor, or anything else can now be placed in collimated light for testing.
Ehh?
Mike
| Mike I. Jones |
| (Carpal Tunnel) |
| 07/03/09 07:39 PM |
| Attachment |
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Re: Test Setup for Cass using a Parabola
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The ZMX file is attached.
Mike
| Cary |
| (Vendor (Optic Wave Labs)) |
| 07/04/09 02:56 AM |
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Re: Test Setup for Cass using a Parabola
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I had a feeling Mike would come up with it. Thanks!
| Mark Harry |
| (Post Laureate) |
| 07/04/09 08:29 AM |
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Re: Test Setup for Cass using a Parabola
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Nothing of "theory" about it. Basic idea, it's a Newt aimed at a Cass. You have to validate the quality of the Newt to a good high degree, and the F/D doesn't matter. Dave was correct. Carrying it a step deeper-
What -DOES- matter, is the quantification accuracy desired!!!!!!!! That requires iterations that ZEMAX can do easily. Along with our 2 'MAX designers.
(Did I get it right, Mike? If not just tell me to shut-up.)
Mark