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Cary
Vendor (Optic Wave Labs)
Reged: 07/07/04
Posts: 395
Loc: Rancho Cordova, CA
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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,
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Cary Chleborad
http://www.opticwavelabs.com
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DAVIDG
Carpal Tunnel
Reged: 12/02/04
Posts: 1962
Loc: Hockessin, De
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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
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Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schief. 60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4.5" f/16 Schupmann Medial refractor, 14 Stellafane awards 7 in optics
Engineering = Taking what you have and making what you need.
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Cary
Vendor (Optic Wave Labs)
Reged: 07/07/04
Posts: 395
Loc: Rancho Cordova, CA
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Whole scope....
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Cary Chleborad
http://www.opticwavelabs.com
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DAVIDG
Carpal Tunnel
Reged: 12/02/04
Posts: 1962
Loc: Hockessin, De
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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
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Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schief. 60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4.5" f/16 Schupmann Medial refractor, 14 Stellafane awards 7 in optics
Engineering = Taking what you have and making what you need.
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Cary
Vendor (Optic Wave Labs)
Reged: 07/07/04
Posts: 395
Loc: Rancho Cordova, CA
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As I mentioned before, I'm looking for help getting the test into ZEMAX. Not just theory.
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Cary Chleborad
http://www.opticwavelabs.com
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1394
Loc: Sin-sin-atti
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What are you looking to do specifically?
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Ed Jones
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Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1533
Loc: Fort Worth TX
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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
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Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1533
Loc: Fort Worth TX
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The ZMX file is attached.
Mike
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Cary
Vendor (Optic Wave Labs)
Reged: 07/07/04
Posts: 395
Loc: Rancho Cordova, CA
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I had a feeling Mike would come up with it. Thanks!
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Cary Chleborad
http://www.opticwavelabs.com
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Mark Harry
Post Laureate
Reged: 09/05/05
Posts: 3086
Loc: Northeast
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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
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So many projects, so little time!
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