Peter.
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Originally Posted by Peter Ward
(1 ) CSIRO's optics lab at I understand no longer has the Wyko, and gather that you no longer have access to it either ( wonder what happened to it?)
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Quote:
Originally Posted by Peter Ward
I don't think I ever contacted you over a C-8.....but was keen to get some locally made RC's happening when the $A was at 49 cents.
(2) The piece by Roland Christen I pointed to earlier very much echoes my experience in star testing optics. I have known an optic to be excellent (via test data) yet the star test was a little weird.
Imaging with the same set convinced the the test data was right all along.
( 3) Peter Ceravolo (who my liver knows well) is also adamant that what a telescope does out of focus (i.e. star test) is of far less of a concern than what it does in focus.
So I guess we'll have to agree to dis-agree  |
1. CSIRO Center for Precision Optics still have the Wyko 6000 or an upgraded model of it and use it frequently. Where exactly do you get your information from ?
2.I've never even asked for access to it or needed it in the last 10 years...and I've never claimed that I used it other than the 10 years I worked there so I'm not reallly sure what your point is there ????
I have a very nice interferometer of my own thanks ( for the last 14 years and currently upgrading it ) , and it doesn't show me anything that the knife edge and eyepiece shows clearly and quickly, I don't use it routinely, I am far more interested in monitoring the things it doesn't measure well.
3.Rolands article is specifically not on the subject I have been discussing. I refer to mirrors of high Strehl ratio by interferometry that have obviouss surface rougness and edge problems. Roland talks about weather or not to polish out high order aberrations , that customers can see in the star test. Not quite the same thing....
4. I have lots of respect for Peter. AT the end of the day, if you are wondering *why* your scope has no contrast in focus then defocus and look at the contrast in the fresnel rings.
IMHO A knowledgeable star tester can always pick a superior mirror , and an optician that pays close attention to the star test can make a better mirror. I've got 30 years of observing and 20 years practical experience in manufacturing and testing optics. I look at star images in and out of focus , day in day out. There are certainly minor aberattions that can be seen in the star test that won't affect in focus but there are many common aberrations which do effect contrast infocus , it just takes experience to know what is significant.
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Originally Posted by Satchmo
Peter, I used a Wyko 6000 Phase shifting rig at the CSIRO in Lindfield for 10 years. We had an F3 diverger lens that was quite happy testing up to 24" on the anti vibration damping bench.
Was your bum scope a C8 ?. I recall giving a quote of $400 to do the testing on the testing on the Wyko 6000 back in the early to mid 90's?
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