Quote:
Originally Posted by matt
When I say 1/12th wave, I'm assuming they are referring to the same measure as Celestron refers to when they guarantee their SCTs to be at least 1/4 wave and GSO when it refers to its mirrors being 1/12th wave.
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I would guess that that they mean 1/12 RMS surface accuracy as they claim 1/16 RMS surface for their Newtonian mirrors which are far easier to make than the highly aspheric RC's.
You can see the Newt specs here:
http://www.gs-telescope.com/content.asp?id=95
1/12 RMS equates roughly to 1/3 PV wavefront, and 1/16 RMS is 1/4 PV wavefront. If these tests are done at 632mm HeNe laser wavelenghth then increase those figures by about 20% for wavelength at peak visual sensitivity.
I don't see the point of talking about surface accuracy on a mirror as it can only produce an optical wavefront upon reflection.