Quote:
Originally Posted by DavidU
I know what your getting at Eric. A mirror test, teste the whole surface.
So if it was a perfect parabola just off center, the gross error from the off set side would translate into an astigmatism.
Here you see some Ronchi screens, just imagine what they would look like if the patterns were all to one side
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But if I wasn't going to do a Ronchi test of, say, my humble little GSO 12 mirror, would star testing tell me quickly if I had one of these wonky mirror problems?