Quote:
Originally Posted by glend
Here is a question for a rainy weekend. I while ago I saw a comment in a thread here that suggested that mirror quality in a newtonian was not of concern when it is used for imaging, as opposed to those used exclusively for visual observation. Can anyone elaborate on that statement? Is this true or false? Do mirror upgrades have any benefit for imaging Newts? I'll assume that they also get some visual use as well.
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To have diffraction limited results = 1/4 wavelength accuracy at the CCD chip-
you need a Newtonian with at least a 1/16 wave rms primary & secondary.
The light comes in & hits the 1/16th wave primary.
It's reflected wave equals 1/8th accuracy.
It then hits the secondary as 1/8th accuracy & reflects to the
CCD chip or eyepiece as 1/4 wave accuracy.
This is just enough to give full diffraction limited results.
Note: some of the now ( no longer produced ) RCOS scopes were ion milled to 1/100th wave accuracy.
To answer your question - good optics do matter.