Quote:
Originally Posted by Atmos
Before loosening the mirror clips the stars looked more like triangles, this I assumed was astigmatism (mirror stress).
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Correct, trefoil astigmatism.
But be careful with the terminology.
Not all instances of mirror stress result in astigmatism.
Not all astigmatism is the result of mirror stress.
^^^ These are two very different statements.
Quote:
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What you’re saying though is that the astigmatism is noticeable in our of focus, I’ll have to do some more testing when I’m at my dark site and have a few hours... and a few screw drivers Hehe
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You may want to re-read that sentence, I'm finding it difficult to parse.
If you are asking whether (classical) astigmatism is most obvious just either side of focus?
then yes, that is correct.
It will look like this:
http://slideplayer.com/slide/9437250...stigmatism.jpg
You're welcome.
~c