Re: [ATM] astigmatism as seen via ronchi?

["Mitchell R" <funnybone101@embarqmail.com>]

How can that be?. The mirror has no knowledge of what is up and what
is down, or of gravity. Do you actually mean to check that the grating
is parallel to some other reference?

-- 

I believe he means just close to up and down, it is harder, but my no means
impossible, to Ronchi test sideways. (I believe you can check for astig this
way too, rotating the grid?).

If everything is opposite on opposite sides of ROC it make sense that if it
is tilted one way it will look the opposite on the other side of ROC. 

Mitch

_______________________________________________
ATM mailing list http://www.atmlist.net/