Re: ATM 16" blank thickness extended question

[Krajci Tom J Maj 27OSS/IN <Tom.Krajci@cannon.af.mil>]

From: brauch <a.brauch@okay.net>

>...my question is now, how much is the =
>increase of effort and the risk to end with a not so good mirror when =
>using thin instead of thick material ?

My sixteen inch mirror is 1:10 thickness ratio.  That's a thin blank by old
standards, but by new (at least with ATM'ers) standards that's not really
very thin.

I had no problems with astigmatism in figuring the mirror, and it is
supported in its cell on only six points, with no detectable image
degradation.  (Based on that alone, maybe we should label 1:6 thickness
ratio mirrors as "excessively thick."  ;-)

I do not know how thin the mirror blank is that you are considering buying,
but with care, you should not have problems with a 1:10 ratio in a sixteen
inch size...and the finished mirror will only weight about 25 pounds.

Good luck!
Tom Krajci