Mirror thickness...

I am comimg up with a center thickness on this mirror to be roughly 1.15 inches thick, not being an expert on mirrors, can someone tell me how that impacts overall rigidity and overall optical performance given the 32 inch diameter? Or is that thickness ok ?(Or did I miscalculate? I did the numbers in my head).

http://www.astromart.com/classifieds/details.asp?classified_id=623697

I have viewed with Steve Kennedy's 32", 28" and 24" mirrors and all have worked really well. The proper mirror cell will handle it without issues.
His mirrors are really something, to me possibly the best large mirrors made.

Tony Aguire said:

I am comimg up with a center thickness on this mirror to be roughly 1.15 inches thick, not being an expert on mirrors, can someone tell me how that impacts overall rigidity and overall optical performance given the 32 inch diameter? Or is that thickness ok ?(Or did I miscalculate? I did the numbers in my head).

http://www.astromart.com/classifieds/details.asp?classified_id=623697

Tony:

The formula for the Sagitta of a Parabolic mirror is:

Sagitta = r2/2R

where r is the radius of the mirror
and R is radius of curvature.

Since the radius of curvature is twice the focal length, the Sagitta for 32 inch mirror with a 116 inch focal length 0.55 inches. The edge thickness is 2.25 inches so the center thickness is actually 1.70 inches.

http://astro.umsystem.edu/atm/ARCHIVES/JUL01/msg00958.html

As far as the maximum field of view for such a mirror, assume one is using a Paracorr and a ~7mm Exit pupil. At F/3.625 this computers to a 29mm focal length eyepiece. Choosing the obvious 31mm Nagler, the field of view works out to be about 0.86 degress with an 7.4mm exit pupil. Not exactly spacious but surprisingly this is the about the same maximum TFoV as an ETX-125. The 28mm Uwan would provide 0.76 degrees with a 6.7mm exit pupil.

jon