Re: [ATM] 8" Diagonal

["Tom Krajci" <tom_krajci@tularosa.net>]

>From: Polaraligned <polaraligned@optonline.net>

>Can anyone offer me an opinion on how thick an
>8" diagonal should be?  Is 1.5" enough?
>Also, is silicone with safety clips the best bet for
>mounting? or is it too big for that.

My sixteen inch, 1.5 inch thick main mirror is held on with six pads of RTV
silicone, no edge clips/etc.  After I glued it and let it cure several days,
I tested it by grabbing the mirror cell and gradually shaking it more and
more vigorously...until I was practically trying to do the hammer throw with
it and the 25 pounds of glass glued to it.  If you are careful in cleaning,
applying, and curing RTV silicone, it will be strong enough.  Go look at
aquariums and think about the loads the RTV silicone bonds must handle in
that case.

I can't answer your other question until you tell us how it will be
supported, and what material it will be made from.

Pyrex?  Fused quartz?  Plate?

If you use RTV silicone you can use an upside down whiffle tree.  With
enough supports in the system...you can get by with a pretty thin 8"
diagonal...assuming an optician is willing to make it that thin for
you...that may be the limiting factor.

I hope this helps.

Tom Krajci
Cloudcroft, New Mexico
http://overton2.tamu.edu/aset/krajci/



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