Re: ATM 8" mirror questions - weight, good sources, mirror cells?

[santryl@cadvision.com]

>1) How much is a "standard" 8-inch mirror going to weigh?

   Our unmounted full thickness pyrex mirror weighs (in archaic King's 
Imperial Measure) five pounds.

>2) I'm considering an approximately f/7 primary - what do people think 
>of this in terms of both optical quality and mechanical considerations? 
>Seems to me that that would allow a fairly reasonable tube length (and 
>hopefully somewhat reasonable mirror price as well).

   Well!  I was forced by design criteria and space to go with an f6 and 
I love it.  An f7 would be even better, smaller diagonal, etc.

>3) What is a good place to get a nice 8-inch mirror? I've heard enough
>nice things about Galaxy that I just called them - and was told they 

   Do you want the very best?  Barry Arnold of Arnold Optics, 433 Sioux 
Road, Sherwood Park, Alberta, T8A 4H2 (403)467-4781 makes excellent 
mirrors.  Our 20cm f6 mirror cost 450 Canadian, for primary and matching 
secondary, last spring.  With a U.S. dollar buying about 1.3 Canadian 
ones, you can get quite a deal on a premium product.

>4) The Tectron pamphlet really stressed the importance of a good mirror
>cell. Is this still a significant thing down in the 8" range, or is
>Berry's silicon-and-wood mount just as good? Who sells decent 8" 
>9-point flotation cells? 

   While not quite as important, a good cell makes everything easier.  
You can get a quality nine point cells from Kenneth Novak, Box 69, 
Ladysmith, WI 54848 (715)532-5102 weekday afternoons.
   Clear skies!
               MK