Re: [ATM] Gluing this mirror

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

>From: Mark Holm <mdholm@telerama.com>

>Off-list, I have an inquiry from an atm who is considering a 6 point
>Plop optimized cell for this mirror:

>primary mirror diameter 305mm, thickness 48mm (Zerodur), focal length
>1136mm (f/3.72)

>He wants to silicone the mirror to the cell and is a little worried over
>the possibility of deformation due to torques when the mirror is off
>vertical.  He anticipates doing a fair amount of viewing near the horizon.

>Would those of you that have done similar cells care to hazard a guess
>whether this one will have excessive deformation.  I do not know what
>structure the plans.  Obviously, to minimize torques, it needs to be
>kept as short as possible.

My 400mm (16 inch) mirror, 40mm (1.5 inches) thick, is glued to a six point
support.  I have never noticed problems with image degradation from cell
induced deformations.  My mirror is larger and thinner (and less stiff) than
his.  I doubt that he will have problems unless his cell is very 'tall' in
design.  (My design is essentially a copy of what's described in the
Kriege/Berry book.)
http://www.willbell.com/tm/dobtel.htm

Also, if observing near the horizon...his airmass is higher than 2 or 3.
His seeing will not be very good down there unless he's at a world class
site.

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



-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.371 / Virus Database: 267.13.13/197 - Release Date: 12/9/2005

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