Re: ATM Questions

[Anthony Stillman <atmer@flash.net>]

Ken and Teresa,

When testing the group 70 mirror, we have on occasion left the mirror
vertical for several hours.  On those occasions a thermal gradient has
developed in the glass.  Thermal distortion was visible in the foucault
between the bottom edge of the glass (about 6" from a cement floor) and the
top edge of the mirror six feet higher.  Clearly this won't be a problem
for the average amature's test set up, I've never seen this with any of my
mirrors, but it might be a consideration for those working larger glass.

Anthony