Re: [ATM] Mirror cell design

["Jeff Anderson-Lee" <jonah@cs.berkeley.edu>]

Rubber and air gaps insulate, and one problem with mirrors (other than 
zerodur) is that uneven cooling changes the figure of the mirror.  If 
the mirror can only cool from the front because of insulation on the 
back, the problem is exacerbated.

I suppose you could use a water filled bladder and circulate the water 
to speed cooling, but then you might find that the mirror shifts or 
vibrates due to the circulation.

Jeff

Guy Brandenburg wrote:

>Though I don't hear of anybody trying Leon Foucault's
>1859 innovation, of having a little inflatable rubber
>bladder sitting underneath the [thin] mirror, which
>the observer can either blow a bit more air into, or
>else let a bit more air out of, as conditions warrant.
>You have the tube long enough so that you can blow in,
>or let out, the air while you are at the eyepiece.
>Sounds like something worth trying, to me.
>  
>

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