[ATM] is mirror thermal equilibrium important

[Alexis Cousein]

James Lerch wrote:
> I have a 2" fan blowing directly across each secondary, and it has a LOT 
> of air flow, but it still dewed over.  Here's a picture:
> http://lerch.no-ip.com/atm/UpperFan.jpg
> 
> Prior to this years dew heater upgrade, dew would form first on the 
> secondary, then by midnight it would be forming on the primaries.  I 
> have plenty of ambient air flow over each optic.  So much so a comment 
> was made by a fellow observer one night that "The wind keeps changing 
> directions" :-)

Darn! The air must be pretty close to 100% relative humidity. Well, you
have much better seeing than we do, and we can't fix our seeing with a few
resistors ;).