[ATM] Cooling of a primary Mirror

[Arjan te Marvelde]

Russ wrote:
> the alunimum coating, I must say I agree.  The Aluminum coating on glass
is
> so thin that it has
> almost a null effect on heating or cooling. Think about it, your mirror is

Well, I'm not so sure about this reasoning. Ever heard of low emissivity
glass? This is glass that has an even thinner coating of metal, which lets
light enter the room, but does not radiate heat as much as uncoated glass
would.
If this holds for buildings, it means that the telescope mirror would as
well loose less heat from front than from back side, at least, where
radiation is concerned. I don't know which portion of total heat loss is
caused by radiation though. Using fans may shift the balance to convection
loss.

/Arjan te Marvelde