Re: [ATM] fans

["Don Clement" <clement.focuser@verizon.net>]

> My fan blowing across the front of the mirror is almost a waste. Since the
front of the glass is insulated with aluminum the fan takes forever to cool
the mirror. Sure, it does a wonderful job of homogenizing the boundary
layer, but this is only a benefit while the mirror is cooling. It is better
for me to turn on the main fan blowing on the back of the glass. This cools
the mirror more quickly. And guess what? Since the back of the tube is
almost closed off for light baffling, the back fan has little trouble
homogenizing the boundary layer on the front of the mirror.
>

How do you know that you were homogenizing the boundary layer in front?  How
did you measure this? If you were not really homogenizing the air in front
of the mirror, then I agree , the fan blowing across the front would appear
to be  almost a waste.

Don Clement
Running Springs, California

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