Re: (ATM) ATM planetary scope window
PFAFF2@delphi.com
Tue, 22 Aug 1995 22:41:02 -0400 (EDT)
> > Now this seems to be a tall order in a window of any size: sideways heat
> conduction will be very slow, so it will only stay at a uniform temperature
> throughout if whatever cools it during the night acts uniformly across it.
> One might need a "stirrer" within the tube that could be switched on from
> time to time to blow air over it and even out the temperature!
>
> Has anybody any experience of this effect? Is it actually a problem? Does
> refractive index change with temperature and cancel out the wavefront errors?
>
> Roger Moss
>
>
>
Well maybe. At RTMC this year I was looking thru Jerry Logan's
10" folded Schupmann at a 1.5 sec double star. I could not split it.
Jerry turned on a fan at the bottom of the tube. The air enters at
the top of the tube around the lens cell and is expelled at the bottom
of the tube. As soon as the fan was turned on the double split with
a dark space between the stars.
Bob Pfaff