[ATM] is mirror thermal equilibrium important

[James Lerch]

----- Original Message ----- 
From: "marinus van der Lugt" <lugt at xs4all.nl>

> Seems to me that you are also breathing into the direction of the  secondary?
> It will be aimed below it, but might it not also rise up?

The fans are situated so that the "breeze" is down and away from the center of 
the scope (if pointed at 45 degrees elevation)

For instance, see this image:

http://lerch.no-ip.com/atm/Bino_1.jpg

You can see the left OTA secondary fan just peeking out from below the top ring. 
So the left OTA fans blow from top right to bottom left (down and away from the 
observer),  The right OTA is opposite, blowing from top left to bottom right.

Also, before anyone asks, no I haven't seen any problems with observer heat 
plumes causing image distortion.   The only problems I have at high power are 
getting the IPD to easily and accurately make minute adjustments (the top ring 
rotation mechanism needs improvement with new cast AL rings on the drawing 
board).

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)
http://lerch.no-ip.com/ChangFa_Gen (My 15KW generator project)

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