Re: ATM Adding a fan to an SCT - some lessons learned

["Tom & Lou Krajci" <krajcit@3lefties.com>]

From: astrojoe@erols.com

>I did this with my C 9.25" a few years ago. I only drilled out the rear
>casting to have a filtered intake. I mounted a small fan to a piece of
>delrin I machined that slipped into the 2" rear back. Turned on the fan
>to cool down the ota in 20 minutes. Without it, cooldown time was 2.5
>hours and counting....

>http://www.myhomeis.com/jcscope3/

Thank you for the pic's!  My C-11 is pretty old...the rear casting is not
flat like your C 9.25 or newer C-11's.  It's ribbed and convex.  I don't
know if the older casting is less rigid, or if they changed some things in
the focuser/baffle tube/mirror cell.  One of these days I'd like to see the
innards of these newer models.  Maybe I'll figure out how to reduce flop and
flexure in mine that way?

Hmmmm, maybe I can find a telescope junkyard that has a late model C-11 rear
casting for next to nothing?  ;-)

Tom Krajci