ATM How to make a heat coil fix your figure...

[Adam Perkins <scopeguru@yahoo.com>]

Olle Erikson wrote:


> >Hello everybody
> > 
> >  How many Ah would you
> recommend a 
> > battery cell
> > to have for the fan and the heating device?

> > 
> > Sincerely
> > Olle Eriksson



Hi,

If you're thinking of a fan AND heating element on your primary, there
is an excellent Sky and Telescope article you should track down.  3-4
years ago, there was an article about using a fan to cool parts of your
mirror, and resistors to simultaneously heat others.  The resistors
were connected to a pot which allowed their heat output to be adjusted.
 The resulting differential expansion of zones of the mirror allowed
the mirror's figure to be "tweaked" during the star test.  

Maybe this is more than you want to get into on this project, but is
food for thought about where you are going to mount your heating
elements, or if you really want them on your primary at all.

I forget the issue #, but can dig it up if anyone asks...

Adam Perkins
Covington, Louisiana


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