Re: [ATM] Primary cooling fan

[Mark Holm <mdholm@telerama.com>]

Russell Jocoy wrote:
> 
> Question... will this affect my image at the
> eyepiece??

Alder, Alan, Thermal Management in Newtonian Reflectors, Sky &
Telescope, Vol. 103, No. 1, January 2002, pages 132 - 136

Greer, Bryan, Understanding Thermal Behavior in Newtonian Reflectors,
Sky & Telescope, Vol. 100, No. 3, September 2000, Pages 125 - 133

Greer, Bryan, Improving the Thermal Properties of Newtonian Reflectors -
Part 1, Sky & Telescope, Vol. 107, No. 5, May 2004, Pages 128 - 132

Greer, Bryan, Improving the Thermal Properties of Newtonian Reflectors -
Part 2, Sky & Telescope, Vol. 107, No. 6, June 2004, Pages ? - ?

Video examples from Bryan Greer's article are available at
http://skyandtelescope.com/howto/scopes/article_1182_1.asp
or at
http://www.fpi-protostar.com/bgreer/may2004s%26t.htm This second link
has more content than the one at S & T.


According to above, front blowing fans not only cool the mirror
effectively, but also improve images even before the mirror reaches
equilibrium.  One potential downside is vibration from the fan.  Some
fans are supposed to be smoother than others.  I don't know which.

I don't know about a fan's effect on dewing.  I sort of recall someone
writing that a fan helps retard dew, but am not sure of it.

-- 
Mark Holm
mdholm@telerama.com

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