Re: [ATM] Re:Tees instead of triangles

["Alan K. Henderson" <alankh@ev1.net>]

It's a finished mirror, not a blank. I suspect it used to belong to an old
equatorial. I know that at least two companies sell 16" equatorials with
full-thickness mirrors - Meade (model may be discontinued) and Parks
Optical.

I'm using this idea to address the thermal problem:

http://www.balinka.com/portfan.htm

Instead of using a homemade power supply I got this:

http://meade.telescopes.com/products/Celestron_Power_Tank_17_12v_Power_Supply_17_Amp_Hour_25803.html

That built-in flashlight could put green lasers to shame :-)

Alan K. Henderson


----- Original Message ----- 
From: "Ken Hunter" <atm_ken_hunter@yahoo.com>
To: "Mark Holm" <mdholm@telerama.com>; <alankh@ev1.net>; <atm@atmlist.net>
Sent: Wednesday, May 18, 2005 9:35 AM
Subject: Re: [ATM] Re:Tees instead of triangles


> With a 3 inch thick blank, thermal equilibrium is
> going to be a much worse thing to worry about than
> cell induced deformations... Ensure that the blank has
> either a controlled environment (cooled to expected
> nighttime temps) or active cooling that tracks the
> current temp.
>
> We had 16 inch scopes on Kitt Peak that were unearly
> unusable (except by ATM's and visiting guests that
> didn't know any better) that are the same dimension as
> your blank. You might consider splitting the blank
> into 2 but that would require refiguring of the
> surface if it is a finished optic already.
>
> Ken Hunter
>
>
> --- Mark Holm <mdholm@telerama.com> wrote:
> > > I received an email suggesting that my mirror is
> > so thick that a 6-point cell will suffice.
> >
> > Yes.  Sorry, I didn't have much time, and didn't
> > look at your mirror
> > dimensions.
> >
> > 6-points is plenty.  The number to watch is the RMS.
> >  Anything less than
> > 1/200 is in safe territory.  Actually, the 16x3 has
> > lots of safety.
> > Your slightly larger diameter won't be a problem.
> >
> > Run Plop for the 6-point design with your
> > dimensions, and you will be fine.
> >
> > -- 
> > Mark Holm
> > mdholm@telerama.com
> >
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> >
>
>
>
> Yahoo! Mail
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>
>
>


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