Re: [ATM] 20incher with segmented and ribbed mirror at 12Kg

[Ric Rokosz <radicell2@yahoo.com>]

--- Andreas Derwahl <andreas@duda-derwahl.de> wrote:

> Hello all
> 
> In a recent discussion on the German ATM newsboard
> astrotreff.de the dutch
> amateur Willem van Nood has introduced his
> experimental 20 incher with a
> segmented and ribbed mirror:
> 
> Though you probably cannot call this experimental
> scope a complete success
> at this stage, as it delivered worse images and
> contrast than the 10 incher
> also present at first light, I feel it might be of
> interest to this list
> nonetheless, especially for the "boundary pushers".

It might be a new idea over in Europe,but there are
several of us here in the US and Canada that have been
doing fused ribbed glass for decades now(!).Strange
how each new generation needs to learn that gluing
doesn't work .Had he Frit bonded the pieces he might
have had a chance.Some mirror coaters give a mirror a
slight pre-heat before coating the mirror and that may
have distorted the glass back to a sphere,plus if the
annealing was not done properly that too would have
added a factor in the shape change.

Look at:
 http://wwww.geocities.com/radicell2

for another layout scheme that does work in many ways
critical for success.

Ric




 
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