[ATM] Re: Second Thoughts on Mirror Support

[greg.emery at mohawkcollege.ca (Emery Greg)]

Hi Geoff:

Didn't Dobson originally design his mount to be easy to use as well as to be able to be constructed from common materials by a typical person?  

If this is true, the carpet support support is a common material which doesn't require specialized tools or knowledge.  I believe ( on thin ice here) that Dobson's design also had full thickness mirrors which allowed for greater latitude in mirror support/cell design.

ttfn
greg

----- Original Message -----
From: gjnelson@absamail.co.za
Date: Wednesday, February 11, 2004 7:05 am
Subject: Re: [ATM] Re: Second Thoughts on Mirror Support

> > The original John Dobson style scopes use carpet, not wiffle 
> trees 
> to
> > support the mirror.  Thus it does appear to work to some (as yet
> > unquantified) degree.  Think of  it as a 10000 point variable force
> > cell.
> 
> 
> This is a compliant support. Where you have the most force you 
> have 
> the most give thereby increasing the area of support and reducing 
> the 
> point forces. This would give you instead of three points of 
> contact 
> three areas of contact that would essentially merge not each other 
> seamlessly dependent on how flat the support of the carpet is.
> 
> I guess it could be modelled in PLOP but setting it up or even an 
> approximation of it would be quite a challenge.
> 
> Now what would happen if you RTV'd the mirror to the carpet? No 
> sling 
> would be required and you will still have a large support area. 
> 
> Geoff
> 
> 
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