[ATM] Re: Second Thoughts on Mirror Support

[gseronik at netway.com (Gary Seronik)]

At 08:06 AM 2/11/2004 -0500, Emery Greg wrote:

"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."

Dobson built his mirrors with porthole glass, which is I believe only 1"
thick or thereabouts.  Certainly not full thickness in any case.

I may be wrong on this but I don't believe Dobson used carpeting to support
his mirrors, as I have seen asserted here a couple of times.  The scopes I
have seen by Dobson all had 9-point floatation cells, albeit, made from
simply materials.  On the occaisions I've heard him speak on the subject, I
don't recall him advocating the use of carpet for mirror support in the
telescope either.  Possibly this idea comes from someplace else or is based
on the assumption that if it's okay to support a mirror on carpet when
grinding, it must be okay to do so in the scope.

Regards,
Gary