[ATM] Sling study

[Mel Bartels]

> >This table is based on my experience with one thin mirror.  Note that Mel
> >Bartels once did an 8" x 1/4" mirror, so his thicknesses would be about
> >2/3 of mine.


For that matter, John Walley, a super mirror maker and teacher of mirror
making classes for literally decades, often would have his students use 8
inch diameter x 3/8 inch thick plate glass.  John made a thin 18 inch before
the Dobson era.  There were those out there working in the field of large
thin mirrors without subsequent notice from the ATM community.  BTW, John
also experimented with extremely high magnifications, sometimes up to 200x
per inch of aperture.  He had extremely magnified eyepiece projection images
of Saturn and Uranus from the very old black and white film days in the
1960's that were stunning for their era (images that occupied 1/2 of a 35mm
film size and that were guided for minutes at a time).  He also
self-published a book on telescope making optics that included chapters on
grinding lenses for refractors and eyepieces.  

Mel Bartels