RE: ATM astigmatism with a sling?

["Mel Bartels" <mbartels@efn.org>]

>>>
Sorry, but I don't get how the 'stig is oriented? Does the mirror have a
shorter radius of curvature along the vertical diameter than along the
horizontal (which I would expect of a mirror stood on the edge) or the
other way (meaning the side-to-side forces from the sling are more than
it takes to compensate the first kind)?
<<<

The former, I believe.

>>>
But can it transmit force perpendicular to the plane of the mirror -
lift or press down some part of the mirror edge? Seems even soft slings
may, unless there is a soft free part between the leaving the mirror
edge and the bolt that holds it.
<<<

Yes, unfortunately.  That's why I use the low friction support blocks
now.  But after reading Wilson again, I may try a wire sling next time
around.

Mel Bartels