[ATM] astigmatism update

[Jeff Baldwin]

Hi gang;
I'm the one who posted the original issue. Here's my update.

I've tried a carpetted plywood with a sling at 140 degress, I moved the sling to 180 degrees, I've replaced the carpet with a 9-point flotation I derived off of PLOP, I've replaced the sling with a wire (180 degrees), and I've replaced the wire with two pegs at 90 degrees. I still have a longer ROC for the vertical diameter than for the horizontal diameter.  Furthermore, I would have expected the mirror to relax vertically producing a shorter ROC on the vertical diameter than for the horizontal diameter, which is NOT the case. This must mean that the mirror is falling back, not leaning forward. My next trial will be with a formica style countertop board behind with two pegs, but I'm also thinking that the mirror will seek out 3 primary points of force against it. But I'm willing to try it. How, then, would I deal with this in my telescope??? I'm not going to put formica countertop in my telescope, I hope.

Thanks to all who have tossed in on this, both serious and silly. After 300 mirrors, I'm not a total newbie, but am perplexed by this particular project. This can't be entirely that the mirror is too thin, many of you guys have been doing mirrors with higher aspect ratios than my 18:1 and have done so without the test stand destroying your information. Thanks again everybody.
Bald

Jeff and Glenda Baldwin
Lathrop, CA
www.stocktonastro.org