[ATM] Ultrathin mirrors, a grinding machine

[vorblesnak@peak.org]

Tony Gondola wrote:

> What advantage are you gaining by replacing the standard overarm and
spindle
> with the Hindle type frame?

> Tony

Easy access to the plate mostly.  I have discovered that if I fill the
plate with water it will pull off the heat generated by polishing.  This
stops the distortion inheirant in the thin glass.  The pie p[ate is about
1/8th inch thick across the bottom.  The water also provides a uniform
weight mass.  In many ways it is preferable to the lead shot I used.  It
could be that a combination of lead shot and water will be the best
answer, but then the lead corrodes.

The Hindle alligator allows me to add water if I slop and controls the
plate from the top edge of the plate, with no attachment.  I still have
some trouble with the plate rotating properly but I hope to correct that
with a rubbing point that will nudge the plate a bit as it makes it's
stroke.

I tubed up the f5 pie plate last night and did some viewing with it.  It
is uncoated.  I was able to see the cloud bands on Jupiter and I split the
double star in the handle of the big dipper, though I am told that is no
great shakes to split.  I looked up the double star list at the Amateur
Astronomers site and I see two double stars in Casseopia.  If the weather
holds and I can get out there, I hope to look for those two and see if I
can split them.

David Davis
Toledo, OR 97391

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