[ATM] A pie plate scope, some pictures

[vorblesnak@peak.org]

Here are some pictures of the pie plate scope ...

http://www.atmlist.net/contrib/vorblesnak-at-peak-dot-org/Pie%20Plate%20Scope/

I have not had much time to work on any ATM projects, but I want to get
the ultrathin stuff working and coated. I made this scope to star test the
pie plate as it comes into figure.

I made the scope out of salvaged wood.  It is all plywood.  The OTA with
mirror installed weighs in at 8 pounds.  The base is close to that.  Once
I get the star testing done I will clean it up and paint it.

The pie plate mirror shows a slight astigmatism, the center is not quite
corrected.  I suspect both will be cured at the same time.

I am figuring on a star type lap with the plate full of water.  This pulls
the heat of the polishing off and helps to prevent distortion.  It also
slows my stroke significantly, which should help with the turned edge.

After a polishing session the curve looks good and there is no
astigmatism.  But after cooling for a while the center flattens off and
the astigmatism returns.  I suspect this is due in part to the emblem that
is stamped into the middle of the plate during manufacture.

David Davis
Toledo, OR 97391

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