Re: [ATM] Report from a professional optical shop near Baltimore

[Dominic-Luc Webb <dlwebb@canit.se>]

> We also saw how they got a rough polish on one of
> their mirrors (of about 36 inch diameter): they made a
> metal tool to fit its curvature, then glued a pad and
> then some nylon loop carpet to the tool!

This part of your story was particularly interesting to me because
I have had a real nightmare polishing my very fast mirrors (F1.0
to F/1.5). There is a natural tendency for pitch, etc to rub off
disproportionately on the edges. The thicker the pitch lap, the
worse this problem gets. The signs are clear. The center gets shiny,
the edge does not. My tools thus far are concrete, but for this last
stage, I think I will prefer some kind of change in the future. I
actually tried thin pieces of carpet and other fabric-like materials
on the tool and this thus far has done a lot better job of keeping
the two surfaces in even contact. I have been thinking in terms of
flexed (adjustable) metal reminiscent of Alan Adler's flexed mirrors.
It seemed quite efficient to immediately adjust the tool to compensate
for polishing that is clearly not going the right way. At the moment,
I have a few different tools I can quickly swap between and this has
proven to be a real blessing.

I am nonetheless overdue for a visit to one of these pro shops
you have been so fortunate to visit. I would not mind seeing some
pictures of such a shop sometime.

Dominic-Luc Webb

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