From: "James Lerch" 
To: "ATM List" 
Reply-To: "James Lerch" 


> --- Jeff Baldwin  wrote:
> >
> > In a dark room with the mirror extremely well
> > cleaned, a hand laser works
> > well for finding pits.

If you happen to have a GREEN laser pointer, try pointing it in the edge of
the mirror aimed somewhat towards the surface.   BTW, this is one cruel
test.

Also, I recently read of another method of testing surface polish quality.
The test involves using an absorbent pad and acetone, which is gently
dragged across the surface.   Poor polish is reportedly indicated by an
increase in drag.  I keep meaning to try it, but alas I keep forgetting..
anyone else ever tried it?

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)

--- BBBS/NT v4.00 MP