From: "Stathis Kafalis" 
To: "ATM" 
Reply-To: "Stathis Kafalis" 


I do the testing of the polish with a flashlight and a strong magnifier
(eyepiece). See here at polishing:.
http://www.geocities.com/dobsonstathis/32inch_mirroreng.htm

The advantage is, that you directly can see the pits, whereas a very dull
laser reflex in the dark can even be seen on a completely polished surface.
I do the laser reflex test in addition to this, to compare the edge with
the rest of the mirror. Only if the reflex at the edge is as dull as at the
rest, it is polished out.

Stathis Kafalis
http://www.geocities.com/dobsonstathis

----- Original Message -----
From: "Steve Fejes" 
To: 
Sent: Sunday, February 02, 2003 2:25 PM Subject: ATM polished surface quality


>
> What is meant by 60/40 scratch/dig surface quality?  Are these scratches
> and digs counted per square millimeter or centimeter?  Should I use a
> microscope with oblique lighting to view these surface defects?
>
> I want to determine the surface quality of a telescope mirror to know
> when it is polished enough to start figuring.
>
> Thanks,  Steve
>
>

--- BBBS/NT v4.00 MP