ATM [Fwd: BOUNCE atm@shore.net: Non-member submission from ["Michael J. Coslo" <mjc5@email.psu.edu>]]

[Mel Bartels <mbartels@efn.org>]

owner-atm@shore.net wrote:

> From: "Michael J. Coslo" <mjc5@email.psu.edu>
> Subject: Mirror Polish Testing
>
>         I'm about 5 hours into polishing my 12.5 inch mirror. I'm
> using
> cerium oxide, W-B's brand of pitch, and micro-faceting the lap.
> Everything
> has proceeded beautifully so far.
>
>         I have been checking the mirror for degree of polish with a
> laser
> pointer, shining it into the mirror and observing how visible the beam
> is
> on the surface.
>
>         The beam is barely visible on most of the mirror, except for
> the
> last half-inch near the edge, the entire way round the mirror. There
> the
> beam starts to reflect a good deal more light. The polish of the edge
> looks
> fine under strong normal light.
>
>         Should I be able to proceed to testing the mirror now, or
> continue
> polishing?
>
>         Is the laser even a good method of checking polish?
>
>         thanx - mike -
>
>             mjc5@psu.edu