Re: ATM Foucault test accuracy

["Ken Hunter" <kb7h@onemain.com>]

And if you test with a pinstick using just a visable band across
the face of the mirror, (rectangular mask) there is less distraction
from the donut shading moving across the mirror! Match the
intensity at the pins and call it good.

Ken Hunter

----- Original Message -----
From: "Frank Ward" <thewards@mindspring.com>
To: "Steve Lindberg" <lindbergs1@home.com>
Cc: <ATM@Shore.net>
Sent: Tuesday, June 05, 2001 7:16 AM
Subject: Re: ATM Foucault test accuracy


>
> Steve,  You wrote >I like to judge the shadows when they just begin to
> darken in the Couder
>  windows<
>
> Interesting post, I use the blink method to judge the balance
> between two zones but (several mirrors I've made startested
> as overcorrected. You might have pointed me toward >my<
> systematic error. Anyone else out there want to comment on
> this?
>
> I remember a discussion awhile back when Nils Olaf and Jim
> Burrows were calling the center of the zone the most accurate
> point to hit. That's logical, but in practice the only way to do that
> accurately would be with a pinstick and I've switched to the
> mask because the pinstick left too much for me to "interpret" (read
> that "fudge") when I was anxious or tired.
>
>   Question proposed: Mirrors tested with the shadow "just appearing" might
> startest undercorrected and mirrors tested with the shadow filling
> the zone and blinking equally with each other might startest as
> overcorrected.
>
> Frank Ward
> Atlanta, GA
>  > Steve Lindberg, Olympia, WA
>  (original message deleted to help  keep Clive's finger where it is)
>
>
>