From: "Jerry" 
To: "'scottythefiddler'" ,
        "'Jerry B. Hillman'" ,
        
Reply-To: "Jerry" 





First, let me kiss the ground you walk on, because you have 'licked' the
TDE.   The large gentle curve that you see in the outer area is a shorter
ROC than in the central area where the bands are straighter.  i.e. a large
turned up area!

I think you are mixing up the inside and outside ROC Ronchigrams.

There is a turning down outer zone. But it doesn't roll off as much as the
desired correction for the parabola. If the correction across that outer
zone continued across the flat, actually very slightly oblate central area
to the center it would be well toward the parabola but still
undercorrected. I would not call the edge turned down except to say that
almost all edges turn down in the last 1/10 inch and this one isn't
exceptionally turned. I would not reject the mirror because of that edge if
it had a good parabola unless I was prepared to work hard and perhaps not
really get the edge much better.


Jerry

--- BBBS/NT v4.00 MP