To: atm{at}shore.net
From: david.a.stevens{at}gm.com
Reply-To: david.a.stevens{at}gm.com


Hello ,

My continuing story of the 8" f/3.9 is as follows:

I am now using a 4.25" tool on my 8" mirror to parabolise and
using Tom Krajci posts  a while back ,I am progressing quite nicely. I am
still high in the center and edge but that classic shadow pattern is there
and i have a diffraction ring all the way around.  I have been here before
3 times and all three times that diffraction ring slowly fades away as I
get closer to full correction.

I guess my question is for all those of you who have experience with f/4
and lower mirrors. How can I prevent the edge diffraction ring from
dissapearing as I aproach full correction?? Having no diffraction ring on
the left side does indicate to me a turned edge, Right??

Any comments welcomed,

Dave

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