Keep Polishing! Don't give up!
>
>I took four zone readings, and went upstairs to fight it out with
>the Texereau book.
>About 90 minutes later, I had computed the billion values in his
>spreadsheet like form, and the result is...
>
>The maximum deviation from a parabola is 1/16 wave.
>
>Now, I really don't believe that I just lucked onto getting such a good
>parabola the first time without even trying, so I expect that I dropped
>an order of magnitude here and there, and I have a One-wave mirror or so.
>(An 8 Inch f/7 mirror that is spherical is a One-wave mirror)
I've seen beginners hit a very high quality parabola on their first try.
It does happen.
>
>I'll take several reading, and rotate the mirror 90 degrees, and take
>several more like Texereau suggests, and then compute all over again
>and then I'll get back to you all.
While Texereau's math is tedious, it is impeccable. You might try using the
Milles-LeCroix method because it is very fast and accurate, and then verify
with Texereau.
>
SteveS
-- Steve Strickland Lensnut@tpoint.net