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[ATM] Hyperbola and TDE - Tenacious

Well, I have just completed my 22nd short figuring session followed by testing and I had been making progress reducing a TDE that came with my hyperbolic figure.  Was using Bob May's short half-stroke, and it's been working very nicely, thank you, Bob!  After session #21, my Strehl was 0.93 and my RMS error was 12.  However, it's hard for me to imagine that a mirror with even a little TDE could really have such nice specs.  So I would like to get rid of the TDE once and for all, as well as take out the central deep area.  (Sixtests data file is below.)  
 
After doing lots of the short half stroke the mirror got fairly zoney and the surface is fairly roughed up as seen through the tester.  I am tempted to try Tex's suggested TOT 1/4 W  stroke ( p.92, Fig. 42 ) to take down the high area and am wondering what anyone's thoughts on that are - too much risk for more TDE?
 
I suppose I could continue with the half-stroke, but it feels like I am asymptotically approaching my goal with it - i.e., it could take forever to completely eliminate the TDE this way.
 
 
Below is the Sixtests file after one little round of a center-deepening parabolizing stroke that seems to have taken me in the wrong direction a bit  (deepened the center and the TDE slightly,  and also reduced Strehl and raised RMS error).
 
Thanks for your thoughts...
Jay
 
-------------------------------------------------------------------------------
22nd Test Data Using Sixtests Analysis 1_21_05
202.4 0.0 Mirror, obstruction diameters (mm)
Foucault
0.0 Source distance (0=moving source)
y, mm X, mm
    18.263 2.7534
50.698 3.8926
74.790 4.2443
92.956 5.1943
*
-2.513 2605.542 Conic targets:  b, R (mm)
0.1500 Measurement std deviation, mm
2597.9 Longitudinal reading bias, mm
 
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