[ATM] Astigmatism need fixing? And how to do so?

[J Killea <jkillea@yahoo.com>]

Sheesh!  I thought I was done with this 8" f6.4, did some things to improve on some TDE, got to some nice readings on the radius I have been testing all along ("Axis 1" in the Sixtests files below) then I decided it was time to check the perpendicular radius.  Not reassuring.  Yep, probably should have checked sooner - out of sight, out of mind.
 
Along the better axis, I am at 21nm PV (surface), and along the other axis, PV= 45nm.  Also of concern is that along the poorer axis, b = -0.761, versus -0.941 on the better axis.  If I were an expert, I would probably dive in for one more time around the barrel to see if I could make things better; but several questions jump to mind (aside from the fear of setting myself way back):
 
1)  Do these measurements indicate significant astigmatism? ( I am not planning on using the scope for anything even as fancy as photography).  It would be a while before I could actually do a start test, since I don't have easy access to an 8" Newt currently  (OK, maybe a salamander).
 
2)  If I jump in there to try to help things out, any thoughts on things to do/avoid?  I would plan on a warm & cold press, then once around the barrel, to start with, of MOT parabolizing stroke with only light pressure on the center of the glass (thumbs only).  How would I deepen the center along Axis 2 without doing so along Axis 1?  Or is that not the way to think about this?
 
Thanks again for the ongoing support!  3 Sixtests files follow...
 
======================
Jay K.:  78th Test Sixtests Data File 2_11_05 Axis 1
202.4 0.0 Mirror, obstruction diameters (mm)
Foucault
0.0 Source distance (0=moving source)
y, mm X, mm
18.263 6.1271
50.698 6.7615
74.790 7.3565
86.512 7.5660
94.759 7.8562
*
0.000 2603.473 Conic targets:  b, R (mm)
0.1500 Measurement std deviation, mm
2597.9 Longitudinal reading bias, mm

==================================
 
Jay K:  78th Test Sixtests Data File 2_11_05 Axis 2
202.4 0.0 Mirror, obstruction diameters (mm)
Foucault
0.0 Source distance (0=moving source)
y, mm X, mm
18.263 6.5881
50.698 6.9412
74.790 7.3254
86.512 7.6416
94.759 7.8829
*
0.000 2603.473 Conic targets:  b, R (mm)
0.1500 Measurement std deviation, mm
2597.9 Longitudinal reading bias, mm

==================================
 
Jay K:  78th Test Sixtests Data File 2_11_05 Axes Averaged
202.4 0.0 Mirror, obstruction diameters (mm)
Foucault
0.0 Source distance (0=moving source)
y, mm X, mm
18.263 6.3576
50.698 6.8513
74.790 7.3409
86.512 7.6038
94.759 7.8696
*
0.000 2603.473 Conic targets:  b, R (mm)
0.1500 Measurement std deviation, mm
2597.9 Longitudinal reading bias, mm


		
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