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Re: Re: [ATM] Re: Hyperbola and TDE - Tenacious
Jim Burrows posted:
======================
Sixtests on file #25 says that the half stroke was powerful - you
overshot
the parabola by quite a ways - RMS up to 44.7 nm, conic constant b is
now
-.577, undercorrected. Try the following to get to my suggestion:
1) click "Target"
2) click b window, put -1 in the dialog box, OK (why did you put the
-2.513
in the input file? - handier would be to put -1 0)
3) uncheck R-fixed
4) click R window, then hit down arrow once (get fixed R = 2603.738)
Relative to this parabola, the center is very high, and makes the TDE
look
less threatening. Then Tex says, p. 97, for "Center too flat, turned
down
edge" do "Method A, stroke II", "Method B, stroke II", or "Method C,
stroke I".
Try one of these, but short spells to see what works,
==============================================
Jim, here is part of my post on a Mike Lockwood question. (Please note: This is a couple of figuring sessions since my last post - I have completed session and test number 27, while that last post was after session 25.) :
"I am currently thinking of continuing to reduce the TDE using this TOT W method [ i.e. short TOT W with lap edge just over the zone 3/4 boundary (my mask has 4 zones total). According to Sixtests, when I use a sphere as my target conic ( b = 0.0 ) I am quite close to that shape except for that TDE. My "b" is -0.385 presently, so maybe if I just go for a sphere I will be able to safely parabolize without a lot of other figure issues getting in the way. Granted, my radius will be a couple millimeters longer than ideal, but I would be happy to have a good f/6.4 mirror!"
Essentially, I am applying your suggestion to parabolize, but first I want to work on that TDE just a bit more. Interestingly, Sixtests indicates I should press down at the zone 3/4 boundary to eliminate TDE relative to sphere, but eliminating TDE relative to parabola would require me to press down at the mid-zone 4 area. The different between those two locations is less than 1/4 inch. I hope I can be that precise, and still be random. Either way, this should move me in the right direction.
Below is the Sixtests file: Thanks!
%%%%%%%%%%%%%%%%%%%%%%
27th Test Data Using Sixtests Analysis 1_25_05
202.4 0.0 Mirror, obstruction diameters (mm)
Foucault
0.0 Source distance (0=moving source)
y, mm X, mm
18.263 5.6134
50.698 5.6020
74.790 5.1511
92.956 6.2281
*
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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