Re: [ATM] Which stroke ?

[Jim Burrows <burrjaw@earthlink.net>]

At 2004-05-04 20:35 +0200, Eric Royer wrote:

>So I'm going to try what Bob suggests (short strokes to remove the hole). But
>I'd like a clarification about the edge. Jim says there is some TUE and Bob
>says there's some TDE. Does this depend on the way to interpret the other
>parts of the mirror ?
>In other words saying "central hole, with TDE assuming the intermediate zones
>are correct" is equivalent to "center is correct, a hill in zones
>2 and 3 and a TUE" ?

Essentially, it's "equivalent" relative to different parabolas.  If you run 
this input file into Sixtests:
------------------------------
Eric
203.0   0.0     Mirror, obstruction diameters (mm)
Foucault
2520.0  Source distance (0=moving source)
y, mm   X, mm
      28.37     1.82
      56.36     3.44
      72.17     4.34
      85.11     4.86
      96.32     5.28
*
-1.000  2521.010        Conic targets:  b, R (mm)
0.0100  Measurement std deviation, mm
2520.0  Longitudinal reading bias, mm
---------------------------------
Relative to the optical best-fit parabola (R=2521.0 mm), the plot shows, 
probably like TEX, low center, 12 nm hill @ 50% zone, and TUE.  Now click 
"Target", then the R window, and hit the down-arrow twice.  Vs. the 
parabola w/R = 2520.8, the plot shows high center and TDE.

It's generally easier to push this surface toward that parabola, which 
suggests Texereau's parabolizing stoke A II on p. 97, that deepens the 
center.  Really short spells between testing - it's easier to mess up 
rather than improving things when you're so close.

         -- Jim Burrows
         -- mailto://burrjaw@earthlink.net
         -- http://home.earthlink.net/~burrjaw
         -- Seattle N47.4723 W122.3662 (WGS84)  

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