From: "Thomas" 
To: "Ulhas Deshpande" 
Cc: "atm" 
Reply-To: "Thomas" 


Ulhas, sounds like your done, just one thing to keep in mind, when you dig
out the core there will be an edge effect, caused by the glass relaxing
after the preasure from the PoP is releaved.  This will present as a slight
turned down edge, I think. although I may be wrong I do know there will be
an effect....

Anyone want to weigh in here?

Clear skies, Thomas.
www.tjanstrom.com
www.norsewines.com.au
----- Original Message -----
From: "Ulhas Deshpande" 
To: "ATM" 
Sent: Friday, August 08, 2003 5:26 PM Subject: ATM My Cass'a'grin Project :
Mirror DONE


>
> Hello All
> Last night I sat down and compiled my last three days  KE readings. Three
> sets of four reading per Zone for six zones. I averaged ( meaned ?) the
> readings and then medianed. Entered these values in SixTests and the
result
> gave S=0.901 RMS 14.2 for Mean Values and S=0.865 and RMS = 16.7 for
Median
> values. Both SixTest files are below.
> Test Mean of 225 225R 225RR
> 203.0 60.0 Mirror, obstruction diameters (mm)
> Foucault
> 0.0 Source distance (0=moving source)
> y, mm X, mm
>    24.6  0
>    43.1  -0.60537
>    56.8  0.236008
>    71.6  -0.13335
>    84.1  0.735542
>    95.8  1.09855
> *
> 0.000 2504.870 Conic targets:  b, R (mm)
> 0.2065 Measurement std deviation, mm
> 2520.0 Longitudinal reading bias, mm
>
> Test Median of 225 225R 225RR
> 203.0 60.0 Mirror, obstruction diameters (mm)
> Foucault
> 0.0 Source distance (0=moving source)
> y, mm X, mm
>    24.6  0
>    43.1  -0.60537
>    56.8  0.0381
>    71.6  -0.13335
>    84.1  0.508
>    95.8  0.9906
> *
> 0.000 2520.000 Conic targets:  b, R (mm)
> 0.2065 Measurement std deviation, mm
> 2520.0 Longitudinal reading bias, mm
>
> Looking at the results I realised that most of the error was in the area
> below radius 30 which will be the central hole in the Cass Primary after
the
> core is removed. Using an obstruction of 60 in the setup the results
> improved dramatically to give S=0.942 for the median and S=0.940 for mean.
> It appears that the boundary between the core piece,which is fixed with
POP
> in the hole, and the main glass is either causing an error in the reading
or
> has prevented the core piece from conforming to the overall curve.
> So, since I have good value for the main portion of the mirror and I do
not
> want to take the risk of now spoiling the figure with further work, I
shall
> accept the mirror as finished and now think of Star Testing for
> confirmation.
> Cheers
> Ulhas
>
>

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