From: "mlbrown{at}everstrive.com" 
To: atm{at}shore.net
Reply-To: "mlbrown{at}everstrive.com" 



Gouges are old scratches slowly polishing out.  My lap press is a plank
with a pile of books on it.  My cat decided to try it out as a perch.  Not
quite sure what exactly caused the scratch, but it was there when I pulled
the mirror out of the pile.  It is visible to the naked eye.  The cat is
now traumatized, and keeps far away from the ATM worktable.  I'm not
concerned about the scratches.  These Things Happen, and it won't affect
the image enough to worry about.

=Matt

Original Message:
-----------------
From: Dave McCarter dmccarter{at}sympatico.ca
Date: Thu, 3 Apr 2003 13:00:28 -0500
To: mlbrown{at}everstrive.com
Subject: Re: ATM Am I done yet?


Why the gouges at noon and 8 and the pock mark below noon nearer the
center? Yes the center is gently high, and could be taken down in a jiffy,
so be careful to not overdo it. The surface otherwise looks quite smooth.

Dave
----- Original Message -----
From: "Matthew L. Brown" 
To: 
Sent: Thursday, April 03, 2003 12:18 AM Subject: ATM Am I done yet?


>
> Mirror: 4.25" f 9.2
>
> The readings now look decent, though I think the center could be lower.
> What I'm worried about is the roughness.  It looks worse to my naked eye,
> though there are more than the usual air currents in my testing room.
>
> Foucault Image (45kB JPEG)
> http://host67.everstrive.com/~mlbrown/ASTRONOMY/KnifeEdge2Apr.jpg
>
> Sixtests says Strehl 0.996 rms 2.7
>
> Tex says 1/19 lambda
>
> Readings (inches)
> zone 1 2 3
> 0.041 0.037 0.067
> 0.035 0.040 0.066
> 0.036 0.045 0.066
> 0.030 0.043 0.067
>
>
> TEXEREAU MIRROR TEST SHEET
>
>             Comments:    Optical diameter: 4.15
>    Readings per zone: 4
> Radius of curvature: 76.62
>                  f/D:  9.23
>     Diffraction disc: 0.000243264
>
>   1 ZONE                1          2          3
>   2 h(x)              1.1980     1.6940     2.0750
>   3 h(m)              0.5990     1.4460     1.8845
>   4 hm**2/R           0.0047     0.0273     0.0464
>   5 hm/4f             0.0039     0.0094     0.0123
>   6 D1                0.0355     0.0412     0.0665
>   7 D2                0.0355     0.0412     0.0665
>   8 D12               0.0355     0.0412     0.0665
>   9 D12 -  0.0189     0.0166     0.0224     0.0476
> 10 Lamda c           0.0119    -0.0049     0.0013
> 11 Lamda f * 1e5       4.66      -4.66       1.54
> 12 Lamda f / rho      0.192     -0.191      0.063
> 13 u * 1E6            -1.22       1.22      -0.40
> 14 Wavefront          -1.12      -0.18       0.00
> Reference parabola: y = -0.233909 * x**2 + 0
> passing through (  0.00,  0.00) and (  2.08,  0.00)
>
> Maximum wavefront error = 1 / 19.3 wave at zone 1
>
> Results for individual sets of readings:
> Reading set 1: 1 / 12.5 lamda, Max Trans Abberation=0.30
> Reading set 2: 1 / 18.8 lamda, Max Trans Abberation=0.20
> Reading set 3: 1 / 21.0 lamda, Max Trans Abberation=0.15
> Reading set 4: 1 / 36.8 lamda, Max Trans Abberation=0.11
>
>
> Do I quit while I'm ahead or try to simultaneously drop the center and
> smooth it out a bit?
> Thanks for the advice.
>
> =Matt
>
>
>
>
>



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