[ATM] Re: Satisfying "Mililes-Lacroix" is neithernecessarynorsufficient for "diffaction-limited" performance

["Koehler, Steve" <Steve_Koehler@securecomputing.com>]

I meant to send this to the group...

-- Steve Koehler
   steve_koehler@securecomputing.com

-----Original Message-----
From: Koehler, Steve 
Sent: Tuesday, June 22, 2004 10:13 AM
To: 'Nils Olof Carlin'
Subject: RE: [ATM] Re: Satisfying "Mililes-Lacroix" is neither
necessarynorsufficient for "diffaction-limited" performance

Nils Olof,

I put my last diagram (rms_rta2.png) in 

    http://www.visi.com/~mkoehler/rms_rta/rms_rta2.png

This shows simulated star tests for extremes of RTA values out of a
collection of simulated mirror surfaces.  The intent here was to show that in
the presence of turbulence, high RTA surfaces show worse spikes in the star
test than low RTA surfaces.  

Please let me know if you think any of the other diagrams would be useful for
this discussion.

-- Steve Koehler
   steve_koehler@securecomputing.com

> On another list have been shown some nice simulations of diffraction
> images
> for identical RMS errors but widely different transverse aberrations(RTA).
> My simplified view is that the RMS says how much of the light is within
> the
> Airy disk and how much in the rings, but the RTA says something about how
> wide the light is scattered in the rings. A small amount that is widely
> scattered may be objectionable in much the same sense that the spikes from
> the spider vanes are. One other consequence is that turbulence seems to
> affect a high RTA mirror by increasing the "spikiness".


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