From: "Mel Bartels" 
To: 
Reply-To: "Mel Bartels" 


>>> The link below shows a current pic of the ronchi test on my mirror.

You basically have a spherical mirror with broad rolled edge.  Don't worry
about the center - so much of it has to be removed via standard
parabolization techniques that the fact that it is slightly *high* is
immaterial.

Viewing from the perspective of the 70% zone, the edge and the center are
focusing long (the bands are closer together at center and edge).  That
means rolled edge and high center.

There is astigmatism in the image as denoted by unequal twisting of the
Ronchi bands - could be due to a number of factors including light source
to viewing position spacing and mirror mounting.  You might want to rotate
the mirror 60 degrees and carefully compare images to verify that the 'stig
does not reside in the glass as a permanent feature.

Mel Bartels

--- BBBS/NT v4.00 MP