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From: Alexandre Eremenko (no email)
Date: Thu Oct 14 2004 - 13:36:40 EDT
Herbert:
On Thu, 14 Oct 2004, Herbert Prinz wrote:
> How do your visors work? Can you clamp them on?
They are L-shaped pieces of aluminium, about 1 inch high,
1/2 inch wide with sharp upper edge.
They cannot be clamped. You just put them on the arc.
Using these visors, it is hard to keep your eye precisely
on the height of the visors upper edges. So I think the
cylinders would be better (their flat tops would help in control
your eye position).
That's why I proposed a modified version of the test using these visors:
they should be installed on unequal distance from the axis,
to compensate the excentricity of the mirror.
This distance is easy to find experimentally, in my case it is
about 5 mm.
And the criterion that they are installed correctly is this:
the alignment that you see during the test does not depend on your
eye position:-)
There is only one position of the visors with this property.
(Assuming their centers near 0d and 120d and the index is installed
on 35 d).
Alex.
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