Re: Koehler illumination in conoscopic observation


"Andy Resnick" <andy.resnick@xxxxxxxxxxx> wrote in message
news:fikjc9$i3$1@xxxxxxxxxxxxxxxxxxxxxx
Kevin Cunningham wrote:
<snip>


A ground glass filter should be used, I'll bet there is a place for
one. Other wise I'd put it close to the lamp, if possible directly in
front of the lamp. Then, technically, your using critical
illumination, not Kohler but who cares?

I don't think that's correct- critical illumination is the Fourier
transform of Kohler illumination: the filament is focused onto the
sample plane rather than the entrance pupil of the condenser. And
actually- that's the better solution.

Using a ground glass plate is a kludge to destroy the image of the
filament in the back aperture of the objective lens; it may work, but it
isn't critical illumination.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University

Hello Andrew,

Thanks for your clarification. It would be interesting to try critical
illumination. Unfortunately I can't think of a way to place the light
source or its image into the plane of the field diaphragm on my
Nikon scope. Should there be a way I would be happy to try it.
Please let me know.

G.R.


.

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