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ocular dichroscope
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Author:  pezzottait [ Sun Oct 28, 2012 1:06 pm ]
Post subject:  ocular dichroscope

I am looking for an ocular dichroscope for a 30-mm-slot.
Does somebody know a source for it, please?

Regards from Styria, Austria

pezzottait

Author:  G4Lab [ Tue Oct 30, 2012 9:51 am ]
Post subject:  Re: ocular dichroscope

You will have to have this custom made Or make it yourself.
If you send me a private message I may be able to assist.
These are not in anyone's catalog. There were a short handful of them made with calcite one hundred years ago and with polaroid after WWII. But those were pretty much custom made as well.

Author:  Barbra Voltaire, FGG [ Sat Nov 03, 2012 11:10 am ]
Post subject:  Re: ocular dichroscope

Pezzottait is a new member and can not PM you.
If you can assist with this question, I would request you do it publicly.
Thanks.

Author:  G4Lab [ Sat Nov 03, 2012 2:27 pm ]
Post subject:  Re: ocular dichroscope

You can make an ocular dichroscope by obtaining an ocular which fits your microscope that is intended to receive a reticle or graticule. You then cut two circles of polaroid material in the diameter of the reticle required for your ocular.

You then cross the polarizers and cut them in half so that each half circle is oriented at right angles to one another. You then place these in position where the reticle would go.

There are different ways that different microscopes companies have for holding reticles.
The polaroid does not need to be glued if it is held in place firmly. Furthermore you can also do a variant where you cut the two circles into quarters and use two quarters of each orientation in a checkerboard pattern. Or you can slice them into bands and alternate them.

It may be necessary to mount them between glass using optical contact cement.
If that appears necessary I will post instructions on how to do that.

http://www.minersoc.org/pages/Archive-M ... 09-163.pdf

The article describes how to make one. It makes reference to how difficult it is to cut polaroid film without damaging it which is still true. The best method I have found is to gently compress it between to microscope slides and use a brand new single edge razor.

Some microscopes are likely to have difficulties with this technique. They may either add polarization causing erroneous colors to appear, or distort the dichroism of the specimen under observation. This is why when petrological compound scopes are made there is additional procedures and testing done compared with otherwise identical optics. They then have the label Pol engraved on them. This also applies to other parts of the scopes. But often it does not matter. I have put polarizers on all kinds of scopes (but not dichroscopes) and not usually seen a problem. The same is likely to be true for using a dichroscope.

Author:  pezzottait [ Sun Nov 11, 2012 9:43 am ]
Post subject:  Re: ocular dichroscope

@G4Lab
Many thanks for your link and the literature.

Regards from Austria
pezzottait

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