[meteorite-list] First attempt at photographing thin sections

From: Starsinthedirt at aol.com <Starsinthedirt_at_meteoritecentral.com>
Date: Tue, 5 Oct 2010 13:53:23 EDT
Message-ID: <3cf58.43199d9d.39dcc013_at_aol.com>

Hi Dave and list. I often work with circular polarizers as well as linier
polarizers. Not to mention full and 1/4 wave retardation filters.

Don't avoid the circular polarizers. When you invert them they function
as a linier polarizer. My main Xpol scope (An aus Jena Fluoval) has SunPack
Circular polarizers on it right now and they are a quality camera filter
that can be found (often quite cheep in odd sizes) on eBay.

For extreme extinction (black when full crossed transmitted light is
viewed) like what is needed for subtle changes in reflectance viewed in incident
light. I use a Glan/Thopson style mined calcite prism polarizer.

I use this technique on an aus Jena Neophot. The Gold Basin image set on
my micrograph gallery shows off this effect well. Please check it out.
The results are quite unlike any thing most people are accustomed to.

http://www.meteorite.com/meteorite-gallery/articles/gold_basin/

Any polarizers are useful. I have even used the filters striped out of
non functioning Sony PS3 disk readers. I wrote a Meteorite Times article on
that.

The film polarizers are a great start but they distort the image when used
in the analyzer position.

Tom



In a message dated 10/5/2010 11:29:31 A.M. Mountain Daylight Time,
dfpens01 at yahoo.com writes:
Nice job, Richard.

I understand that one should only use linear polarizers and that most
camera polarizers are circular. So, be careful with what you use.

Perhaps Tom Phillips can shed some light on the differences in polarizers.

Dave

--- On Tue, 10/5/10, Richard Kowalski <damoclid at yahoo.com> wrote:

> From: Richard Kowalski <damoclid at yahoo.com>
> Subject: [meteorite-list] First attempt at photographing thin sections
> To: "meteorite list" <meteorite-list at meteoritecentral.com>
> Date: Tuesday, October 5, 2010, 6:01 AM
> I had some free time tonight so I cut
> a few pieces of some plastic polarizing filter I had and
> used them on our biological microscope. I had picked up a
> few low priced thin sections at this past year's Tucson
> shows. For a first ever attempt at photographing thin
> sections in cross polarized light, I think I've done an ok.
> job.
>
> I've uploaded my first 5 to an album on Facebook. Below is
> a link that should be accessible even if you don't have a FB
> account.
>
> http://tinyurl.com/27uj6tk
>
> I haven't yet calibrated my field of view yet, so at the
> moment I can't offer the scale of the features in the
> images. Sorry.
>
> I'd appreciate any tips or advice the experts are willing
> offer to help make future images better.
>
> Thanks
>
> --
> Richard Kowalski
> Full Moon Photography
> IMCA #1081
>
>
>
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Received on Tue 05 Oct 2010 01:53:23 PM PDT