[ATM] Phase Contrast and Foucault image puzzle

[Dale Eason]

Herbert Highstone told me and showed me how.  Slide a
glass plate over a candle about 5 times with the glass
about 10 to 15 mm over the wick. Make the strip at
least 25mm long.  Next make straight sides on the soot
strip by scraping with a sharp flat stick guided by a
straight edge.  Soot strip can be fairly wide.  Mine
are about 5mm or larger.  Use one side of it like a
knife edge.  Try various densities until you get it
right.  Sharp cuttof of the side of the strip is
important thus the scraping.

Glass plate was about 50mm on each side.  I started
with microscope slides held horizontally and masked
the top and bottom so the camera could not see around
the slide.

You need a large camera lens 50mm in diameter and a
very bright slit source. Light source was a slide
projector.  Slit was home made.  Slit should be about
50 microns wide and 5 mm in length.  

I used my Nikon D40 with a 135mm F2.8 35mm film camera
lens.  Exposure was about 1/10 sec. 
 
Dale Eason


--- Vladimir Galogaza <vladimir.galogaza1 at zg.t-com.hr>
wrote:

> Dale,
> 
> Have you made phase plate by yourself?
> If yes, how you did it?
> 
> Regards
> Vladimir.
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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