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(meteorobs) Re: [ASTRO] Dew prevention on lens with soap
In a message dated 98-11-06 13:54:26 EST, you write:
<<
Does the shampoo coating really delay dewing or does it actually just allow
the dew to condense in a uniform film that is less noticeable than the usual
small droplets?
Les Cowley<<
From what I've seen, it does both. When I first presented this thread on the
meteor observing mailing list, I related how I came about the idea in the
first place. As a fireman, I wear a breathing apparatus when I enter smoke
filled structures. When I breathed out into my mask, the condensation would
immediatly form on the faceplate. Needless to say I became essentially blind.
A long time ago, I use to rub a liquid soap dry onto the insides of the face
plate prior to a call. Condensation wouldn't even form on the faceplate during
the entire incident. I've tested it many times and I would breathe on it
heavily and notice no hint of condensation.
Now last night when I tested the soap on a piece of glass overnight, the
moisture eventually formed on the glass...but not in beads, but as a
continuous clear film. My guess the soap breaks down the electro static charge
or something like that with the end result that the water doesn't condense as
droplets of any visible size. I guess you can say the water got "wetter"? The
water on the glass looks like glass. Everything can be clearly seen thru it.
George Zay
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