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Re: (meteorobs)Dew prevention on lens with soap


GeoZay>noticeable with a wide open f/stop. If there is concern about
destruction
to a
>lens coating, perhaps one can coat the outside of a UV filter instead of
the
>lens? I'd prepare for this during the day or another day by attaching the

    Ed>>Fast meteors such as the Perseids have strong emissions at the blue
end
of the spectrum, ie.  H & K lines of Ca+.  UV filters may prevent you from
recording this region and thus reduce your chances of recording the fainter
meteors of this type.<<

For a long while I use to shoot meteors with a UV filter...got plenty of them
with it on. Later took it off and still get about the same magnitude threshold
when everything else is taken into consideration. There appears to me to be no
appreciable noticeable effect having a UV filter on or not when photographing
a meteor? I understand that the glass that makes up the lens of a camera will
filter out a certain amount of UV light as well? a little more filtering
probably wouldn't hurt?

  Ed>>  I would be careful using liquids on the lens, as the film may
introduce
distortions.  <<

Slight  distortions is a possibility, but it would be not half as bad as the
totally fogged over lens where you have no chance to get anything...not even
stars. I've been that route...sure wished I thought about using soap then. 

Ed>>When I was in the military we coated the inside of our gas
mask lenses so they would'nt fog up; you could see, but the view was
degraded to some extent.<<

The soap coatings I use on my BA masks aren't noticeable at all. 

There is another product that we sometimes have...and I know can be found in
fire fighting product catalogs if you hunt for it, that are designed to be
coated into the face masks for fog prevention. These would be a step up on the
use of soap for the same thing. I remember as a rookie that I got my hands on
several tubes of a paste designed to be used on the shields of astronaut
helmets. we used them inside our masks.  Perhaps a similar product is
available?  
George Zay
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