OK, Todd! Where were you when I was getting beat up on the list a month or so
ago on this
topic? ;^)
I never cease to be amazed at the wide range of expertise, beyond Roadsters,
that I
encounter among list members.
Gary McCormick
San Jose, CA
Todd Osborn wrote:
> Gary,
> I think the confusion here comes from the use of yellow tinted sunglasses to
> cut glare in hazy conditions. These sunglasses increase contrast by
> filtering out blue light; haze is very small (about 1 micron) water droplets
> and dust particles, which preferentially scatter short wave length (violet &
> blue) light. The scattering intensity of the much larger (greater than 10
> microns) Fog droplets is practically the same for all wavelengths, so yellow
> light scatters just as much as white. Incidentially haze causes mostly
> forward scattering (same direction as illumination source), while fog and
> clouds cause mostly back scattering. This explains why the sky is so bright
> on a hazy day and why the under side of cloud are so dark. For more info
> look up Rayleigh and Mie scattering
> http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html
> Todd Osborn
> B.S. Meteorology (class of '81)
>
> ----- Original Message -----
> From: "Gary McCormick" <svgkm@halley.ca.essd.northgrum.com>
> To: "Datsun Roadster List" <datsun-roadsters@autox.team.net>
> Sent: Wednesday, February 28, 2001 7:29 AM
> Subject: Fog Lights
>
> > This may not be the last word on the issue, but FWIW, here's what I heard
> back from the
> > technical folks at Road & Track magazine on the subject of yellow vs.
> white fog lamps:
> >
> > RTLetters wrote:
> >
> > > Gary,
> > >
> > > I talked to Dennis Simanaitis, our engineering editor, and he agrees
> with
> > > you that there has not been proven any advantage to using yellow lights
> in
> > > foggy conditions. Like you said, the only reason they seem like they
> give
> > > off less glare is because they are usually of a lower intensity, so the
> > > reflection is less.
> > >
> > > Hope this helps,
> > >
> > > R&T
> > >
> >
> > Gary McCormick
> > San Jose, CA
> > '70 2000 (doesn't have fog lamps, doesn't need 'em - doesn't run... )
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