Re: Bohren on sunsets

[brian whatcott <inet@INTELLISYS.NET>]

It is always pleasing to see some modest, unassuming appeal
 to experiment like Craig's in resolving a conceptual difficulty.

Not quite on topic, but close, a simple sky photometer shows
surprising long period fluctuations of sky light intensity
at the zenith with frequencies below 0.2 Hz
 Wonder what a spectrum would look like?
   This would be a rather easy and quick experiment to replicate.

Brian

At 15:53 8/31/00 -0700, Dan wrote:
...
> I finally asked Craig Bohren himself to help ...

> > >  ... what is the relative importance of small particulates
> > > vs. clean air in the scattering process? ...
> > > Dan Schroeder
> >
> > Hi Dan,
> >
> > You asked the right man about this.
> > ... we tried our best to demolish all the crap about sky colors. For what
> > it is worth, I have never in my life seen an explanation of the blue sky
> > and red sunsets that wasn't either misleading, partly wrong, or hopelessly
> > wrong.
> > ... particles are needed to give red sunsets. By red I mean
> > colorimetrically red, not orange or yellow....

> > To fully understand sky colors requires some knowledge of multiple
> > scattering, about which most physicists learn nothing.
...
> > Craig
brian whatcott <inet@intellisys.net>  Altus OK
                Eureka!