Re: new streetlight - comply w/ Dark Dky Initiatives

Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote in
news:dehfrb$f48$1@xxxxxxxxxxxxxxxxxxxx:

> They should be FCO shielded *and* LPS. Belgium manages to do it
> despite being vastly overlit. I am not saying that shielding is bad. I
> am just pointing out that numerically it also has its limitations.

Frankly, I don't think Belgium manages to do anything in that respect,
except of course lighting up everything. I live in semi-rural Belgium on
the edge of the Ardennes (in the yellow zone of Cinzano's map - that's the
best one gets)

http://www.datarescue.com/life/kepler/mysky.htm

One additional problem is that the skies are almost never truly blue. There
seems to be a constant whitish layer of haze in the sky (except maybe on
some very cold winter days) and that layer acts as a diffuser for the light
pollution.

Filtering does help to some extent, see the difference between a non
filtered and a filtered single shot here

http://www.datarescue.com/life/kepler/idaslpr.htm

but the jury is still out on whether it really goes deeper. Some French
amateur astronomers, and some well known ones, have expressed the opinion
that LPR filters were totally useless. I disagree - that was the reason for
the above comparative shot, but haven't been able to fully explore all
filter/exposure length combinations because of poor weather this summer.

Still, Martin, never ever mention Belgium as an example for anything about
light pollutions: it makes me want to cry ;-)
.