[Leica] astronomy anti-light pollution question

[abridge at gmail.com (Adam Bridge)]

There's a pretty good "dark sky" movement active in the US and Canada
and probably Europe as well. We've been gradually changing to dark-sky
lighting here in Davis where all new lighting is required to be
compliant and old lighting is retrofitted as it is replaced. It
definitely makes a difference! For a while UC Davis had two parking
lots adjacent to each other along I-80, one dark-sky and the other
conventional. The difference was astounding. There was still as much
light reaching the ground but it wasn't coming out to the sides. I
have to think it was more efficient as well.

So I'd suggest that he talk to what-ever agency owns the light and
have a word with them about re-directing the light downward.

In the area around the Palomar observatory they only use sodium
discharge lamps - the reason being that these lamps emit on a very
narrow range of frequencies and it's possible to filter the
back-scattered sky-light out. Normally I really dislike these lights
but now that I understand I'm much less averse to them than I used to
be!

ab