27 replies to this topic

[csa/montana]

Last warning, about taking posts here as personal, and discussing it here.  

 

Next warning, will include a lock.

[ddouble518]

I feel your pain. I was in NYC when they switched to the unshielded 4500k cobra LED’s our street looked like a prison yard. Fast forward 10 years later, I noticed out town switched a dead HPS light with a similar design. I had a productive conversation the the commissioner of public works, brought the data concerning blue light effects on nocturnal habitat etc… fast forward 3 years and all new lights are shielded 2400-2800k led lights. They actually give off LESS sky glow than the old HPS lights.

[yuzameh]

Those lights are inherently filtered, they are directly downward pointed and recessed in their casing LEDs, which is the point of their design.  You'll notice that the transparent cover is flush with the rest of the housing.  We have 'em here now, and they certainly aren't the original LED streetlight headmounts we orignally had, and I didn't even notice we'd had them fitted until one night I noticed the white sky haziness or rather the crispness of the sky background has gotten better of late.  That is, yeah, they ain't great, but they're better than the original LED light fitments were by a long way, whilst still being far worse than low pressure sodium (we had mercury bulbs for major roads and high pressure sodium for urban streets for a while before that and they were just as bad in their own way).

 

However, the road and pavement/causeway/footpath (you might need an English to USofAian dictionary translator), especially if tarmac/ashphalt surfaced and very especially if damp after rain or such, is not filtered and has roughly the albedo of the Lunar Maria, and you know how bright they are on a full Moon.  There's absolutely nothing you can do about that except lobby for reintroduction of low pressure sodium streetlighting, which will not occur, not because of environmentalism, but because of the limited budget for covering the every increasing electricity usage costs of streetlighting that modern municiplaties are subjected to.  It is budgetting and usage costs that dictate their deployment, not any environmental programme.

 

I remember when xmas municipal xmas lighting was a seasonal set of red, green, yellow and orange lights, and not white LEDs and most especially not weird electric blue coloured ones, but I'm not going to be able to do anything about that nor are you going to get anywhere (anyway, our town's xmas lighting has been abysmally anaemic and bland for years, even before they nearly went bankrupt).  But mostly you won't get anywhere because environmentally designed and cost effective lighting taking into account lack of direct upward light pollution has already been fitted.  The fact that it doesn't work because of ground surface reflection and because of the broad spectrum output and that the frequency bias at the blue end is ideal for being scattered by atmospheric aerosols, whether the latter are natural or not, is just our massive bad luck.  And that's the polite version.