Light Pollution Getting Worse

CroMAGnet

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lightwater

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I was in central Australia a few years back. It's amazing just how clear the skies were from all sorts of pollution. I don't think you could stuff another star in the sky. Hopefully one day we can clear up the pollution from our "civilised" societies. There would be better health all round, clean air to breath, see the sky!
 

fyrstormer

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Light pollution isn't getting worse. There are all sorts of new standards for outdoor lighting fixtures that don't allow stray light to escape upwards. If anything is getting worse, it's suburban sprawl, which means there are more outdoor lights total, regardless of how good they are at containing stray light. Also a problem is the sulfur content of the air, which makes it more reflective and dims the incoming starlight regardless of any light pollution.
 

VegasF6

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The story mentions Chicago as being the worst offender. I can't imagine anywhere being worse than Las Vegas on this issue.
 

SemiMan

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Dark sky compliant lights are a nice concept, but they don't prevent light from reflecting upwards!

The issue is not so much the type of lights we use, but just how much of them and how bright they are.

The IES enhanced security level for parking lots is 5 lux minimum. Most retail lots are 4 or more times that. Dealerships are 100 times that which may be okay when they are open, but the lights are left at that level all night!

Semiman
 

cerian

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A building closed to where i live installed a LED display matrix, it literally light up half of the night sky and it is not comfortable to look at. I hope the light intensity is going to down a bit as it age.
 

LEDAdd1ct

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Dark Sky Finder

I think one of the reasons I like camping is the dark and the quiet.

The noise of my hard drive motor, a pigeon cooing, the refrigerator motor, birds, heating pipes...

Being somewhere completely quiet and completely dark is disconcerting at first and then incredibly,
soul-stirringly rewarding.
 
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Anders Hoveland

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Ironically, the switch to LED streetlighting could make light pollution even worse. The yellow-orange frequency in the sodium line diffuses in the atmosphere less than the higher frequencies from LED. Then there is the color contrast, it is easier to see stars against the orange polluted background than a bluish white polluted background.
 

jtr1962

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Ironically, the switch to LED streetlighting could make light pollution even worse. The yellow-orange frequency in the sodium line diffuses in the atmosphere less than the higher frequencies from LED. Then there is the color contrast, it is easier to see stars against the orange polluted background than a bluish white polluted background.
LEDs might help more than hurt because nearly 100% of the light can be directed exactly where you want it. HPS/LPS lights direct a fair percentage of their output upwards. When it snows or is foggy, I noticed the sky has a hazy orange glow. Also, due to the higher blue content, the apparent brightness of LEDs at any given lux level is higher. Therefore, you can reduce lighting levels without sacrificing perceived output. That should also help. The point here is we really don't know how LED will affect the light pollution situation until a large city has mostly LED streetlights.
 

SemiMan

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LEDs might help more than hurt because nearly 100% of the light can be directed exactly where you want it. HPS/LPS lights direct a fair percentage of their output upwards. When it snows or is foggy, I noticed the sky has a hazy orange glow. Also, due to the higher blue content, the apparent brightness of LEDs at any given lux level is higher. Therefore, you can reduce lighting levels without sacrificing perceived output. That should also help. The point here is we really don't know how LED will affect the light pollution situation until a large city has mostly LED streetlights.


There is nothing inherent in LPS/HPS that the light has to go upwards. Many progressive areas have been installing full cutoff HPS fixtures for some time and I am finding more and more cities, towns, etc. are insisting on at least semi-cutoff if not full cutoff fixtures for all installations no matter the technology. I have not seen movement to the more modern BUG standard yet, but it should come.

Apparent brightness does not impact used lighting levels at all though. Apparent brightness and real world impact do not always coincide.

For roadway lighting due to the speed of movement, the central cone of vision is the most important, hence photopic or at a bare minimum mesopic levels are used. For slow speed residential roads you may be able to reduce lighting levels 25%(more?), with the advantage diminishing as the speed goes down.

Where you could get the most benefit is parking lots, but I find that more newer parking lots are being lit with blue rich metal halide already and would see now advantage (spectrally) going with LEDs. What they could do though is not make them so bloody bright!

Completely agree with placement accuracy of LEDs having the ability to reduce light pollution. It is not unusual to be able to hit the required lighting levels on a road with 30-50% less lumens than an HPS (measured at end of life in both cases). LED lighting is also far more amenable to electronics controls. Turning down streetlights at night does not impact safety as the traffic levels are less and hence not as much light is needed.

As LED efficiency improves, I think you will see a move towards 4000k(ish) as the standard for outdoor LED lighting. 5000K+ is not really justifiable. It does not enhance vision appreciably but contributes to added glare.

Semiman
 

TEEJ

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I was born in NYC. I had been MOSTLY in/near cities my entire life.

BUT - When out west, a great joy was laying on my back in the desert...looking up at the night sky, like a velvet dome, covering from horizon to horizon. The dome was dotted with stars, millions and millions of them, stars I had never seen before, and which added a depth and breadth to the universe as I knew it. I was maybe 10 years old, but, I still remember it with awe.

It also made me realize what I'm missing back in civilization; the universe.
 

Cataract

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Believe it or not, many cities have "laws" that should contribute to reduced light pollution. The issue is lack of adherence and enforcement.

Semiman

Mostly lack of enforcment IMO. This one city has done it and many people finally realise it is not necessary to have super bright lights to see where they're going. I can't find the news article anymore, but the before and after pictures showed a very obvious difference.
 

SemiMan

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Mostly lack of enforcment IMO. This one city has done it and many people finally realise it is not necessary to have super bright lights to see where they're going. I can't find the news article anymore, but the before and after pictures showed a very obvious difference.

Every day I see new installations around me that I know for a fact do not meet the cities planning guidelines.
 

Cataract

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Every day I see new installations around me that I know for a fact do not meet the cities planning guidelines.

Yup, and so it is in many many fields. I see things that make me shiver every week and those people are audited by very strict companies. There is still hope on the horizon, but the horizon is not at the same distance for everyone...
 

TEEJ

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Yup, and so it is in many many fields. I see things that make me shiver every week and those people are audited by very strict companies. There is still hope on the horizon, but the horizon is not at the same distance for everyone...

Hmmm, aside from altidude differences, the horizon SHOULD be at the same distance for every one.

:D

And, seriously, you're right it seems.

:(
 
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