Author Topic: A Good Light Pollution Discussion with Boston MAPC  (Read 180 times)

Theodore Inlaw

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A Good Light Pollution Discussion with Boston MAPC
« on: December 24, 2017, 12:35:41 AM »
Hi all:

Fantastic news.

I only had a phone conversation with the Energy Coordinator of the Clean Energy Division of the Boston Metropolitan Area Planning
Council (MAPC).  It had been very effective.  He sees the issue which blue-rich LEDs have on the environment, and can be conducive to performing
What he could to minimize the impact on the night sky, as well as the nocturnal aspect of the ecosystem.  Additionally, I made him conscious of the potential
Issues of disability glare,how it might impact the rising number of elderly drivers, and how weather conditions may make
Such glare more problematic.

He is open to considering the usage of blue-filtered LEDs as streetlights!  I gave him my contact information to the CEO of C&W Energy
Systems, which is the only manufacturer that knows the way to do this correctly.  I emphasized that Boston has the exciting opportunity to be
A significant role model for introducing good LED lighting which keeps the nighttime skies as best as one can expect for using LED technology.

He'll be amending the principles He developed for both towns and cities in his district to provide a lesser range of LED
Colour temperatures in their lamp selection.  Not sure what that range will be.  He also says these mild systems can or will be
Wireless so that light levels can be dropped later at night.  Cambridge is currently doing so, although their LEDs are pretty high at 4000K
color temperature.  He said that my time was perfect, because the towns in his jurisdiction are now carrying out an audit of their
Current lighting methods.

I offered my services to teach the communities under his authority about light contamination, through a webinar, etc..

I was quite happy with how the conversation went.

Gary



kondcongrese

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #1 on: December 24, 2017, 12:47:53 AM »
Filtered LEDs (FLED) <strong>can </strong>be a good solution if the purpose of reference is high heeled sodium (because it might be for many communities).  But make sure you specify the filtered<strong> warm white LED option</strong>, not the filtered <strong>cool white LED option</strong> offered by C & W.  The hot white filtered LED has a lumen-for-lumen impact on sky glow about 1.5 times high-pressure sodium (in other words, approximately a 50% growth).  With the increased application efficiencies possible with LED (that's from greater downward optical controller), reducing total lumen outputs by up to about 30% is achievable, bringing the net sky shine impact of the filtered warm white LED within 20% of that produced from the high heeled sodium lights being replaced.  Close at least.

Obviously, any fixture using any light source should be fully protected.

Unfortunately, when the purpose of reference is low-pressure sodium, either of these filtered LED options is not a good option.  The hot white filtered option (unfortunately, not the one seemingly used in Hawaii!) , the lumen to get lumen impact compared to LPS is 3.6 X, i.e. 260% growth in visible sky glow brightness.  For the research lying behind these figures refer to the webpage http://www.flagstaff...ight-pollution/ .

[Also regrettably in Hawaii, where professional astronomical concerns were foremost, the spectral breadth of these filtered LEDs (whether hot white or cool white) is a remarkable increase in spectral interference.  LPS, the tech being replaced in Hawaii, has a direct impact on only about 1-2 nm of the spectrum; to the filtered LEDs this increases to about 200 nm, or 200 times worse.  This in addition to the increased visibility of sky glow as explained above, of course.]

Unfortunately, now the entire sky glow analysis on the cool white filtered LED has not been done.  It can be expected to be substantially greater however than the filtered warm white LED clarified on the webpage above due to the much greater green content.

Further, the filtered warm white LED has a far more pleasant hue (to many people I believe) of a very light yellow, in place of the distinct green color of the filtered cool white LEDs.

Finally: we know that C & W is creating a filtered LED option with a more cutoff wavelength (we know about 550 nm, in place of the current 500 nm), in response to request from astronomers in the Canary islands.  This fixture is going to have a darker yellow colour, and a decrease sky glow impact.  Further, it might be an additional remarkable improvement on reducing different impacts such as circadian disturbance, etc., as both the blue and green parts of the spectrum have significant impact here.  We haven't seen spectral information for this particular product, so can't specifically quantify its effects.  It should be considered if it is available: ask C & W.

Maurice Deuschle

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #2 on: December 27, 2017, 01:58:24 PM »
Yes, C&amp;W has mentioned to me that they are developing a filtered LED that has more of an HPS look, with a CRI of 60 and efficacy of 90 lumens/watt.
None of the 20 cities I have talked with in the Boston area have any interest in LPS. It's LED all the way. Hopefully some balance can be achieved. Filtered
is better than non-filtered when it comes to controlling Rayleigh scatter and mitigating sky glow. I'd take the soft-greenish color of HI to what I have in HPS
lighting outside my house if it means getting rid of the blue spectral content. Besides, green is my favorite color.

Hopefully the night sky at my observing location outside of my town will improve. I'd be happy enough to just have that.

~G.

Carl Hanks

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #3 on: December 27, 2017, 11:31:12 PM »
No-one is interested in LPS because, primarily, of a relentless decades-long campaign of bad mouthing by the American lighting industry. But that's a story for another thread, one I won't start. The basic practical reality is as you noted.

Here are spectral radiace distibutions for the C&amp;W 500nm-filtered cool-white and warm-white products, along with HPS.
The blue+green content [radiance(350-550nm)/radiance(350-770nm)] for these is:

source || percent&lt;550nm
HPS || 9%
FLEDww || 14%
FLEDcw || 25%

Though, indeed, filtered is better than unfiltered LED, both of these products produce substantially more blue+green than HPS, ~50% more and 180% more. The reason the FLEDcw appears green is because, well, it has a lot of green. HPS has much less. [These quick calculations have not been adjusted to equal luminous - photopic - output, so if that was done the ratios would probably be somewhat different, but the basic point would not be changed.]

BTW - the implicit definition of "blue" as &lt;500nm, often seen in LED discussions, though strictly correct when describing visual (photopic) color, is too narrow from the visual sky glow perspective. A vastly more useful metric for sky glow brightness is the scotopic/photopic ratio:

source || S/P
HPS || 0.60
FLEDww || 0.96
FLEDcw || 1.22

These S/P ratios track very closely with the sky glow ratios. So you see Hawai'i traded LPS (S/P = 0.24) for FLEDcw, and if lumens are equal then skyglow has increased 1.22/0.24 ~ 5x. Yes, they also got rid of the poorly shielded LPS fixtures, which may have reduced skyglow by ~1/2 - net skyglow is then ~2.5x brighter instead of 5x.

And, contrary to initial expectations of many, the differing sky glow brightness of these different sources has almost nothing to do with Rayleigh scattering. If you want to read more about why, look at the Luginbuhl et al. paper linked on this page: http://www.flagstaff...ight-pollution/ . The basic point is that the increased scattering is almost exactly balanced by increased absorption when viewed from nearby (which shouldn't be a surprise, since they are essentially different words for the same thing).

So, finally, if you can get Boston to go with FLED, the C&amp;W FLEDww (500nm filter) is much better for sky glow than the FLEDcw - as noted previously about equal to HPS. And the straw-yellow color is probably more pleasing than green to most. If they could use a FLED with a 550nm cutoff filter, then they would certainly noticeably reduce visual sky glow.


Troy Furlong

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #4 on: December 28, 2017, 09:38:10 AM »
Quote
No-one is interested in LPS because, primarily, of a relentless decades-long campaign of bad mouthing by the American lighting industry. But that's a story for another thread, one I won't start. The basic practical reality is as you noted.

Here are spectral radiace distibutions for the C&amp;W 500nm-filtered cool-white and warm-white products, along with HPS.

CnW FLEDww FLEDcw and HPS.png

The blue+green content [radiance(350-550nm)/radiance(350-770nm)] for these is:

source || percent&lt;550nm
HPS || 9%
FLEDww || 14%
FLEDcw || 25%

Though, indeed, filtered is better than unfiltered LED, both of these products produce substantially more blue+green than HPS, ~50% more and 180% more. The reason the FLEDcw appears green is because, well, it has a lot of green. HPS has much less. [These quick calculations have not been adjusted to equal luminous - photopic - output, so if that was done the ratios would probably be somewhat different, but the basic point would not be changed.]

BTW - the implicit definition of "blue" as &lt;500nm, often seen in LED discussions, though strictly correct when describing visual (photopic) color, is too narrow from the visual sky glow perspective. A vastly more useful metric for sky glow brightness is the scotopic/photopic ratio:

source || S/P
HPS || 0.60
FLEDww || 0.96
FLEDcw || 1.22

These S/P ratios track very closely with the sky glow ratios. So you see Hawai'i traded LPS (S/P = 0.24) for FLEDcw, and if lumens are equal then skyglow has increased 1.22/0.24 ~ 5x. Yes, they also got rid of the poorly shielded LPS fixtures, which may have reduced skyglow by ~1/2 - net skyglow is then ~2.5x brighter instead of 5x.

And, contrary to initial expectations of many, the differing sky glow brightness of these different sources has almost nothing to do with Rayleigh scattering. If you want to read more about why, look at the Luginbuhl et al. paper linked on this page: http://www.flagstaff...ight-pollution/ . The basic point is that the increased scattering is almost exactly balanced by increased absorption when viewed from nearby (which shouldn't be a surprise, since they are essentially different words for the same thing).

So, finally, if you can get Boston to go with FLED, the C&amp;W FLEDww (500nm filter) is much better for sky glow than the FLEDcw - as noted previously about equal to HPS. And the straw-yellow color is probably more pleasing than green to most. If they could use a FLED with a 550nm cutoff filter, then they would certainly noticeably reduce visual sky glow.

Sorry, I think that your assessment of LPS is wishful thinking. The reason it's unpopular isn't because of propaganda; it's because it's unspeakably hideous. I like HPS just fine -- though my wife finds even that profoundly ugly. But I wouldn't wish LPS on my worst enemy. All in all, I would rather have our new 4000K LEDs. Though 2400K would be best by far.

dogswargersdurch

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #5 on: December 30, 2017, 09:43:23 PM »
Quote
Quote

No-one is interested in LPS because, primarily, of a relentless decades-long campaign of bad mouthing by the American lighting industry. ........

So, finally, if you can get Boston to go with FLED, the C&amp;W FLEDww (500nm filter) is much better for sky glow than the FLEDcw - as noted previously about equal to HPS. And the straw-yellow color is probably more pleasing than green to most. If they could use a FLED with a 550nm cutoff filter, then they would certainly noticeably reduce visual sky glow.

Sorry, I think that your assessment of LPS is wishful thinking. The reason it's unpopular isn't because of propaganda; it's because it's unspeakably hideous. I like HPS just fine -- though my wife finds even that profoundly ugly. But I wouldn't wish LPS on my worst enemy. All in all, I would rather have our new 4000K LEDs. Though 2400K would be best by far.

I've not seen an LPS streetlight - or parking lot orsecuritylight -in30 years!

...but anyway.... I doubt very much that HPS, LPS, or any discharge tube lights will even be made soon.So few will sell that it just won't be profitable to make them.Maybe in China? After all they still make steam engines (our local railroad bought one for fan runs!).

So, the future is LED and that's were we should put our efforts, including a discussion of color, shielding, experimentally determined minimum light levels for public safety, smart lighting controls. Here in New York, following up on the recent law requiring the state to determine minimum lighting levels and then not to exceed them, the Assembly members who fought that effort are now going to introduce a bill pushing the requirements down to local level - and it will include color of LEDs and light trespass.

While sky glow is important to folks like me (in rural southern NY my nearest street light is over a mile away, in northern NY there are maybe 25 streetlights inside a circle of 50 miles in diameter around me, with most of the land being wilderness - I have far more bears and moose than streetlights), light trespass is an important issue to city and suburb dwellers. For such people (probably most reading this) sky glow is a limited annoyance compared to the streetlight next to the house blasting into their yard.

....and anyway.... the recent sat images for my southern digs area (NY/PA border) shows that by far the brightest source of LP (much brighter than the city of Binghamton, pop 75,000) is the gas frack'ing fields of Pennsylvania! We have mostly empty forested mountains producing more light than a small city - and even worse - the sky glow flickers like crazy! Nothing like trying to do a CCD image a mile from a gas flame taller than a 10 story building, on a drilling pad lit up much brighter than daylight..... with more of 'um every few miles.......

ryarejalo

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #6 on: January 03, 2018, 06:54:30 PM »
Quote
Quote

Quote

No-one is interested in LPS because, primarily, of a relentless decades-long campaign of bad mouthing by the American lighting industry. ........

So, finally, if you can get Boston to go with FLED, the C&amp;W FLEDww (500nm filter) is much better for sky glow than the FLEDcw - as noted previously about equal to HPS. And the straw-yellow color is probably more pleasing than green to most. If they could use a FLED with a 550nm cutoff filter, then they would certainly noticeably reduce visual sky glow.

Sorry, I think that your assessment of LPS is wishful thinking. The reason it's unpopular isn't because of propaganda; it's because it's unspeakably hideous. I like HPS just fine -- though my wife finds even that profoundly ugly. But I wouldn't wish LPS on my worst enemy. All in all, I would rather have our new 4000K LEDs. Though 2400K would be best by far.

I've not seen an LPS streetlight - or parking lot orsecuritylight -in30 years!
I see LPS street and parking lot lights every day in Flagstaff, Sedona, Cottonwood, all of Coconino County (which is the 2nd largest county in the US after Los Angeles County), etc. Please remember that it's just not the blue that causes health and environmental problems. It's the blue part of the spectrum, too.

Debra (past IDA BOD)

olexecin

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #7 on: January 04, 2018, 03:30:20 PM »
As an update, I had earlier suggested to my contact at the Boston MAPC that he should at least reach out to Dr. Bob Adams at C&amp;W Energy Solutions to hear him out regarding the benefits of going for blue-filtered LEDs. Well, I just heard back from Bob, who tells me that he will indeed be having a phone conversation with the MAPC contact tomorrow!

Hey, I am fully aware that it may go no where. But at least, for now, there is a chance for real change for the Boston metropolitan area. Whereas before I stepped up to the plate, there was none.

~Gary

creasseinicomp

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #8 on: January 04, 2018, 06:19:20 PM »
Quote
Quote

No-one is interested in LPS because, primarily, of a relentless decades-long campaign of bad mouthing by the American lighting industry. ........

So, finally, if you can get Boston to go with FLED, the C&amp;W FLEDww (500nm filter) is much better for sky glow than the FLEDcw - as noted previously about equal to HPS. And the straw-yellow color is probably more pleasing than green to most. If they could use a FLED with a 550nm cutoff filter, then they would certainly noticeably reduce visual sky glow.

Sorry, I think that your assessment of LPS is wishful thinking. The reason it's unpopular isn't because of propaganda; it's because it's unspeakably hideous. I like HPS just fine -- though my wife finds even that profoundly ugly. But I wouldn't wish LPS on my worst enemy. All in all, I would rather have our new 4000K LEDs. Though 2400K would be best by far.

I've not seen an LPS streetlight - or parking lot orsecuritylight -in30 years![/quote]
I see LPS street and parking lot lights every day in Flagstaff, Sedona, Cottonwood, all of Coconino County (which is the 2nd largest county in the US after Los Angeles County), etc. Please remember that it's just not the blue that causes health and environmental problems. It's the blue part of the spectrum, too.

Debra (past IDA BOD)

I've lived in most parts of the country - Wisconsin, Illinois, Missouri, Massachusetts, Hawaii, Florida, California, and Arizona. I've also traveled quite a bit inside and outside the U.S. The only places were I've seen LPS lighting are some communities in Arizona, San Diego County, San Jose, and the Big Island of Hawaii. I love LPS lighting, but most people don't. I can't imagine that LPS will still be produced in the 2020s. In my opinion expending too much energy on the virtues of LPS is a bit like fighting the last war. The battle front has moved on to LED lighting and color temperature.[/quote]

Matthew Danielson

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #9 on: January 09, 2018, 03:12:55 PM »
Aside from color, it's important to minimize light output and use tight cutoffs so that light doesn't go where it's not useful.

explacgarco

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #10 on: January 10, 2018, 06:16:23 AM »
Quote
Aside from color, it's important to minimize light output and use tight cutoffs so that light doesn't go where it's not useful.

I agree. Full cutoff is always the most important specification, with color temperature being the secondary (but important) target to shoot for. Ironically the importance of full cutoff was well understood as early as 1918, although the term had not yet been coined. Here is how it was stated in the first roadway lighting manual ever written, by the Holophane Glass Company:

        "It is very important to see to is that the street lighting system produces an effect which surrounds
         the eyes of those using the streets with conditions under which the eye is free to perform its
         functions properly. Any system which fails in this respect is extravagant - no matter how
         efficient the lamps nor how efficiently the light may be directed upon the street surfaces or
         objects. Glare serves to seriously reduce the discerning power of the eye".BTW, do you know that in California they do not light the entire freeway? Only interchanges, on ramps, and off ramps are lit. Most people that go to California never even notice, demonstrating how unnecessary most freeway lighting really is. My own impression is that by lighting only interchanges and access ramps, safety is improved because a subconscious message is sent to the brain to increase attention in these areas, where threats are greater. It's not possible for the brain to maintain a sustained level of attention over an extended period of time, so I think having these subconscious cues is very useful.

frenafverbi

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Re: A Good Light Pollution Discussion with Boston MAPC
« Reply #11 on: January 11, 2018, 05:43:33 AM »
Quote
BTW, do you know that in California they do not light the entire freeway? Only interchanges, on ramps, and off ramps are lit.

I find this practice even worse.  While in the interchange I get blinded by light and can't see into the dark where the light ends. I then need to re-dark adapt and while driving half blinded.  I tend to just be getting my night vision back just in time for the next interchange and start the process all over again.