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When did light pollution start to be a serious problem?

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#76 Kent10

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Posted 07 December 2018 - 05:11 PM

We have new LED street lights in Flagstaff, Arizona, which is a Dark Sky City.  The city installed them in my neighborhood 1st and wanted feedback.  They are yellow or orange in color and are not supposed to effect the night sky.  We have the Lowell Observatory here so that is important.

 

I don't know yet if they actually do affect the night sky.  Can you trust the city?  smile.gif I have been taking readings and can't get readings as dark as I used to but it could be because it is winter and we have neighborhood smoke and snow and Christmas lights that might also affect the sky.

 

Yes, the LED lights can be turned down but they haven't done that.  They did it on one light in our neighborhood as a test and it was somewhat less bright.  Some noticed it and some didn't so the dimming isn't substantial and this is on level 0.  The lights are a lot brighter than what we had and when my wife and I go for walks at night we don't like all the glare.  Not much we can do.  I have been working with the city and there is the possibility of only using lights at intersections for our neighborhood but this depends on feedback from the community and I have my doubts that most will want this even in Flagstaff.  People seem to feel safer with more light.



#77 HarryRik9

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Posted 07 December 2018 - 05:20 PM

Where I live, people are out at night walking in the dark without carrying lights and without clothing that reflects light, so they can be seen. Do you think that they appreciate the need for less light pollution when they ignore their own personal safety? We need more and brighter lights not fewer and dimmer lights! I am more afraid of hitting a pedestrian at night than worried about light pollution.

 

By the way. If you hit a dog, that is as bad as hitting a person given the attitude about keeping animals safe. 



#78 Kent10

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Posted 07 December 2018 - 05:33 PM

One of the concerns for Flagstaff is, if we do have fewer street lights will homeowners turn their lights on more.  Already we have lots of home lights on 24 hours a day.  Being a Dark Sky City, there are rules/laws.  I don't know what they are exactly but the director of Lowell mentioned that there are rules but no one enforces them, yet.  They talked about perhaps trying to enforce them but how that would happen I am not sure.  The lights probably have to be aimed and shielded so they don't light up the sky is my guess.  There are lights that are sky friendly sold at Home Depot from what I was told, and these lights still light up the house and streets well.  It would be nice if they were used.  I don't know if they cost more.  That would be a problem for some.  But I think many people don't know they exist.


Edited by Kent10, 07 December 2018 - 05:40 PM.


#79 Starman1

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Posted 07 December 2018 - 05:35 PM

One light study commissioned by the IDA showed that a particular street was very brightly lit.

A test of pedestrians and visibility showed many were invisible until they stepped in the path of the car.

In the test, they replaced all the lights with lights 1/3 as bright.

Surprisingly, all the pedestrians were far more visible and easier to avoid.

The reasons given were:

--lower light level reduced the glare in the eyes of the motorists by reducing intensity and scatter from dust on the windshield

--it lowered the intensity of shadows, making things in the shadows far more visible

--it allowed the motorist to maintain a tad more night vision

--it reduced the reflection of light from other cars, buildings, etc., reducing glare and scatter.

 

So was the cure more light?  No, it was LESS light.

 

In Los Angeles, there is a street in Hollywood which replaced all the street lights with reflectorized full cut-off fixtures.

As you drive along the street, you cannot directly see any light until you are very near it--I'd estimate a fraction of a second before you are directly underneath it.

The actual lumens from each light was reduced about 50%  from the older lights.

A poll taken of commuters who travel the street found:

--most people thought the street was better illuminated

--most people thought they could see parked cars and pedestrians a lot better than before.

--most people thought their safety had gone up because glare in their windshields was pretty much gone.

I've driven that street as well, and it is a marvel that the street is so well illuminated with no sensation of actually looking directly at the lights.

I think it's safer, too, and it is easier to see the walkways on either side.  And that, with 50% LESS light.

 

So you don't need more and brighter lights.  You need more intelligent lighting.

 

You can read more about it here:

https://www.darksky.org

under the headers "Light Pollution" and "Lighting".


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#80 HarryRik9

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Posted 07 December 2018 - 06:04 PM

Don, You said this: So you don't need more and brighter lights.  You need more intelligent lighting.

 

I agree absolutely. But, after having been on the board of my HOA, and opposed brighter lights, they hated me. It is hard to oppose brighter and more lights, when the Police Department says more and brighter lights increases public safety. Given the lack of intelligence of people walking their dogs at night without proper safety precautions, I can understand that viewpoint.



#81 Starman1

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Posted 07 December 2018 - 06:19 PM

Here is an essay I penned for my HOA on lighting and I bring it up at every meeting:

http://www.crestwood...restwood-hills/

We just had the first 2 streetlights put up in my HOA.  We had gone 70+ years without one in an area of 375 homes (we're a red zone oasis in a white zone)

There are now lawsuits to get them taken down, but I'm not sure they will prevail.

The lighting is of the good kind, but we are a very hilly neighborhood, and the lighting is visible for a mile or two down the hill.

We had just had a spate of burglary/break-ins in the neighborhood and everyone is scared to death.

All the break-ins occurred during the day and they caught the gang involved, but it doesn't matter.

As you say, they want more and brighter lights.  


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#82 bumm

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Posted 08 December 2018 - 10:05 AM

Don, You said this: So you don't need more and brighter lights.  You need more intelligent lighting.

 

I agree absolutely. But, after having been on the board of my HOA, and opposed brighter lights, they hated me. It is hard to oppose brighter and more lights, when the Police Department says more and brighter lights increases public safety. Given the lack of intelligence of people walking their dogs at night without proper safety precautions, I can understand that viewpoint.

The answer isn't in accepting ignorance, it's attempting to educate.  The police are wrong.  Those people walking their dogs would be safer with more intelligent lighting.

                                                                                                                               Marty


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#83 Redbetter

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Posted 08 December 2018 - 10:18 AM

Red :

 

I'm well aware of the winter Milky Way. I measure at a variety of elevations and note the effect of the Milky Way .

 

What I am seeing is an overall increased brightness at all elevations. At other times of the year , the sky may measure 21.3 at 45 degrees,  last night it was under 21.0 

 

I suspect it may be due to increased upper level moisture or something similar. 

 

Jon

 

I managed to outwit the forecast and headed up despite what it said...my guess was an unexpected late afternoon clearing would develop into mid elevation fog and freezing temps higher would result in clear sky above 6,000 feet.  Nailed it!  whee.gif  I drove through a fog later at 3-4K on the way up just as I expected, and lower on the way down.  I still had to contend with dew then frost as the temps dropped, but the valley fog gave me the darkest readings I have had at this site, 21.75 MPSAS somewhat off zenith (to avoid the Milky Way which read 21.55.)  21.65 or greater is what I expect from the site when the air is clean and the Milky Way is not overhead.  The gegenschein stood out despite it approaching the bright bands of Milky Way. 

 

For comparison I was also seeing low values (bright) in town the previous night during a short clearing--similar to the delta you reported.  But it was apparent that there was still a lot of moisture in the air because NELM was depressed and their were periodic haze overs before if went full overcast.  So, my tentative conclusion is that the issue this month is primarily atmospheric moisture.  In recent years December was colder and drier here IIRC.  We were getting multi-night hard freezes about this time. This year we are running ~15 F warmer at night.    



#84 Jon Isaacs

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Posted 08 December 2018 - 12:35 PM

For comparison I was also seeing low values (bright) in town the previous night during a short clearing--similar to the delta you reported.  But it was apparent that there was still a lot of moisture in the air because NELM was depressed and their were periodic haze overs before if went full overcast.  So, my tentative conclusion is that the issue this month is primarily atmospheric moisture.  In recent years December was colder and drier here IIRC.  We were getting multi-night hard freezes about this time. This year we are running ~15 F warmer at night.

 

I saw the same thing last year.  It could be moisture but it doesn't correlate to local low level humidity and weather pagterns.

Jon



#85 Starman1

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Posted 08 December 2018 - 02:06 PM

a new record for me last night in Los Angeles:

Dark adapted peripheral vision saw magnitude 3 stars (!) and the SQM got a reading of 16.2.

That's about the same as my dark site 30 minutes after sunset.  

Sheesh.

It was light scatter due to a huge amount of water vapor in the air that bordered on, but was not quite, fog.


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#86 Jon Isaacs

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Posted 08 December 2018 - 05:06 PM

Don:

 

What's a good night for your home up on the hill?

 

A very good night for our place I San Diego is 18.8.

 

Jon



#87 Starman1

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Posted 08 December 2018 - 05:35 PM

I vary from 16.8-17.8, normally.

I've seen an 18.2 once, when the air was superlatively clear and marine layer clouds covered west LA below me (I'm at 850').

My due south is over ocean, as is my SW, so I get good views in that direction (only Santa Catalina and San Clemente islands).

I can even see Canopus when it culminates.

Alas, the W/SW is the direction the marine layer clouds come in from, so somewhere past the meridian, everything often winks out.

My E/SE is very bright.  The SQM-L reads 16.0 or brighter nearly 100% of the time at 45°.

 

One compensation: being on the boundary between oceanic and land air masses, I often get superlative seeing.

I have used my 4" refractor at 238x a lot in the last year.


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#88 vsteblina

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Posted 08 December 2018 - 10:24 PM

Jeez, and I pretty much have given up on my 20.4 skies in town.

 

I am considering moving operations to my cabin, 10 miles from town and a 21.4 sky.

 

Guess I will have to quit complaining and just start observing more.



#89 JuergenB

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Posted 09 December 2018 - 05:45 AM

Reverting to the original question: even before the invention of electric lighting, there was gas lighting in the major European cities. This started in the 19th century. At the end of the 19th century, the invention of the incandescent mantle led to an increase of the light output of gas lanterns. Lastly I have been in my hometown Düsseldorf, Germany, where gas lighting, now with natural gas, is still operated in old town quarters. I found that the light was very mild and comfortable, although not dim. I can imagine that besides the fact that much less people were living in the city around 1900, light pollution must have existed already but to a much lesser extent.

 

Most German cities got rid of gas lighting in the 1960s because they wanted to be modern. Presently, we have still 80,000 gas lanterns in German cities, most in Berlin (36,600), followed by Düsseldorf (16,000). The city of Düsseldorf decided in 1990 to stay with those gas lanterns "because of the continuous spectrum and the ancient look wich matches the historic town scape".

 

Jürgen


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#90 bumm

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Posted 09 December 2018 - 08:25 AM

Jurgen, the gas lighting sounds beautiful.  Funny that people can't learn that dimmer lighting can be effective even when they're standing in it.  I'll be the first to admit that SOME outdoor lighting is vital for safe travel, even if crime prevention is questionable.  And being something of a nostalgic history nut, some old streetlights are very attractive.  My little town in rural Iowa has acorn lights on it's Main Street downtown for historical reasons.  OK, I can tolerate that, but WHY DID THEY HAVE TO PUT OVERLY BRIGHT LED BULBS IN 'EM???  You can hardly see the buildings...

     I'd have to say that even gas lighting would have a negative effect on astronomy, but the advent of electric lighting made things much worse.  As for a particular date, I don't think there is one.  It's just gotten worse, and worse, and worse...

                                                                                              Marty


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#91 Achernar

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Posted 09 December 2018 - 10:00 AM

It has been a growing problem ever since the advent of electrical powered lighting. By the 1930's it was already a serious problem for professional astronomers in the U.S., but for amateurs it has been a major problem at least as far back as the 1960's. The advent of LED lights will probably render observing the vast majority of deep sky objects nearly impossible in my area within the next ten or twenty years.

 

Taras




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