Author Topic: Los Angeles LED Lighting Effects  (Read 352 times)

Patrick Zhu

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Re: Los Angeles LED Lighting Effects
« Reply #15 on: January 18, 2018, 02:35:08 AM »
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LEDs should have low melting temperature so people must be careful with parabolic mirrors during the day around them...

Your post is just a joke, Right ??

rackramasca

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Re: Los Angeles LED Lighting Effects
« Reply #16 on: January 18, 2018, 05:02:51 AM »
Let me offer two cautionary points. How do we know that the two street scenes were imaged in exactly the same manner, with the same exposure time and camera chip sensitivity setting, etc? I can certainly generate nighttime images telling any kind of story I want these days through use of my Photoshop. So are these images truly objective, or perhaps purposely bias to favor LED installation?

Secondly, while LEDs might perhaps work favorably for L.A.'s perpetual summer, I can foresee real problems if LEDs are employed in less moderate climates. The LED's broad ground coverage and its bluish emission could virtually wipe out the night sky of any city that experienced a wintertime snow cover.

You know what you have already...but in half a century of the hobby I have never once seen a means of illumination, most touted to "improve" our lot, actually do so. Each has only made the situation worse.

BrooksObs

Alex Loftus

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Re: Los Angeles LED Lighting Effects
« Reply #17 on: January 18, 2018, 06:45:12 AM »
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Let me offer two cautionary points. How do we know that the two street scenes were imaged in exactly the same manner, with the same exposure time and camera chip sensitivity setting, etc? I can certainly generate nighttime images telling any kind of story I want these days through use of my Photoshop. So are these images truly objective, or perhaps purposely bias to favor LED installation?

Secondly, while LEDs might perhaps work favorably for L.A.'s perpetual summer, I can foresee real problems if LEDs are employed in less moderate climates. The LED's broad ground coverage and its bluish emission could virtually wipe out the night sky of any city that experienced a wintertime snow cover.

You know what you have already...but in half a century of the hobby I have never once seen a means of illumination, most touted to "improve" our lot, actually do so. Each has only made the situation worse.

BrooksObs

Up here where it is -40 Deg many times with 3' of snow cover it all still looks as it does in the summer. Night Sky Glow is still eliminated with the LED lighting. Surely there is some community close by that you can visit to see for yourself ? As the old saying goes " Don't knock it until you try it "! If the elected authorities have to stupe that low to dub / fudge something in they sure won't get away with it for too long this day and age !

fibcapoti

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Re: Los Angeles LED Lighting Effects
« Reply #18 on: January 20, 2018, 06:44:42 PM »
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Up here where it is -40 Deg many times with 3' of snow cover it all still looks as it does in the summer. Night Sky Glow is still eliminated with the LED lighting.
I doubt it! The point of full-cutoff lighting is to direct the light downward -- which is as it should be. But when there's snow under the light it bounces right back up again, and you end up little better than if the light weren't shielded.My measurements indicate an increase in sky brightnes of 75% or more immediately after a fresh snow. That decreases gradually as the snow is plowed and gets dirtier.

Davione Boone

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Re: Los Angeles LED Lighting Effects
« Reply #19 on: January 21, 2018, 04:12:18 AM »
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Up here where it is -40 Deg many times with 3' of snow cover it all still looks as it does in the summer. Night Sky Glow is still eliminated with the LED lighting.

I doubt it! The point of full-cutoff lighting is to direct the light downward -- which is as it should be. But when there's snow under the light it bounces right back up again, and you end up little better than if the light weren't shielded.
My measurements indicate an increase in sky brightnes of 75% or more immediately after a fresh snow. That decreases gradually as the snow is plowed and gets dirtier.
Yes but the light levels still might be a lot less in comparison to HPS or MV lighting and the surround lighting heads they are mounted on ! ? It might all be relative but the sky glow still looks a lot less, from a distance, to me when I am driving around and / or observing. Have you kept records to compare before and after readings over the years while changes were happening ? When you had the old lighting systems you had rebounds from the fresh snow and considerable light loss above the horizontal plane of the head, now with the new you only have a rebound and I would say that the snow does absorb some of this light as before but I would suspect that with new full cutoff heads and how they are placed to direct this new type / color of light there is quite a number difference overall in the sky above ?

Alex Manuel

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Re: Los Angeles LED Lighting Effects
« Reply #20 on: January 21, 2018, 06:31:02 AM »
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Up here where it is -40 Deg many times with 3' of snow cover it all still looks as it does in the summer. Night Sky Glow is still eliminated with the LED lighting. Surely there is some community close by that you can visit to see for yourself ? As the old saying goes " Don't knock it until you try it "! If the elected authorities have to stupe that low to dub / fudge something in they sure won't get away with it for too long this day and age !

Boy, oh boy, politicians sure must be a different breed up there in Canada! Down here south of the border many local politicians would sell out their own mothers to get a kick-back. And fudging "scientific" studies or canceling public hearings addressing them is standard practice. I can not tell you how many dirty deeds I've seen worked out in my suburban community over the years by both the town fathers and the school board. Get rid of one bad apple (if you can!) among them and two will replace him/her within just a couple of years!

As to the LEDs being an improvement over the current illuminatuion with snow on the ground, it'll definitely be a first if it turns out as you claim.

BrooksObs

Jeremy Kelley

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Re: Los Angeles LED Lighting Effects
« Reply #21 on: January 21, 2018, 08:18:11 AM »
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Up here where it is -40 Deg many times with 3' of snow cover it all still looks as it does in the summer. Night Sky Glow is still eliminated with the LED lighting. Surely there is some community close by that you can visit to see for yourself ? As the old saying goes " Don't knock it until you try it "! If the elected authorities have to stupe that low to dub / fudge something in they sure won't get away with it for too long this day and age !

Boy, oh boy, politicians sure must be a different breed up there in Canada! Down here south of the border many local politicians would sell out their own mothers to get a kick-back. And fudging "scientific" studies or canceling public hearings addressing them is standard practice. I can not tell you how many dirty deeds I've seen worked out in my suburban community over the years by both the town fathers and the school board. Get rid of one bad apple (if you can!) among them and two will replace him/her within just a couple of years!

As to the LEDs being an improvement over the current illuminatuion with snow on the ground, it'll definitely be a first if it turns out as you claim.

BrooksObs
Politicians are the same up here, if they can get away with it, but because of Internet access and every wide open aspect that goes with it things are getting harder and harder all the time to hide / deceive as you are surly well aware of, therefore these unscrupulous politicians are having not so easy times ! As I mentioned can you not see / study / compare for yourself this type of lighting somewhere close by ? It is a growing trend that is virtually changing / improving daily and it is / will work to improve, as a good alternative to the present systems that aren't and never will work in regards to light polution(s). Until something new comes along, as with everything else that is. LOL !

Jairo Zilinskas

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Re: Los Angeles LED Lighting Effects
« Reply #22 on: January 25, 2018, 01:38:19 PM »
I would also think that LED lighting could use sensors to automatically dim in areas of high reflection. Since the older lights were either on or off, I think this would be an improvement if utilized.

sdelbapaglo

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Re: Los Angeles LED Lighting Effects
« Reply #23 on: January 26, 2018, 01:36:08 AM »
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I would also think that LED lighting could use sensors to automatically dim in areas of high reflection. Since the older lights were either on or off, I think this would be an improvement if utilized.

It can be done ! The extra cost could easily be recouped.

witchcycsuti

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Re: Los Angeles LED Lighting Effects
« Reply #24 on: January 31, 2018, 06:18:03 AM »
I understand the snow reflection factor, but aren't your streets plowed soon after a snow? My brother lives in South Lake Tahoe, which averages 125 inches of snow per year. Their streets always get plowed after a snowfall, and after a couple of days, there is almost no snow on the street, even though there is plenty of snow on the landscape. So even though there is a lot of snow, there not too many nights in the winter where the street is snowy white.

Since cutoff LED fixtures radiate the majority of their light onto the street, wouldn't the most significant problem only be for a couple of days after snow?

When you look at the whole year, how many days out of the 365 have white streets? I guess that answer depends on where you live.

Wouldn't it be better to have a few days brightened by cut off LED lights shining on snowy streets than to have 365 days a year brightened by Cobra head HPS street lighting? Even if you have 90 days/year of snowy streets, isn't that better than having every day unnecessary LP from old non cut off fixtures?

Paul Rivera

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Re: Los Angeles LED Lighting Effects
« Reply #25 on: January 31, 2018, 07:55:28 AM »
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I understand the snow reflection factor, but aren't your streets plowed soon after a snow? My brother lives in South Lake Tahoe, which averages 125 inches of snow per year. Their streets always get plowed after a snowfall, and after a couple of days, there is almost no snow on the street ...
They may actually remove the snow and truck it away in Tahoe -- something that's done in some Canadian cities but in few U.S. cities. After the snow here is plowed, it ends up in a deep bank by the side of the road -- in other words, directly under the streetlights. And of course, lots of snow remains on the sidewalk side of the lights.

Akida Holland

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Re: Los Angeles LED Lighting Effects
« Reply #26 on: January 31, 2018, 09:14:35 AM »
My own city, Cambridge MA, is in the process of replacing the high-pressure sodium fixtures with LEDs. It's not a total loss, but on the whole the new lighting is clearly worse, for several reasons.First, the old HPS fixtures were in fact full-cutoff -- unlike the situation in many communities. The new LEDs definitely throw more light sideways than the old HPS fixtures. They can be shielded, but for some reasons you have to specially request a shield, instead of having all the fixtures shielded from the get-go.Second, the color temperature is much too blue. So although the total amount of light is probably no more than before, it seems much more noxious.Third, the team responsible evaluated streets for three different levels of lighting -- and were clearly itching to install as much lighting as possible. I live on a corner, and the smaller street is lighted fairly appropriately, but the larger street has been "upgraded" to a higher lighting level.On the good side, all the lights are turned down 50% at 10 p.m. Very sensible.By the way, the adjoining community of Arlington is also replacing all its lights, and doing a much better job. Possibly because they don't have as much money, so they couldn't hire "experts" to recommend too much light.A bunch of Cambridge citizens have banded together to try to fight the new lighting, but I'm not very heopeful. What's most irksome is that they left the whole thing to "experts" and never considered asking people beforehand what they would like.

unexaric

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Re: Los Angeles LED Lighting Effects
« Reply #27 on: February 03, 2018, 02:28:16 AM »
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I understand the snow reflection factor, but aren't your streets plowed soon after a snow? My brother lives in South Lake Tahoe, which averages 125 inches of snow per year. Their streets always get plowed after a snowfall, and after a couple of days, there is almost no snow on the street ...

They may actually remove the snow and truck it away in Tahoe -- something that's done in some Canadian cities but in few U.S. cities. After the snow here is plowed, it ends up in a deep bank by the side of the road -- in other words, directly under the streetlights. And of course, lots of snow remains on the sidewalk side of the lights.
They have a periodic truck away program up here but only the main streets / bus routes once they get filled in dangerously. You couldn't afford to truck away snow after every fall even a big fall, just off street plowing up onto the high snow bank until they encroach too much onto the driving lanes.

Chris Ingram

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Re: Los Angeles LED Lighting Effects
« Reply #28 on: February 03, 2018, 03:22:25 AM »
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My own city, Cambridge MA, is in the process of replacing the high-pressure sodium fixtures with LEDs. It's not a total loss, but on the whole the new lighting is clearly worse, for several reasons.
First, the old HPS fixtures were in fact full-cutoff -- unlike the situation in many communities. The new LEDs definitely throw more light sideways than the old HPS fixtures. They can be shielded, but for some reasons you have to specially request a shield, instead of having all the fixtures shielded from the get-go.
Second, the color temperature is much too blue. So although the total amount of light is probably no more than before, it seems much more noxious.
Third, the team responsible evaluated streets for three different levels of lighting -- and were clearly itching to install as much lighting as possible. I live on a corner, and the smaller street is lighted fairly appropriately, but the larger street has been "upgraded" to a higher lighting level.
On the good side, all the lights are turned down 50% at 10 p.m. Very sensible.
By the way, the adjoining community of Arlington is also replacing all its lights, and doing a much better job. Possibly because they don't have as much money, so they couldn't hire "experts" to recommend too much light.
A bunch of Cambridge citizens have banded together to try to fight the new lighting, but I'm not very heopeful. What's most irksome is that they left the whole thing to "experts" and never considered asking people beforehand what they would like.

We all agree that the old lighting systems were very bad, so why not give these new systems a chance, you might get to like the great reduction in sky glow which is what all the discussion is about on this and other forums. I would think they do not shield each and every light head due to what we all know as cost and the need for? Get out and away from your city and take some before and after pics as the change over process continues, you might be surprised in the end ! I worked in engineering for 42 yrs and there were always lots of experts, it's a fact of life, you are an expert also in your own field and subject to justified / unjustified criticism like the rest of us. It's the way of life, it has to get right once in a while don't you think ? It's all about when do you jump in and start the process ?

Ryan Chaudhari

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Re: Los Angeles LED Lighting Effects
« Reply #29 on: February 04, 2018, 11:30:37 AM »
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We all agree that the old lighting systems were very bad, so why not give these new systems a chance, you might get to like the great reduction in sky glow which is what all the discussion is about on this and other forums.
No, in fact Cambridge's old fully-shielded HPS lighting was just fine except that HPS is indisputably ugly. The color temperature is fine, but the way it's emitted in a few narrow lines ends up looking terrible.I haven't take enough sky readings to tell for sure, and the new lighting isn't fully in place. But I'm reasonably sure that it will end up increasing the skyglow.In any case, there are other reasons to like or dislike streetlighting besides its effect on skyglow. The new, blue LEDs are ugly, harsh, and probably have bad health effects -- something that matters more than astronomy.