10 ms·

Flagstaff, Arizona, switched to LEDs without giving astronomers a headache

218 points by lnguyen 7y ago

retSava 7y ago
This year we (our family) have the expressed goal of renting a cabin far off from major cities (partly) so our daughter will get to see a night sky full of stars. We live close to an airport, so atm she gets excited by seeing more than 10-ish stars, so I'm looking forward to seeing her reaction :). Also, once seeing and pointing out a satellite was a highlight :).
- _Microft 7y ago
  You might want to show her the International Space Station. It's very bright and NASA offers a notification service [1] for overflys at your location. Having people on it might give bonus points. Extra info: on November, 2nd, it will be the 19th year of uninterrupted human presence off the Earth. [1] https://spotthestation.nasa.gov/ https://spotthestation.nasa.gov/ PS: you might want to watch out for the next group of Starlink satellites from SpaceX. The chain of sparkles moving silently over the sky was absolutely amazing to watch. It's most likely not dark-sky compatible, though :/
  - sokoloff 7y ago
    Another helpful site (be sure to try the green button) https://james.darpinian.com/satellites/ https://james.darpinian.com/satellites/
- daemin 7y ago
  One thing I'm thankful of when living and growing up in Australia, you could clearly see the night sky and all the stars there if you went to the beach or the hills. Far less ambient light pollution, such a beautiful night sky. I just hope it doesn't get spoiled by all those constellations of Internet Satellites.
  - Ididntdothis 7y ago
    Australia also has the advantage of seeing more of the galactic core during the whole year. On the northern hemisphere you can see it only in the summer and even then less than Australia.
  - ceejayoz 7y ago
    Australia has far less air pollution, too, given the low population and relatively tiny strip of populated areas along the coast. The skies in Freycinet National Park in Tasmania were the most stunning I've ever seen in my life.
- hunter-gatherer 7y ago
  I don't knowknow where you are located, but Wyoming has some dark skies and beauitful camp sites if you can make it that way. A guy I went to bootcamp with in my Army days was born and raised in the city. One of our first nights in the field I remember he was astounded at the number of stars. I guess like your daughter, he had only ever seen a few at a time his entire life. He actually thought shooting stars were something that Hollywood contrived. So myself and another guy stayed up a little bit with him until he saw one. His mind almost exploded.
  - eth0up 7y ago
    A great way to "explode" the mind routinely is a pair of 15x70 binoculars with premium optics. The effect of handing them to someone, nudging them to Orion's belt or Pleiades, etc, and hearing the inevitable expletive never gets old. Continues to work on self indefinitely, for me.
    - bradstewart 7y ago
      Recommendations for a good pair?
      - eth0up 7y ago
        Entry price will be near $400 for what I was referencing. Mine were Garrett Optical (Signature Series), which I think is no more. However, the build is almost identical under different brands, eg Orion Resolux. The features in these porro prism 15x70 models, for an equivalent, should be: Fully multi coated; waterproof; bak-4; individual diopter focus. Garrett was meticulous in testing collimation before shipping, which is critical for quality viewing at higher magnification. I had the Resolux too, but in 10x70, which were great, but not as wow. When I can afford it, I will buy the Fujinon Polaris 16x70 ($900), unless I stumble into great wealth, in which case I may consider the largest pair of roof prism Leica available. The well-built porro style binos are best equipped with a monopod for extended viewing, due to their weight. Roof-prism binos are lighter, but much more expensive and rare in large apertures, ie objective lens. I briefly had a pair of Zeiss Victory (roof prism) 10x50 which were phenomenal, highly portable and stunningly clear, but simply couldn't provide the wowness of the 15x70. Ideally, I'd have both. Edit: Whatever you choose, my advice is to never even consider "zoom" as a feature in any pair of binoculars. It is tempting in concept, but almost never conducive to quality.
- Merrill 7y ago
  There is nothing like a moonless winter night (<20 below) in far rural Minnesota. Either you get a vast number of stars or you get the Northern Lights. Eastern North Dakota is probably a good choice as well.
berti 7y ago
Aside from the sky glow aspects, I really dislike cool blue lighting. I've just had my office upgraded to warm white LEDs and it's really noticeable every time I walk into a colleague's office with "cool daylight" coloured lighting.
- TheSpiceIsLife 7y ago
  My friends call me The Illuminazi for my habit of swapping everyones fluoros and compact fluoros our for 2700K ones. It’s an expense I’m happy to pay.
  - brobdingnagians 7y ago
    One of the best benefits of working from home for me is that I can have the lighting I prefer (4000k, with both my light and screen set to the same color temp). But if I ever go back to an office I'm stealing this idea.
    - TheSpiceIsLife 7y ago
      Have you ever tried blue blocking glasses? Personally I’d prefer rose-coloured glasses.
      - JustSomeNobody 7y ago
        Even just a 10% brown on your regular glasses makes a noticeable difference.
      - brobdingnagians 7y ago
        I did try blue blocking glasses awhile back, didn't seem to work well for me, but I should try them again since I've become more aware of how things affect me now.
- 9HZZRfNlpR 7y ago
  I very much prefer working in cold white and whee I relax and rest there I prefer warm white. I think cold white helps me stay awake and more alert. It all might be s placebo of course.
_Microft 7y ago
That's not only dark-sky- but also insect-friendly! Insects are attracted by blueish lights which, for example, the old sodium pressure lamps did not emit. (The orange light you might remember from those were the 589nm double spectral lines of sodium.) LEDs can/do emit blueish lights and should be picked carefully for outdoor lighting.
rapnie 7y ago
> “What's left is green,” Hall said. “And so you stand under this and it's like the zombie apocalypse, because everybody's green. They've gone to these in Hilo, Hawaii, and we were standing in a parking lot trying to talk to each other, and it's just like straight out of Night of the Living Dead.” This is not my experience. In The Netherlands green LED's are applied more and more often for streetlighting in rural areas and surveillance of building construction sites (light pole + camera). First time encounter takes some getting used to, because we are so familiar with orange Sodium hue. But I find they make the night landscape more peaceful and serene looking. Green spectrum is perfect for the human eye. You see more detail and sharper focus, seems to me (compared to orange). Apparently its also good for nature. Not only to insects, but also birds not getting distracted.
- jacobolus 7y ago
  Orange is a lot better if you want to keep your night vision and be able to see into the shadows (or e.g. look at the stars with your unassisted eyes).
  - brandmeyer 7y ago
    Contrary to popular belief, cyan is better for night vision. Your rods are most sensitive to cyan, so you can use much dimmer cyan light than you can use red/orange light. http://stlplaces.com/night_vision_red_myth/ http://stlplaces.com/night_vision_red_myth/
    - jacobolus 7y ago
      The question is not what you can see best with the least energy, but what kind of glare in your peripheral vision will cause bright-adaptation. Your page there seems to be based on its author looking at the sentitivity curves for rods and cones and then speculating, but not as far as I can tell based on experimental evidence about how well the eyes stay dark-adapted. Edit: Moreover, the type of lamps appropriate for medium-bright street lighting and the type of lamps appropriate for briefly turning on to dimly see your camera gear while you fiddle with it when you are out taking night-sky photographs are quite different. Disclaimer: I am not an expert on triggers for brightness adaptation. I should try to hunt up some research papers sometime.) Looks like https://www.osapublishing.org/josa/abstract.cfm?uri=josa-41-6-402 https://www.osapublishing.org/josa/abstract.cfm?uri=josa-41-... is a reasonable place to start looking into the citation graph. https://scholar.google.com/scholar?cites=4424978361272323417 https://scholar.google.com/scholar?cites=4424978361272323417 Or maybe https://www.sciencedirect.com/science/article/pii/S0042698977800011 https://www.sciencedirect.com/science/article/pii/S004269897... https://scholar.google.com/scholar?cites=14694116360901580947 https://scholar.google.com/scholar?cites=1469411636090158094...
acollins1331 7y ago
5k possy represent
snowwrestler 7y ago
> Older streetlights are high-pressure sodium bulbs, which produce a warm yellow glow around a color temperature of 2,000 K... Many of the LED streetlights on the market have much cooler color temperatures of 3,000 or even 4,000 K. I feel like referring to 2,000 K bulbs as “warm” and 5,000 K bulbs as “cool” has got to be one of the worst screw-ups between scientific terms and common terms in English. And probably a missed opportunity to embed some latent understanding of thermodynamics in the broader culture.
- htfu 7y ago
  Warm/cool color theory predates the kelvin scale, so it might be more accurate to say you feel Celsius' flipping his original scale was the screwup? But as how it is now makes that much more sense, and since you couldn't really have a kelvin version of such a thing anyways, maybe chalk it down as just one of those things. In any case no one could convince me to call the color of fire and the sun anything but warm, and that of snow and sea cold.
  - wlesieutre 7y ago
    >In any case no one could convince me to call the color of ... snow and sea cold. How about the color of a gas stove flame? Maybe we should have called them "warm white" and "hot white" instead.
    - htfu 7y ago
      Yeah warm to hot is good but again runs into clashing with things established before much had been said about black-body radiation. Just because it might not be conductive to a neat 1:1 mapping with scientific common sense doesn't have to mean either should change. Quirks are fun!
      - wlesieutre 7y ago
        I'm used to it myself, but I work in architectural lighting and I can't count how many times I've had to explain that "warm white" is the low temperatures and "cool white" is the high temperatures. It's a frequent nuisance for me, but not a huge deal and we're stuck with it. If we were going to make people put in some effort and redefine fix stupid quirks that exist out of historical convention, I'd put that effort toward adopting metric instead of switching words for shades of white :P It's not like switching cool and hot would make sense either, 2700K (orangeish) is 4400°F and 5000K (blueish) is 8540°F. Neither of those is anything near a "cool" temperature. "Blazing white" and "inferno white"?
movieswebsite 7y ago
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dmazin 7y ago
> The bulbs Flagstaff relied on for most of its streetlights were low-pressure sodium—a variant that only emits light at a single wavelength (589 nanometers) near that yellow color, producing something resembling candlelight. Even 10 years after college I distinctly remember the look of Flagstaff at night. Namely because the city was effectively grayscale and it was beautiful. By the way, if you don’t know, Lowell Observatory in Flagstaff is where Pluto was discovered.
- nullc 7y ago
  > Even 10 years after college I distinctly remember the look of Flagstaff at night. Namely because the city was effectively grayscale and it was beautiful. San Jose used to look that way too. There are still pockets of LPS lights here and there, but since most makes are not commercially available anymore as of this year you can expect they'll vanish fairly quickly. Such a loss, LPS streelighting was very good. I hope the narrowband amber LEDs are a commercial success. Anyone know where there are fixtures with them available in small quantity? ... I stocked up on LPS bulbs before they went unavailble, but they won't last forever.
  - emelski 7y ago
    I found that the LPS lighting in San Jose was very close in color to yellow traffic signals, which made it sometimes confusing (and therefore more dangerous) to drive there after dark.
seanalltogether 7y ago
> Another way to do it is with phosphor coatings on the LED that absorb light of one wavelength and emit it at another wavelength. Lights known as phosphor-converted amber (PCA) shift all the light out of the blue and into the yellow part of the spectrum at the cost of some efficiency. Is this essentially an LED filament bulb? I've replaced all lights in my house now with LED filaments because they look more natural and are omnidirectional.
- theatrus2 7y ago
  It has nothing to do with filaments and is all with the phosphor coating. Standard white LEDs intentionally bleed the base blue LED through, whereas PCA LEDs do not. Lumileds is the primary innovator for PCA (and other offshoots). https://www.lumileds.com/uploads/571/DS144-luxeon-c-color-line-datasheet-pdf https://www.lumileds.com/uploads/571/DS144-luxeon-c-color-li...
sparker72678 7y ago
It’s a real shame that Phoenix metro is going to ruin everything for Flagstaff and Tucson in the not-too-distant future by refusing to implement any light limits at all.
- deleted 7y ago
  [deleted]
- driverdan 7y ago
  How is that going to ruin things for Flagstaff? Phoenix is far away from Flagstaff.
  - sparker72678 7y ago
    > The Greater Phoenix area casts a nighttime arc of light over most of Arizona, extending more than 200 miles in each direction. https://www.azcentral.com/story/news/local/arizona/2014/09/07/arizona-dark-skies-disappearing/15158485/ https://www.azcentral.com/story/news/local/arizona/2014/09/0...
  - sachdevap 7y ago
    Dark skies require a pretty high radius of dark landmass. For an estimate of the extent of this, try seeing the areas around major cities here: https://www.lightpollutionmap.info/ https://www.lightpollutionmap.info/
  - sh-run 7y ago
    I live in Dallas-Fort Worth and grew up near Amarillo, TX. In high school I regularly drove a few miles (like less than 5) away from the city to look at lights. I've noticed in DFW you've got to get much much further away from the city. I can't really put a number on it, but I know even 20 miles out of town you can still only see the brightest stars.
  - antognini 7y ago
    Former astronomer here. From Mt. Graham in Arizona you can see the sky glow from Los Angeles. Phoenix is a lot closer than that.
post_break 7y ago
I can't stand the orange glow of old street lights. You can see so much better with 4300k vs 2000k http://i.imgur.com/JsSCfFp.jpg http://i.imgur.com/JsSCfFp.jpg https://www.youtube.com/watch?v=U1dMlVwUsrA https://www.youtube.com/watch?v=U1dMlVwUsrA
- simonebrunozzi 7y ago
  There are places where I would strongly disagree with you, like my home town Assisi, in Italy [0]. But for everything else, you are quite right. [0]: https://www.flickr.com/photos/126687494@N08/15010177954/ https://www.flickr.com/photos/126687494@N08/15010177954/
- KingMachiavelli 7y ago
  Exactly, I really don't know why we bother to put up lights that aren't enough illumination to do without headlights/flashlight and most of the light is just wasted to the sky and illuminating the sides of buildings.
- Paianni 7y ago
  The light distribution from old LPS/SOX fixtures was usually all over the shop. A crucial benefit with LEDs is that their output is much easier to control thanks to their small size, and accordingly most lanterns have 'cut-off' optics.
Merrill 7y ago
Are there no orange/yellow LEDs? Seems odd, since LEDs were red long before other colors were available. Years ago, Pickett slide rules were a greenish yellow, which, according to their advertising, was the color that provided the sharpest visual acuity and comfort for the user. Maybe that would provide the best vision for the least lumens as well.
- gmiller123456 7y ago
  >...was the color that provided the sharpest visual acuity I think it changes considerably based on the environment and the user. I do some 10 meter air rifle competition, and the sighs have filters in them to let you choose different colors. I can notice a big difference based on the lighting, and at a competition different people will have settled on different colors.
LinuxBender 7y ago
Do the new street lights only have LED's, or do they also have cameras and microphones like the ones installed in San Diego and a few other cities for machine learning?
pkaye 7y ago
Flagstaff is the only city so far I've actually been able to see the milky way. We just got lucky one night while visiting as the sky was clear at the Lowell observatory.
notadoc 7y ago
They also have a dark sky ordinance where various rules, to point lights downward, covers over the tops of them, etc. More cities should do this, it makes for lovely night skies where you can actually see the stars.
codereflection 7y ago
Seattle replaced all streetlights with LEDs a few years back. It too bad that they are the blue lighting that the article mentions, which absolutely makes viewing anything in the sky a lot harder than it already was. I'd love to go back to Flagstaff some day to see the lighting in person.
Zamicol 7y ago
https://imgur.com/oYYRmHl.png https://imgur.com/oYYRmHl.png

218 points by lnguyen 7y ago

This year we (our family) have the expressed goal of renting a cabin far off from major cities (partly) so our daughter will get to see a night sky full of stars. We live close to an airport, so atm she gets excited by seeing more than 10-ish stars, so I'm looking forward to seeing her reaction :). Also, once seeing and pointing out a satellite was a highlight :).

_Microft 7y ago
You might want to show her the International Space Station. It's very bright and NASA offers a notification service [1] for overflys at your location. Having people on it might give bonus points. Extra info: on November, 2nd, it will be the 19th year of uninterrupted human presence off the Earth. [1] https://spotthestation.nasa.gov/ https://spotthestation.nasa.gov/ PS: you might want to watch out for the next group of Starlink satellites from SpaceX. The chain of sparkles moving silently over the sky was absolutely amazing to watch. It's most likely not dark-sky compatible, though :/
- sokoloff 7y ago
  Another helpful site (be sure to try the green button) https://james.darpinian.com/satellites/ https://james.darpinian.com/satellites/
daemin 7y ago
One thing I'm thankful of when living and growing up in Australia, you could clearly see the night sky and all the stars there if you went to the beach or the hills. Far less ambient light pollution, such a beautiful night sky. I just hope it doesn't get spoiled by all those constellations of Internet Satellites.
- Ididntdothis 7y ago
  Australia also has the advantage of seeing more of the galactic core during the whole year. On the northern hemisphere you can see it only in the summer and even then less than Australia.
- ceejayoz 7y ago
  Australia has far less air pollution, too, given the low population and relatively tiny strip of populated areas along the coast. The skies in Freycinet National Park in Tasmania were the most stunning I've ever seen in my life.
hunter-gatherer 7y ago
I don't knowknow where you are located, but Wyoming has some dark skies and beauitful camp sites if you can make it that way. A guy I went to bootcamp with in my Army days was born and raised in the city. One of our first nights in the field I remember he was astounded at the number of stars. I guess like your daughter, he had only ever seen a few at a time his entire life. He actually thought shooting stars were something that Hollywood contrived. So myself and another guy stayed up a little bit with him until he saw one. His mind almost exploded.
- eth0up 7y ago
  A great way to "explode" the mind routinely is a pair of 15x70 binoculars with premium optics. The effect of handing them to someone, nudging them to Orion's belt or Pleiades, etc, and hearing the inevitable expletive never gets old. Continues to work on self indefinitely, for me.
  - bradstewart 7y ago
    Recommendations for a good pair?
    - eth0up 7y ago
      Entry price will be near $400 for what I was referencing. Mine were Garrett Optical (Signature Series), which I think is no more. However, the build is almost identical under different brands, eg Orion Resolux. The features in these porro prism 15x70 models, for an equivalent, should be: Fully multi coated; waterproof; bak-4; individual diopter focus. Garrett was meticulous in testing collimation before shipping, which is critical for quality viewing at higher magnification. I had the Resolux too, but in 10x70, which were great, but not as wow. When I can afford it, I will buy the Fujinon Polaris 16x70 ($900), unless I stumble into great wealth, in which case I may consider the largest pair of roof prism Leica available. The well-built porro style binos are best equipped with a monopod for extended viewing, due to their weight. Roof-prism binos are lighter, but much more expensive and rare in large apertures, ie objective lens. I briefly had a pair of Zeiss Victory (roof prism) 10x50 which were phenomenal, highly portable and stunningly clear, but simply couldn't provide the wowness of the 15x70. Ideally, I'd have both. Edit: Whatever you choose, my advice is to never even consider "zoom" as a feature in any pair of binoculars. It is tempting in concept, but almost never conducive to quality.
Merrill 7y ago
There is nothing like a moonless winter night (<20 below) in far rural Minnesota. Either you get a vast number of stars or you get the Northern Lights. Eastern North Dakota is probably a good choice as well.

berti 7y ago

Aside from the sky glow aspects, I really dislike cool blue lighting. I've just had my office upgraded to warm white LEDs and it's really noticeable every time I walk into a colleague's office with "cool daylight" coloured lighting.

TheSpiceIsLife 7y ago
My friends call me The Illuminazi for my habit of swapping everyones fluoros and compact fluoros our for 2700K ones. It’s an expense I’m happy to pay.
- brobdingnagians 7y ago
  One of the best benefits of working from home for me is that I can have the lighting I prefer (4000k, with both my light and screen set to the same color temp). But if I ever go back to an office I'm stealing this idea.
  - TheSpiceIsLife 7y ago
    Have you ever tried blue blocking glasses? Personally I’d prefer rose-coloured glasses.
    - JustSomeNobody 7y ago
      Even just a 10% brown on your regular glasses makes a noticeable difference.
    - brobdingnagians 7y ago
      I did try blue blocking glasses awhile back, didn't seem to work well for me, but I should try them again since I've become more aware of how things affect me now.
9HZZRfNlpR 7y ago
I very much prefer working in cold white and whee I relax and rest there I prefer warm white. I think cold white helps me stay awake and more alert. It all might be s placebo of course.

_Microft 7y ago

That's not only dark-sky- but also insect-friendly! Insects are attracted by blueish lights which, for example, the old sodium pressure lamps did not emit. (The orange light you might remember from those were the 589nm double spectral lines of sodium.) LEDs can/do emit blueish lights and should be picked carefully for outdoor lighting.

rapnie 7y ago

> “What's left is green,” Hall said. “And so you stand under this and it's like the zombie apocalypse, because everybody's green. They've gone to these in Hilo, Hawaii, and we were standing in a parking lot trying to talk to each other, and it's just like straight out of Night of the Living Dead.” This is not my experience. In The Netherlands green LED's are applied more and more often for streetlighting in rural areas and surveillance of building construction sites (light pole + camera). First time encounter takes some getting used to, because we are so familiar with orange Sodium hue. But I find they make the night landscape more peaceful and serene looking. Green spectrum is perfect for the human eye. You see more detail and sharper focus, seems to me (compared to orange). Apparently its also good for nature. Not only to insects, but also birds not getting distracted.

jacobolus 7y ago
Orange is a lot better if you want to keep your night vision and be able to see into the shadows (or e.g. look at the stars with your unassisted eyes).
- brandmeyer 7y ago
  Contrary to popular belief, cyan is better for night vision. Your rods are most sensitive to cyan, so you can use much dimmer cyan light than you can use red/orange light. http://stlplaces.com/night_vision_red_myth/ http://stlplaces.com/night_vision_red_myth/
  - jacobolus 7y ago
    The question is not what you can see best with the least energy, but what kind of glare in your peripheral vision will cause bright-adaptation. Your page there seems to be based on its author looking at the sentitivity curves for rods and cones and then speculating, but not as far as I can tell based on experimental evidence about how well the eyes stay dark-adapted. Edit: Moreover, the type of lamps appropriate for medium-bright street lighting and the type of lamps appropriate for briefly turning on to dimly see your camera gear while you fiddle with it when you are out taking night-sky photographs are quite different. Disclaimer: I am not an expert on triggers for brightness adaptation. I should try to hunt up some research papers sometime.) Looks like https://www.osapublishing.org/josa/abstract.cfm?uri=josa-41-6-402 https://www.osapublishing.org/josa/abstract.cfm?uri=josa-41-... is a reasonable place to start looking into the citation graph. https://scholar.google.com/scholar?cites=4424978361272323417 https://scholar.google.com/scholar?cites=4424978361272323417 Or maybe https://www.sciencedirect.com/science/article/pii/S0042698977800011 https://www.sciencedirect.com/science/article/pii/S004269897... https://scholar.google.com/scholar?cites=14694116360901580947 https://scholar.google.com/scholar?cites=1469411636090158094...

acollins1331 7y ago

5k possy represent

snowwrestler 7y ago

> Older streetlights are high-pressure sodium bulbs, which produce a warm yellow glow around a color temperature of 2,000 K... Many of the LED streetlights on the market have much cooler color temperatures of 3,000 or even 4,000 K. I feel like referring to 2,000 K bulbs as “warm” and 5,000 K bulbs as “cool” has got to be one of the worst screw-ups between scientific terms and common terms in English. And probably a missed opportunity to embed some latent understanding of thermodynamics in the broader culture.

htfu 7y ago
Warm/cool color theory predates the kelvin scale, so it might be more accurate to say you feel Celsius' flipping his original scale was the screwup? But as how it is now makes that much more sense, and since you couldn't really have a kelvin version of such a thing anyways, maybe chalk it down as just one of those things. In any case no one could convince me to call the color of fire and the sun anything but warm, and that of snow and sea cold.
- wlesieutre 7y ago
  >In any case no one could convince me to call the color of ... snow and sea cold. How about the color of a gas stove flame? Maybe we should have called them "warm white" and "hot white" instead.
  - htfu 7y ago
    Yeah warm to hot is good but again runs into clashing with things established before much had been said about black-body radiation. Just because it might not be conductive to a neat 1:1 mapping with scientific common sense doesn't have to mean either should change. Quirks are fun!
    - wlesieutre 7y ago
      I'm used to it myself, but I work in architectural lighting and I can't count how many times I've had to explain that "warm white" is the low temperatures and "cool white" is the high temperatures. It's a frequent nuisance for me, but not a huge deal and we're stuck with it. If we were going to make people put in some effort and redefine fix stupid quirks that exist out of historical convention, I'd put that effort toward adopting metric instead of switching words for shades of white :P It's not like switching cool and hot would make sense either, 2700K (orangeish) is 4400°F and 5000K (blueish) is 8540°F. Neither of those is anything near a "cool" temperature. "Blazing white" and "inferno white"?

movieswebsite 7y ago

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dmazin 7y ago

> The bulbs Flagstaff relied on for most of its streetlights were low-pressure sodium—a variant that only emits light at a single wavelength (589 nanometers) near that yellow color, producing something resembling candlelight. Even 10 years after college I distinctly remember the look of Flagstaff at night. Namely because the city was effectively grayscale and it was beautiful. By the way, if you don’t know, Lowell Observatory in Flagstaff is where Pluto was discovered.

nullc 7y ago
> Even 10 years after college I distinctly remember the look of Flagstaff at night. Namely because the city was effectively grayscale and it was beautiful. San Jose used to look that way too. There are still pockets of LPS lights here and there, but since most makes are not commercially available anymore as of this year you can expect they'll vanish fairly quickly. Such a loss, LPS streelighting was very good. I hope the narrowband amber LEDs are a commercial success. Anyone know where there are fixtures with them available in small quantity? ... I stocked up on LPS bulbs before they went unavailble, but they won't last forever.
- emelski 7y ago
  I found that the LPS lighting in San Jose was very close in color to yellow traffic signals, which made it sometimes confusing (and therefore more dangerous) to drive there after dark.

seanalltogether 7y ago

> Another way to do it is with phosphor coatings on the LED that absorb light of one wavelength and emit it at another wavelength. Lights known as phosphor-converted amber (PCA) shift all the light out of the blue and into the yellow part of the spectrum at the cost of some efficiency. Is this essentially an LED filament bulb? I've replaced all lights in my house now with LED filaments because they look more natural and are omnidirectional.

theatrus2 7y ago
It has nothing to do with filaments and is all with the phosphor coating. Standard white LEDs intentionally bleed the base blue LED through, whereas PCA LEDs do not. Lumileds is the primary innovator for PCA (and other offshoots). https://www.lumileds.com/uploads/571/DS144-luxeon-c-color-line-datasheet-pdf https://www.lumileds.com/uploads/571/DS144-luxeon-c-color-li...

sparker72678 7y ago

It’s a real shame that Phoenix metro is going to ruin everything for Flagstaff and Tucson in the not-too-distant future by refusing to implement any light limits at all.

deleted 7y ago
[deleted]
driverdan 7y ago
How is that going to ruin things for Flagstaff? Phoenix is far away from Flagstaff.
- sparker72678 7y ago
  > The Greater Phoenix area casts a nighttime arc of light over most of Arizona, extending more than 200 miles in each direction. https://www.azcentral.com/story/news/local/arizona/2014/09/07/arizona-dark-skies-disappearing/15158485/ https://www.azcentral.com/story/news/local/arizona/2014/09/0...
- sachdevap 7y ago
  Dark skies require a pretty high radius of dark landmass. For an estimate of the extent of this, try seeing the areas around major cities here: https://www.lightpollutionmap.info/ https://www.lightpollutionmap.info/
- sh-run 7y ago
  I live in Dallas-Fort Worth and grew up near Amarillo, TX. In high school I regularly drove a few miles (like less than 5) away from the city to look at lights. I've noticed in DFW you've got to get much much further away from the city. I can't really put a number on it, but I know even 20 miles out of town you can still only see the brightest stars.
- antognini 7y ago
  Former astronomer here. From Mt. Graham in Arizona you can see the sky glow from Los Angeles. Phoenix is a lot closer than that.

post_break 7y ago

I can't stand the orange glow of old street lights. You can see so much better with 4300k vs 2000k http://i.imgur.com/JsSCfFp.jpg http://i.imgur.com/JsSCfFp.jpg https://www.youtube.com/watch?v=U1dMlVwUsrA https://www.youtube.com/watch?v=U1dMlVwUsrA

simonebrunozzi 7y ago
There are places where I would strongly disagree with you, like my home town Assisi, in Italy [0]. But for everything else, you are quite right. [0]: https://www.flickr.com/photos/126687494@N08/15010177954/ https://www.flickr.com/photos/126687494@N08/15010177954/
KingMachiavelli 7y ago
Exactly, I really don't know why we bother to put up lights that aren't enough illumination to do without headlights/flashlight and most of the light is just wasted to the sky and illuminating the sides of buildings.
Paianni 7y ago
The light distribution from old LPS/SOX fixtures was usually all over the shop. A crucial benefit with LEDs is that their output is much easier to control thanks to their small size, and accordingly most lanterns have 'cut-off' optics.

Merrill 7y ago

Are there no orange/yellow LEDs? Seems odd, since LEDs were red long before other colors were available. Years ago, Pickett slide rules were a greenish yellow, which, according to their advertising, was the color that provided the sharpest visual acuity and comfort for the user. Maybe that would provide the best vision for the least lumens as well.

gmiller123456 7y ago
>...was the color that provided the sharpest visual acuity I think it changes considerably based on the environment and the user. I do some 10 meter air rifle competition, and the sighs have filters in them to let you choose different colors. I can notice a big difference based on the lighting, and at a competition different people will have settled on different colors.

LinuxBender 7y ago

Do the new street lights only have LED's, or do they also have cameras and microphones like the ones installed in San Diego and a few other cities for machine learning?

pkaye 7y ago

Flagstaff is the only city so far I've actually been able to see the milky way. We just got lucky one night while visiting as the sky was clear at the Lowell observatory.

notadoc 7y ago

They also have a dark sky ordinance where various rules, to point lights downward, covers over the tops of them, etc. More cities should do this, it makes for lovely night skies where you can actually see the stars.

codereflection 7y ago

Seattle replaced all streetlights with LEDs a few years back. It too bad that they are the blue lighting that the article mentions, which absolutely makes viewing anything in the sky a lot harder than it already was. I'd love to go back to Flagstaff some day to see the lighting in person.

Zamicol 7y ago

https://imgur.com/oYYRmHl.png https://imgur.com/oYYRmHl.png