> 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.<p>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.<p>By the way, if you don’t know, Lowell Observatory in Flagstaff is where Pluto was discovered.
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.
> “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.”<p>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).<p>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.<p>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.
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.<p>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 :).
> 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.<p>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.
Are there no orange/yellow LEDs? Seems odd, since LEDs were red long before other colors were available.<p>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.
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.
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.
I can't stand the orange glow of old street lights. You can see so much better with 4300k vs 2000k <a href="http://i.imgur.com/JsSCfFp.jpg" rel="nofollow">http://i.imgur.com/JsSCfFp.jpg</a><p><a href="https://www.youtube.com/watch?v=U1dMlVwUsrA" rel="nofollow">https://www.youtube.com/watch?v=U1dMlVwUsrA</a>
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.
> 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.<p>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.
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.
They also have a dark sky ordinance where various rules, to point lights downward, covers over the tops of them, etc.<p>More cities should do this, it makes for lovely night skies where you can actually see the stars.
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?