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La Palma in the Canary Islands passed a law in 1988 "to protect the quality of the night sky for the purpose of astrophysical observation" [1]. This seemed prim

La Palma in the Canary Islands passed a law in 1988 "to protect the quality of the night sky for the purpose of astrophysical observation" [1]. This seemed primarily for the benefit of large international optical observatories on the island. Not sure how they're that's faring after the recent volcanic eruption, but the law seemed quite strictly enforced when I visited a few years ago - streetlightling intensity was low and there were very few (if any) floodlit buildings. [1] https://www.starsislandlapalma.es/en/the-island/the-sky-starlight-reserve/ https://www.starsislandlapalma.es/en/the-island/the-sky-star...

seanmcdirmid 5y ago
Tucson Arizona is well known for having a strong night sky protection law. It sure makes the street lights in that city very different.
- piptastic 5y ago
  Kyba and colleagues found that streetlights accounted for just 13 percent of the city’s total light visible after midnight. That number would jump to 18 percent if the city did not dim the lights. This means most of the light is coming from other types of artificial lighting. https://earthobservatory.nasa.gov/images/148259/experimenting-with-tucson-night-lights https://earthobservatory.nasa.gov/images/148259/experimentin...
  - seanmcdirmid 5y ago
    Yes. External house lighting, especially in higher-than-average-crime Arizona, is probably going to keep the numbers up. Also headlights from cars, though there shouldn't be much of that past midnight.
    - labster 5y ago
      Do external lights prevent or reduce crime? If so, by how much?
      - treeman79 5y ago
        Ever walk around in a bad area at night with few lights? My experience. Was waking in what I thought was a decent area. As soon as sun dropped sketchy looking character were everywhere. Just standing around doing nothing. I assume selling drugs. When I got back to an area with better lighting they were all gone.
        fennecs 5y ago
        If you are in a bad area you are in a bad area. Just seems like correlation.
        treeman79 5y ago
        Lots of downtowns are very different depending on time
        seanmcdirmid 5y ago
        Two things: * You don't want your house to be the juiciest target. Having lights prevent it from standing out as a place where someone could just hide in the shadows. * Lights make your cameras more effective. I'm not really living in a bad area (town homes go for around $1 million here), but we are close enough to a large unhoused and/or drug-seeking population that we still get a lot of property crime (mainly smash and grab on street-parked cars, but you see people going around looking into houses as well). So while everyone on my street is fairly wealthy (and can be relied on to let you know if something is wrong), we still have to do our due diligence (lights, motion lighting, cameras).
        labster 5y ago
        Lots of anecdata here but no actual data. If it’s just something that moves crime around, then it’s just people lowering their personal risk to let others pay the externalities. Or maybe external lights reduce the absolute amount of crime. I don’t know.
        5y ago
  - TheRealPomax 5y ago
    Why make it sound like cutting down light pollution by a whopping 15% is somehow not significant. If anything, this article explains that there's an obvious and simple way to reduce light pollution by quite a bit. It doesn't ever require passing any legislation for heaven's sake, it's just a Thursday afternoon municipal planning decision with roll-out spread over a four year period or something to keep costs trivially manageable.
    - mynameisvlad 5y ago
      Who said it's not significant? They're just saying it might not be significant enough to drastically affect the type of lights used, as GP comment implied.
    - piptastic 5y ago
      Here's why from later down: “Light-pollution activists and governments have been very focused on street lighting, and that makes sense because it’s probably the biggest single source and the government has direct control over it,” Kyba said. “But my worry is that most of the growth in light is coming from other applications. If we want to reduce the environmental impact of outdoor lighting, it’s not good enough to change to LED streetlights and then stop. We need to think critically about all the different types of light sources there are.”
      - TheRealPomax 5y ago
        Right, but that's still a weird way to focus on it. Of course it's not enough, but it's a fantastic easy step in a multi-step solution.
  - joe_the_user 5y ago
    As far as I can tell, Tucson's sky protection regulations aren't limited to stopping streetlights. "With major astronomical observatories within close range, city leaders enacted an outdoor lighting ordinance in 2012 that requires fully shielded lighting and sets limits on the total light produced at night, especially in natural areas and areas close to astronomy sites." Edit: The gp does mention street lights in the second sentence but that doesn't imply that's all that's done. And hey, no, that's not all the Tucson does. https://www.darksky.org/nights-over-tucson/ https://www.darksky.org/nights-over-tucson/
- lizknope 5y ago
  Kitt Peak Observatory is 50 miles west. When I went on the tour they said that they get more light pollution from Phoenix 140 miles north than from Tucson. The streetlights in Tucson have covers that direct the light downward which also saves energy because you are not wasting the light going up into the sky where it doesn't help any people.

seanmcdirmid 5y ago

Tucson Arizona is well known for having a strong night sky protection law. It sure makes the street lights in that city very different.

piptastic 5y ago
Kyba and colleagues found that streetlights accounted for just 13 percent of the city’s total light visible after midnight. That number would jump to 18 percent if the city did not dim the lights. This means most of the light is coming from other types of artificial lighting. https://earthobservatory.nasa.gov/images/148259/experimenting-with-tucson-night-lights https://earthobservatory.nasa.gov/images/148259/experimentin...
- seanmcdirmid 5y ago
  Yes. External house lighting, especially in higher-than-average-crime Arizona, is probably going to keep the numbers up. Also headlights from cars, though there shouldn't be much of that past midnight.
  - labster 5y ago
    Do external lights prevent or reduce crime? If so, by how much?
    - treeman79 5y ago
      Ever walk around in a bad area at night with few lights? My experience. Was waking in what I thought was a decent area. As soon as sun dropped sketchy looking character were everywhere. Just standing around doing nothing. I assume selling drugs. When I got back to an area with better lighting they were all gone.
      - fennecs 5y ago
        If you are in a bad area you are in a bad area. Just seems like correlation.
        treeman79 5y ago
        Lots of downtowns are very different depending on time
        seanmcdirmid 5y ago
        Two things: * You don't want your house to be the juiciest target. Having lights prevent it from standing out as a place where someone could just hide in the shadows. * Lights make your cameras more effective. I'm not really living in a bad area (town homes go for around $1 million here), but we are close enough to a large unhoused and/or drug-seeking population that we still get a lot of property crime (mainly smash and grab on street-parked cars, but you see people going around looking into houses as well). So while everyone on my street is fairly wealthy (and can be relied on to let you know if something is wrong), we still have to do our due diligence (lights, motion lighting, cameras).
        labster 5y ago
        Lots of anecdata here but no actual data. If it’s just something that moves crime around, then it’s just people lowering their personal risk to let others pay the externalities. Or maybe external lights reduce the absolute amount of crime. I don’t know.
        5y ago
- TheRealPomax 5y ago
  Why make it sound like cutting down light pollution by a whopping 15% is somehow not significant. If anything, this article explains that there's an obvious and simple way to reduce light pollution by quite a bit. It doesn't ever require passing any legislation for heaven's sake, it's just a Thursday afternoon municipal planning decision with roll-out spread over a four year period or something to keep costs trivially manageable.
  - mynameisvlad 5y ago
    Who said it's not significant? They're just saying it might not be significant enough to drastically affect the type of lights used, as GP comment implied.
  - piptastic 5y ago
    Here's why from later down: “Light-pollution activists and governments have been very focused on street lighting, and that makes sense because it’s probably the biggest single source and the government has direct control over it,” Kyba said. “But my worry is that most of the growth in light is coming from other applications. If we want to reduce the environmental impact of outdoor lighting, it’s not good enough to change to LED streetlights and then stop. We need to think critically about all the different types of light sources there are.”
    - TheRealPomax 5y ago
      Right, but that's still a weird way to focus on it. Of course it's not enough, but it's a fantastic easy step in a multi-step solution.
- joe_the_user 5y ago
  As far as I can tell, Tucson's sky protection regulations aren't limited to stopping streetlights. "With major astronomical observatories within close range, city leaders enacted an outdoor lighting ordinance in 2012 that requires fully shielded lighting and sets limits on the total light produced at night, especially in natural areas and areas close to astronomy sites." Edit: The gp does mention street lights in the second sentence but that doesn't imply that's all that's done. And hey, no, that's not all the Tucson does. https://www.darksky.org/nights-over-tucson/ https://www.darksky.org/nights-over-tucson/
lizknope 5y ago
Kitt Peak Observatory is 50 miles west. When I went on the tour they said that they get more light pollution from Phoenix 140 miles north than from Tucson. The streetlights in Tucson have covers that direct the light downward which also saves energy because you are not wasting the light going up into the sky where it doesn't help any people.