Greenhouses here in the lower mainland of British Columbia have been devastating to the night sky. It's quite depressing how little society values the night sky, something that's been an important part of every human culture for longer than recorded history. I've taken friends out to thoroughly mediocre skies (Bortle 4-5) and they've been very impressed, because they're used to city lights (Bortle 9) where you can maybe see a few of the brightest stars and planets.

If you've never seen truly dark skies, do yourself a favour and go see what they look like during true night. Bring binoculars if you have them, maybe get a planisphere and a (dim!) red flashlight.

The lack of respect for the night sky includes starlink and the other internet providers dumping tens of thousands of satellites in orbit instead of building municipal internet, by the way. It's been a huge hit to the field of astronomy. Before someone inevitably says "we should just be putting telescopes in orbit", orbital observatories are obviously a huge deal and I support building more of them, but you simply can't put things like the ELT (40m primary mirror, 2800 tonnes) or the Square Kilometre Array in space.

• qurren

  yesterday at 6:00 PM

  Starlink gets a lot of flax for it but as an avid night sky photographer myself (IG: @dheeranet) who regularly goes to Bortle 1 parts of the world, I haven't found them to be an issue at all.

  1. They are only visible when they are spinning up to orbit

  2. They are too dim to desensitize your eyes, and are extremely easy to remove with the most basic of outlier rejection techniques; netizens often amplifiy outliers by max-stacking instead of outlier-rejected mean-stacking to make Starlink look much worse than it is

  3. Lights from planes have ALWAYS been much, much, much, much worse than satellites. They still aren't particularly a problem for imaging if you know how to outlier reject, and their paths are known, predictable and trackable

  I'm not an Elon-fan or anything but just giving a dose of objective reality here.

  Not to detract from TFA's real issue which is light pollution from cities -- that's an actual issue as the regions of dark sky are shrinking.

  • NooneAtAll3

    yesterday at 10:36 PM

    > They are only visible when they are spinning up to orbit

    > and are extremely easy to remove with the most basic of outlier rejection techniques; netizens often amplifiy outliers by max-stacking instead of outlier-rejected mean-stacking to make Starlink look much worse than it is

    my understanding was that they are a problem on much bigger scale than yours "one dude with mobile telescope (or maybe just a camera?)"

    sure, we don't have many film observatories anymore (where max-stacking is literally only thing they can do), but a lot of lower-to-medium scale observatories get polluted observations with not enough funding to clean up easily or too small FoV for cleanup to matter - frame gets ruined, observation needs to be longer for effect

    • esikich

      yesterday at 11:32 PM

      I don't see how this can be true especially if you have a fancy telescope tracking something, take 3-5 whatever many shots in succession and stack. It's astrophotography 101.

      • thayne

        today at 12:46 AM

        For professional astronomers, it really sucks if you only have, say, an hour of observing time on a big telescope, and then a few of your precious frames are ruined because of a satellite. And you don't always even know that the frame is ruined until later, or have the flexibility to take more frames if needed (because you submit the full observation plan ahead of time, and just get the results later), in which case one bad frame can mean you don't have enough good frames to get valuable data.

        Or more generally, let's say 10% of frames have satellite noise. That means there is 10% less observing you can do in a night. For amateurs, that is annoying. For professionals, that means less science can be done.

        • esikich

          today at 1:52 AM

          That's what I don't understand, how are they ruined? If you're so deep that you need minutes or hours of exposures, that satellite will blip past the frame so fast it's not going to matter. And if the exposure time is less than that, you stack.

          • thayne

            today at 2:58 AM

            1. The satellite is usually significantly brighter than the thing you are observing. Often bright enough to saturate pixels (which can spill over to adjacent pixels).

            2. If you are doing photometry (measuring the brightness of something), even if the relative brightness isn't very much, it can introduce a lot of noise to the data. For many things, even the dimmest satellite is going to add more light than the change in brightness you are looking for.

            Now to be fair for scientific research typically you can use the frame if the streak isn't too close to your object(s) of interest. And for pretty pictures you can often edit out the streaks. But even so, it's a problem more than you would think.

            • esikich

              today at 3:33 AM

              Is this what you do? Because I'm at least an intermediate with astrophotography with a camera, and even airplanes are a total non issue. If you're so deep into the sky that you actually need many minutes or hours on the same spot, the teeny tiny time that satellite is there is a non issue and easy to remove with math.

              • thayne

                today at 3:45 AM

                Not any more. But in college I worked in an astronomy research group.

  • Reason077

    yesterday at 9:55 PM

    As a “night sky enthusiast”, as opposed to a real astronomer, Starlink and other satellites do not bother me much.

    There’s certainly more of them than there used to be, but the satellites aren’t bright enough to affect your eyes or distract too much from the stars. If you do see one it’s a fun little exercise to try and figure out what it is!

    Ground-based light sources are the real threat to night skies.

  • culi

    yesterday at 10:10 PM

    Starlink has over 10k currently but has applied for at least 42k. And because it's now a US military technology, every other country is building its own. China is planning on launching over 12k satellites and Russia is working on their own.

    It's too much

    • bdamm

      yesterday at 11:29 PM

      Deep dusk will be quite a disco ball.

  • garbagewoman

    yesterday at 8:00 PM

    Both are real issues, to be clear. LEO satellites are a real and increasing issue.

    • parl_match

      yesterday at 9:40 PM

      Yes, but one is a vastly smaller issue than the status quo issues.

      Starlink gets a lot of attention because it's new, and because it's run by a polarizing guy who sucks.

      Meanwhile, the airplane and streetlight situation has been destroying night sky photography for decades, to the point where photographers consult charts and have communities tracking the best times of years to minimize the hours of driving you have to do.

      But let's "both are real issues" it, sure.

      • culi

        yesterday at 10:13 PM

        It's an exponentially growing issue. Starlink's current fleet of ~10k is expected to grow to at least 42k. And since its been used for military uses, China and Russia have realized they also need their own competition. China's SpaceSail plans on launching 15k satellites by 2030. The EU's ambitions are much smaller than both of them, but if every developing nation continues to build their own platform, where does it end?

        • parl_match

          yesterday at 10:54 PM

          > where does it end

          It still won't be as big of an issue for night sky photography, for reasons mentioned in the parent comment.

          However, there are many other severe issues, of course. But for hobbyist and professional photography? Mitigable.

          I can see a problem with 100x the current deployment, but the "other severe issues" kick in long before that, anyways.

  • uv-depression

    yesterday at 6:11 PM

    (1) Considering there are now multiple companies planning to launch their own fleets of tens of thousands, satellites need replacing, etc, even if this was completely accurate, this will be a continuous and ongoing issue as it has been for years.

    (2) The standards for astrophotography and for professional astronomical measurements are somewhat different! Also, I think you meant median stacking; mean stacking doesn't handle outliers as well.

    (3) Whataboutism. Besides, you'd get no argument from me about replacing the majority of air travel with high speed rail, even without considering lights.

    I agree that city light pollution is probably the bigger problem, especially for the amateur/cultural angle, but these are two symptoms of the general cause of our economic system not valuing the sky (or the environment generally).

    • qurren

      yesterday at 6:18 PM

      Some good points. However:

      > replacing the majority of air travel with high speed rail

      I absolutely LOVE high speed rail, but I will note that it is correlated with far more light pollution than air traffic. I say correlated because typically high speed rail is routed through high-density population centers, but if there aren't population centers, you'll have to have plans to create them in order to support the rail system itself.

      Basically there is nowhere in the world that has both high speed rail AND suitable for astronomy. If you want to find dark skies in China for example you have to get far away from all the high speed rail areas of the country.

      • adamsb6

        yesterday at 6:56 PM

        My wife's hometown in China used to have two options to reach from Shanghai - high speed rail (top speed ~ 200MPH) that takes about six hours or a roughly one hour flight.

        Rail travel has stops and slowdowns in more populated areas that make it a bit slower than the advertised top speeds.

        • yesterday at 7:00 PM

      • computably

        yesterday at 9:36 PM

        That's a backwards argument. Flights in California between SF and LA will obviously travel a continuous line across California. Yes, the populated areas have light pollution, but that's because they're, y'know, populated areas. HSR itself would add nearly no light pollution outside of the existing population centers, in contrast to flights.

        • qurren

          yesterday at 10:16 PM

          Right, the California HSR route doesn't travel through any really dark sky regions anyway.

          My point was that if you want replace, say, San Francisco <-> Las Vegas with HSR you're going to inevitably have to wreck a chunk of Bortle 1 dark skies in the Sierra or Death Valley.

          Doesn't mean I'm against HSR but it has to be done thoughtfully.

      • oblio

        yesterday at 7:13 PM

        > but if there aren't population centers, you'll have to have plans to create them in order to support the rail system itself.

        This is such a misanthropic point of view.

        Nobody "creates" population centers. People aren't created out of raw clay, they already exist.

        If population centers are "created" it's because people already exist and want to live in a specific place, often time urban.

        And if they wouldn't go to these population centers they wouldn't live in caves in the dark. They would be spread over many more places, yes, creating lower levels of light pollution but lots more of them, covering a lot more land.

        • t-3

          today at 12:01 AM

          Many cities and settlements have been created intentionally rather than as a result of populations organically reproducing on the spot. Colonies, chartered towns/cities/etc, company towns, etc. It's a very common thing throughout history to the present day.

          • oblio

            today at 5:29 AM

            And... the people? Where do they come from? Mars?

            All you're describing is population redistribution, not population creation. Urban centers have very low fertility rates, which actually reduces populations...

• Hilliard_Ohiooo

  yesterday at 4:24 PM

  It's not that big a deal for MOST people. I was on navy ships transiting the Pacific it's as dark as it can get on deck and sure, it's magical and spectacular (especially the NUMBER OF SHOOTING STARS!) but even in the middle of the ocean 99% of my fellow sailors could not have given less of a shit. I'd sit out there for hours and they all though I was a weirdo for it. So, while amazing, most people don't understand or care to understand the enormity of what's going on around them.

  Most people didn't care about dark skys in the first place and still don't.

  • bilekas

    yesterday at 4:55 PM

    Had s similar experience in the saharah desert.. I love all things space and have a teleclscooe I use regularly but seeing it in person and just laying down and watching for hours was another experience.

    I would argue that probably not looking up all the time at night with predators around was an evolutionary trait though! (Semi joking)

  • pdpi

    yesterday at 7:54 PM

    > Most people didn't care about dark skys in the first place and still don't.

    Most people were never given the opportunity to care.

    • rconti

      yesterday at 10:55 PM

      Very true, but isn't that exactly what the parent is suggesting? That even a ship full of sailors given the opportunity to care, very few do?

      Or are you suggesting that by the time they are in the Navy, it's after the age where one might be most easily encouraged to care?

      • pdpi

        today at 3:01 AM

        Mostly the latter.

        There's another aspect to it, though — parent was in a navy ship, surrounded by sailors. That's a very specific population, in a very specific situation, and it's not necessarily true that that's the right crowd or situation to care (though it baffles me how a sailor at sea might look up at the stars without being in awe of the thought "damn, my predecessors navigated based on those")

  • chickensong

    yesterday at 5:11 PM

    There are a lot of Muggles in the world.

  • retired

    yesterday at 7:14 PM

    In parts of The Netherlands is simple never gets dark due to light pollution. It feels like it is always dawn. Pretty bad for your sleep cycle.

    Some pictures: https://milieufederatie.nl/nieuws/6-op-de-10-nederlanders-wi...

  • dfxm12

    yesterday at 7:04 PM

    Depends how far back we go for "first place". Stars are an interesting intersection of social sciences, hard sciences, and even some woo for a very long time. We must consider their interaction between religion, astronomy and astrology going as far back at least as history lets us.

• throwforfeds

  yesterday at 3:24 PM

  I hadn't been out to a dark sky in years so I went out to a deep part of Joshua Tree (Bortle 2-3) one night not too long ago just to see some stars. Wow, I was not expecting that many Starlinks up there.

  • kccqzy

    yesterday at 3:40 PM

    National parks in California are indeed amazing. One time during a group trip to Death Valley, people were so amazed by the night sky that half decided to sleep outside the tents just to experience falling asleep while looking at the stars.

    • RetroTechie

      yesterday at 6:56 PM

      > people were so amazed by the night sky that half decided to sleep outside the tents just to experience falling asleep while looking at the stars.

      Where I live, it usually impossible due to nights being too cold (okay, you can use sleeping bags/extra blankets etc), clouds, or... mosquitos.

      But when/where it's not: highly recommended! "Spaceship Earth" in progress.

    • Hilliard_Ohiooo

      yesterday at 4:27 PM

      [flagged]

      • msie

        yesterday at 4:30 PM

        Really?

• doix

  yesterday at 4:32 PM

  Today I learned about the Bortle scale. I was completely ignorant about it.

  > If you've never seen truly dark skies, do yourself a favour and go see what they look like during true night

  I think I went from only ever experiencing Bortle 5-6 to Bortle 1 when I visited Merzouga and Erg Chebbi. Blew my mind, made me really appreciate the extent of light pollution almost everywhere else I've been.

  • pdpi

    yesterday at 7:57 PM

    > Today I learned about the Bortle scale

    When I first learned about the "clouds are noticeably brighter than the sky" part of Bortle 5, it was like it flipped a switch in my brain. I can't avoid noticing it now.

• Reason077

  yesterday at 9:50 PM

  Wanaka, in the South Island of New Zealand, still has pretty good views of the night sky. You can see an awful lot more stars than you can from major cities.

  But even here it’s under threat: a recent new retail development on the edge of the town (called “Three Parks”) emits so much light that it illuminates the nearby hills at night. The sad thing is that much of this light seems unnecessary to me: eg a hardware / garden retailer has enormous floodlights to illuminate their inner courtyard constantly at night, even when they’re closed.

  The rest of the town has always been pretty good at minimising light pollution, with soft, modest and well designed street lighting in residential areas. But such considerations have been forgotten completely with the new development. Three Parks emits more light pollution than the rest of the town combined!

• yodsanklai

  yesterday at 11:45 PM

  > It's quite depressing how little society values the night sky,

  Considering how little value we put on far more important things (like the climate or biodiversity), I'm not really surprised.

• adrianN

  yesterday at 3:36 PM

  Putting astronomy on the dark side of the moon would probably work better than putting it into space because you can use some local material for construction.

  • uv-depression

    yesterday at 3:39 PM

    There isn't a single "dark side" of the moon that's always in darkness, the "dark side" of the moon is the side that always faces away from us (poor choice of name). It's fully illuminated during a new moon.

    Lunar regolith would probably be quite damaging to optics. It's nasty stuff. I have seen ideas for building liquid mirror telescopes on the moon, though.

    • toast0

      yesterday at 3:50 PM

      Of course the dark side of the moon is illuminated by the sun at times. But it has minimal human illumination, so that's pretty nice.

      • dylan604

        yesterday at 4:31 PM

        human illumination is nothing compared to the giant fusion reactor that would be lighting it up for 2 weeks at a time. At least on terra firma, you can view the sky nightly.

  • shagie

    yesterday at 3:59 PM

    The far side of the moon would be useful for a radio observatory where one can block the noisy Earth while taking advantage of the ability to construct large collection area dishes (think Arecibo in a crater - https://en.wikipedia.org/wiki/Lunar_Crater_Radio_Telescope )

    As to the dark side of the moon, I would suggest a read of the story "A Walk in the Sun" - https://www.baen.com/Chapters/0671878522/0671878522___1.htm (the dusk terminator moves at about 10 mph (15 kph) at the equator).

  • PaulHoule

    yesterday at 5:21 PM

    In space though you can do extremely lightweight construction because structures don't need to support their weight against gravity unless they are huge enough that tidal forces matter.

    Like O'Neill's research group killed off the plan with the big cylinders because you would construct solar power satellites out of plastic films with vapor deposited metal and semiconductors and these would be light enough to send up from Earth and assemble in space.

  • chasil

    yesterday at 8:56 PM

    I have read elsewhere that spinning mercury would be used as the mirror.

    • shagie

      yesterday at 9:08 PM

      The suggestions that I've seen for astronomy on the far side of the Moon have largely been about radio astronomy rather than optical. The lack of the ionosphere which otherwise blocks and distorts 10 meter and longer radio and using the Moon itself as a shield from the radio noise of Earth makes it more interesting.

      Radio telescopes only need a wire mesh to deploy (rather than polished optical mirrors). https://www.skyatnightmagazine.com/space-science/arecibo-tel... has a view under Arecibo.

      https://www.nasa.gov/general/lunar-crater-radio-telescope-lc...

      ---

      The liquid metal mirror telescopes https://en.wikipedia.org/wiki/Liquid-mirror_telescope are interesting in part because you can get liquid mercury temperatures near room temperature on Earth.

      It's theoretically possible for the moon - https://ui.adsabs.harvard.edu/abs/2007Natur.447..979B/abstra...

          A previously proposed liquid mirror telescope, based upon a spinning liquid metallic alloy, is not appropriate for infrared applications, which will require a liquid below 130K. Here we report the successful coating of an ionic liquid with silver. The surface is smooth and the silver coating is stable on a timescale of months. The underlying ionic liquid does not evaporate in a vacuum and remains liquid down to a temperature of 175K Given that there are ~10^6 simple and ~10^18 ternary ionic liquids, it should be possible to synthesize liquids with even lower melting temperatures.
      

      ... But this seems a bit more speculative. It wouldn't be mercury and requires a yet to be discovered liquid metal that is stable for months at 175 °K.

• wompawoo

  yesterday at 5:56 PM

  Check out southwestern Ontario as well. I've driven through there on my way to Michigan a couple times. It's purple at night. The sky is purple.

• SoftTalker

  yesterday at 5:59 PM

  I would have assumed that most plants need a daily light/dark cycle but maybe not?

  • tredre3

    yesterday at 6:16 PM

    Most fruit crops need 8-12 hours of darkness but it changes depending on which point they're at in their life cycle. 20 hours of light is usually fine during the initial stages, then they require 8-10 hours of darkness to bloom, then back to 18-20 hours of light during the fruit growth.

    (I'm not a botanist or a farmer but I grow greenhouse veggies for fun)

  • NoMoreNicksLeft

    yesterday at 6:02 PM

    The world record holder vegetables are all grown in Alaskan summers, up north... where they get 20+ hours of daylight per day. Dunno, maybe the CAM plants would do bad (pineapples) but just about everything else benefits.

• matkoniecz

  yesterday at 6:21 PM

  > instead of building municipal internet

  Starlink is intended and used as solution for places and uses for which municipal internet is not an option at all

  (is it usable at all as replacement for municipal internet? I would guess that you would overcrowd connection quite quickly)

• micromacrofoot

  yesterday at 4:15 PM

  Humans have been looking at the stars every night for tens of thousands of years and we've essentially occluded the night sky to most in the matter of about 50 years, I don't even think most people know what we've lost anymore.

• anal_reactor

  yesterday at 10:40 PM

  Are there places in EU that are dark and easy to visit?

  • yodsanklai

    yesterday at 11:58 PM

    In the EU, the canary islands are known to have great skies. You check this map https://www.lightpollutionmap.info

    I've been in some place with very dark skies, like Death Valley or Teide in the Canaries (https://www.teidebynight.com/tenerifes-dark-sky-reserves-hav...). It was great, but also not that much better than what I've seen closer to home in French countryside or in the alps. Maybe I didn't get the best conditions though.

• kortilla

  yesterday at 4:02 PM

  > other internet providers dumping tens of thousands of satellites in orbit instead of building municipal internet

  Ah yes, that municipal internet in the Pacific Ocean. The municipal internet in the 1 person per square mile rural area. The municipal internet to mountain villages. The municipal internet running to airplanes. The municipal internet to the Antarctic research stations.

  Tell me you don’t know the point of satellite internet without telling me.

  If you want to make arguments against sat constellations so people can make long exposure photos, go for it. But don’t pretend there are actual viable alternatives to LEO sat internet.

  • wussboy

    yesterday at 5:24 PM

    Maybe it's okay for there to be places on the earth where high sped internet is not available?

  • drdexebtjl

    yesterday at 5:25 PM

    > The municipal internet in the 1 person per square mile rural area.

    Yet that person can receive mail, is within a few miles of a major highway, and is likely connected to or close to the electric grid.

    Infrastructure is expensive. LEO Satellite internet is only cheaper because the environmental cost is not being accounted for.

• bpodgursky

  yesterday at 3:17 PM

  Dude your country is 98% desolate and unsuited to agriculture. If you want night sky go to a cabin literally anywhere in your unending and cold mountains instead of shutting down agriculture in the only marginal spot on the west coast you can grow food.

  • magicalist

    yesterday at 3:22 PM

    > instead of shutting down agriculture in the only marginal spot on the west coast you can grow food.

    Not an expert, but I would think greenhouse light pollution is not necessary for agriculture? It seems like obvious waste (money spent generating light that isn't going to photosynthesis), but I assume it's cheaper not to shield the lights than to shield them, so it's a matter of ROI and requiring people take care of their externalities.

    Is there an economic argument that light shields will make agriculture in that area too expensive?

    • bpodgursky

      yesterday at 3:33 PM

      I mean it's not easy to have greenhouse walls that let sunlight in but don't let grow light out. You can direct the light but you are going to have loss.

      • rrr_oh_man

        yesterday at 3:56 PM

        Yeah, let's not inconvenience companies.

        (FYI, it's a solved problem: https://de.made-in-china.com/co_zenong/product_Agriculture-P...)

      • wizzwizz4

        yesterday at 3:51 PM

        Sunlight and grow light generally happen at different times.

  • eliaspro

    yesterday at 3:54 PM

    This is not only about being able to see a nice night sky (although I admit I love seeing one), it's a very much more fundamental issue.

    Light pollution has dramatic negative consequences for wildlife and thereby our ecosystem we so heavily depend upon.

    • bpodgursky

      yesterday at 3:57 PM

      Yes it has negative consequences for wildlife, which is why it is FAR BETTER FOR THE ENVIRONMENT to put all the agriculture in one place at high efficiency rather than spread farmland out over otherwise virgin wilderness.

      Would you rather have 2x the wilderness 80% degraded or 1x the wilderness 90% degraded? Unless your plan is to decide who starves to death, it's far better to have greenhouses where we already have farms!

      • drdexebtjl

        yesterday at 5:08 PM

        Stop with the false dichotomies. I would rather have no wilderness 90% degraded at all. There are better alternatives than spreading out the farmland. Like better greenhouses that don’t blast grow lights all over the night sky. We have the technology, it’s just cheaper to destroy the environment.

      • eliaspro

        yesterday at 4:25 PM

        OK, looks like I misunderstood what you were trying to say.

        Therefore I fully agree with you!

  • uv-depression

    yesterday at 3:45 PM

    I can't just casually hop up to the Yukon for an evening of astronomy. It's about a thirty hour drive. Even relatively small towns have exurbs now because of our terrible city planning, so light pollution extends shockingly far. Alberta's probably the worst, almost the entire province (about the same land area as Texas) has light pollution.

    > instead of shutting down agriculture in the only marginal spot on the west coast you can grow food.

    The Okanagan will be shocked to hear they can't do agriculture! Perhaps we could just turn off the greenhouse lights for a couple hours, or install retractable shields/mirorrs on top of the greenhouses.

    • bpodgursky

      yesterday at 3:59 PM

      What are you on about? Literally drive north a bit towards Whistler, you can get out of the light pollution in an hour or two

      lightpollutionmap.info/#zoom=8.01&lat=49.6027&lon=-122.7672&state=eyJiYXNlbWFwIjoiTGF5ZXJCaW5nUm9hZCIsIm92ZXJsYXkiOiJzYl8yMDI1Iiwib3ZlcmxheWNvbG9yIjpmYWxzZSwib3ZlcmxheW9wYWNpdHkiOiI2MCIsImZlYXR1cmVzb3BhY2l0eSI6Ijg1In0=

      • uv-depression

        yesterday at 6:01 PM

        Have you never been there? This light pollution map wildly underestimates light pollution outside of cities. I can tell you from experience you're not getting nearly 22 mpsas skies anywhere near Pemberton.

  • drdexebtjl

    yesterday at 3:27 PM

    The entire world’s agriculture “shut down” at night before we decided we want every crop to be available everywhere year-round.

    Just install light shields.

    • bpodgursky

      yesterday at 3:34 PM

      Yes we also had a population of 50 million and 10% of them starved to death every time a volcano burped, they were great times.

      • ToucanLoucan

        yesterday at 4:12 PM

        And 9 million starve to death annually because it isn't profitable to feed them, what's your point?

        • bit-anarchist

          today at 2:25 AM

          The point is that we don't need to increase 0.11% back to 10%. Specially when the base numbers have significantly increased.

  • micromacrofoot

    yesterday at 4:16 PM

    or you know, just adjust the lights a little

  • curioussam

    yesterday at 5:45 PM

    [flagged]

• everdrive

  yesterday at 3:24 PM

  >It's quite depressing how little society values the night sky, something that's been an important part of every human culture for longer than recorded history.

  But what if someone were uncomfortable briefly? Did you ever consider that? Technology exists to infantilize us while slowly ruining everything that makes us human. Shame on you for attempting to interrupt human progress.

  • yesterday at 5:53 PM

Where I live, we have a small park, 500m away. You need to walk through it if you want to get to the city center from the small neighborhood we live in. To protect the wildlife, the lighting system has presence sensors, so as you walk or bicycle through the park, the way/street lighting turns on, you can walk, and just after you, it turns dark again. Really cool, especially the first time I went through it in the middle of the night.

• fhdkweig

  yesterday at 2:52 PM

  Those things drive me nuts. There is a walking path that I frequent, and I can't use it at night because they are spaced every 20-30 feet. When I am not under them, they are off and my eyes adjust to the darkness and as I pass under one it flips to full daytime brightness and blinds me. As soon as I walk away from it, everything goes dark again, but my eyes had adjusted to the daytime brightness of the lamps. And I know that in 30 feet, I have to do it again, for the next couple of miles.

  • Loic

    yesterday at 4:00 PM

    The timing and brightness is well adjusted, it feels natural, like a friendly ghost taking care of you.

    • fch42

      yesterday at 8:53 PM

      unfortunately they never are. Brightness-adjusted, that is. Everyone installing lighting fixtures these days believes they must be daylight-level bright. The only ghosts you see are afterimages if you happen to look straight at the streetlamp ...

      (I find it odd; dark-adapted eyes see a lot, including movement in shadows or low-contrast obstacles - after all, our bodies know how to see well at moonlight levels of illumination. Why are we so keen to kill this ability?)

    • RetroTechie

      yesterday at 7:10 PM

      Your Park May Vary (YPMV).

• trollbridge

  yesterday at 3:08 PM

  Wouldn't it be more reasonable to just expect people who want to walk places in the dead of night to wear a headlamp? They're cheap, easy to recharge, and can be adjusted for various brightness levels.

  • amiga386

    yesterday at 3:30 PM

    The problem is not just with people who want to walk places, but people who want to mug/murder/rape those that do.

    As an example, in the UK, councils are expected to light commonly-traveled paths, both so path users can see where they're going, and to reduce crime. Unlit paths in city parks are still traversed, and are often a haven for crime.

    "Dead of night" isn't the right image. 5PM in winter with clouds (as is typical in the UK) has roughly the same level of natural light as 2AM. People are still coming home from work in conditions where natural light is low enough to lead to accidents and crime.

    • culi

      yesterday at 10:18 PM

      I hesitate to even engage in a conversation about organizing our entire infrastructure/society over such a rare incident, but I'll bite.

      Powerful lights are known to actually increase safety risks. Our nightvision is reduced and the shadows of the lights are the most dangerous parts. Perhaps more dangerous than no light at all.

      Once city (I can't recall which) had a really cool solution to this where they installed string lights. Lots of small, dim lights don't negatively impact your nightvision, keep the path pretty visible, and don't cause too much light pollution

    • adrianN

      yesterday at 3:38 PM

      TFA claims that lights don’t reduce crime, but I‘d like to see the exact meaning of that statistic (eg dark places are less frequented hence less crime?).

      • amiga386

        yesterday at 5:59 PM

        TFA doesn't even claim that. TFA links to an advocacy website trying to convince authorities to put out less light pollution. It claims improved lighting (presumably brighter) doesn't reduce crime, and it claims a reduction (but not elimination) of lighting doesn't increase crime.

        I would say that going from no lighting at all, to some lighting, on urban paths, improves safety (not tripping over unexpected obstacles) and reduces crime (presuming there was any crime while it was unlit). The article doesn't refute that. I would suggest that if a major city decided to eliminate all street lighting, it would be absolute chaos.

        • teamonkey

          yesterday at 8:37 PM

          Nobody is trying to remove all street lighting. There are plenty of practical suggestions on here and in that document about how things can be improved without reducing safety.

      • PaulHoule

        yesterday at 5:22 PM

        Lights help criminals see what they are doing.

    • today at 12:18 AM

    • naravara

      yesterday at 3:43 PM

      > The problem is not just with people who want to walk places, but people who want to mug/murder/rape those that do.

      This is a completely irrational (though commonplace) fear. Criminals aren’t hiding out in bushes in desolate parks to mug or rape random people. Muggings most commonly happen in side paths off of busy high streets because criminals, being people, like to hang out in stimulating places where they won’t get bored. They’re not going to be donning ghillie suits and lying patiently in wait for however long in uncomfortable brush for a hapless victim to cross their path. The muggings are crimes of opportunity. Rapists are most commonly somewhat trusted friends or acquaintances who have access to people when they’re in vulnerable states in private, protected spots.

      Thinking parks and parking lots need to be lit up like Christmas to deter crime is just a veneer of rationalization to cope with the standard childhood fear of the dark. It is not backed by data or evidence. The actual main public safety concerns when it’s dark out are trip-and-fall hazards or collisions with or vehicles who can’t react fast enough when things pop out at them, not muggers and rapists. Having the nighttime environment overly lit actually makes shadows starker and blows out people’s night-vision so they can’t find things. If anything, it makes the edge case where Sam Fischer is hiding in the bushes more dangerous rather than less.

      • amiga386

        today at 12:33 AM

        > desolate parks

        Criminals hide out in the dark parts of urban parks, mere minutes away from well-lit, more populated areas of the city. They're not going to get bored. Victims walk through the parks and get jumped, occasionally dragged off into the darker parts.

        To give a example: The Meadows in Edinburgh: https://www.openstreetmap.org/way/233760765

        A park between the university and student accomodation. Very popular with students going home at night. Apart from a few lit paths, entirely dark. Most paths are lined with trees, like so: https://www.edinburghnews.scotsman.com/webimg/b25lY21zOjAxYz...

        Here's a small sample of incidents. There are genuinely criminals who hang about in the dark parts of this park, late at night, in order to attack victims. They don't have to wear ghille suits, they need only stand behind the trees.

        - 2011: https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-1... "Two men who grabbed a young woman before one sexually assaulted her in an Edinburgh park are being sought by police. The 19-year-old woman was walking through the Meadows at 03:30 on Tuesday when she was attacked at a spot north of Melville Drive."

        - 2011: https://www.scotsman.com/news/charges-over-sex-assaults-in-m... "Lothian and Borders Police issued an open letter to students and residents in response to the incidents, advising them not to walk alone in the Meadows at night"

        - 2012: https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-2... "The 30-year-old was walking through Middle Meadow Walk at about 22:30 when two men approached him. One of the men punched the victim in the face, knocked him to the ground and continued assaulting him before taking his personal belongings."

        - 2014: https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-2... "The 25-year-old was walking near the tennis courts at the east end of the park at about 04:30 on Saturday when he was approached by two men. After asking the man for money, the two attackers punched him several times, causing minor facial injuries, and also tried to steal his watch."

        - 2014: https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-3... "Steven Davidson, 24, attacked the 19-year old as she made her way home through the Meadows in November 2014. [...] Davidson ran up and grabbed her from behind. [...] The woman had been making her way home just before 07:00 [...] she passed out and came round to find him lying on top of her. He then raped her."

        - 2016: https://archive.news.stv.tv/east-central/1374940-three-assau... "Police are investigating after three assaults were carried out on the Meadows in Edinburgh within 15 minutes of each other. In each of the incidents, which took place between 3.10am and 3.25am on Sunday, the attackers robbed or attempted to rob the victims of cash or possessions."

        - 2020: https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-5... "The attack on the 37-year-old took place on The Meadows at about 23:15 on Saturday"

        - 2023: https://www.edinburghlive.co.uk/news/edinburgh-news/edinburg... "The incident took place at around 4am on Sunday, January 29."

        I'm not saying we should floodlight the park. What has helped most is regular police patrols of the park. But I'd be lying if I said the criminals don't hang out in the dark parts of this park, waiting for victims. They do.

      • RetroTechie

        yesterday at 7:38 PM

        To add a small datapoint in support of the above: I happen to spend many nights in rural areas. Some with towns & nearest neighbours far enough away that nights are truly dark.

        Those nights are the safest in my experience. Simply because no thief or mugger would bother to venture out into the middle of nowhere, in the off-chance there's something to be had there. That's assuming they'd even know someone/something to be there! And even if they would, chances are I'd be quickly aware of their presence, or some geese/other birds would announce their presence.

        TLDR; Be careful in areas with lots of people, or on the edge of such areas. Places that lack people tend to be safe.

  • wongarsu

    yesterday at 3:17 PM

    People associate a lack of lighting with crime

    I vaguely remember that studies showed that lack of streetlights does not create crime, but the crime that happens anyways prefers badly lit areas. But from a pedestrian's perspective that's not much relief, you'd still avoid those areas. Which is not what a city planner has in mind for a park

    • stouset

      yesterday at 8:12 PM

      Also part of the issue is that lighting at night creates enormous contrast between dark areas. Even darkness is something our eyes are well-adapted to, and we can see surprisingly well with even a little moonlight. We struggle with alternating bright/dark areas.

  • ninalanyon

    yesterday at 5:07 PM

    No. Unless you expect everyone to always have those things you will need the street lights anyway so why not make them smart and efficient. This especially applies in northern latitudes where it is dark in the evening even before people leave work.

  • fhdkweig

    yesterday at 3:17 PM

    I would consider that ideal, but there would always be the fear of a potential negligence lawsuit if someone got hurt or crimed, so the government considers them necessary.

• redlewel

  yesterday at 5:15 PM

  Would prefer very dim or red lighting. Also preserves your night vision

• snarf21

  yesterday at 5:04 PM

  Serious question: Wouldn't it be better to just have them always be on with red light that is much less disruptive to wildlife?

  • adrian_b

    yesterday at 7:39 PM

    The sodium lamps that were ubiquitous for outdoor lighting before LEDs were quite good from this point of view.

    Amber LEDs could provide a similar experience.

• vel0city

  yesterday at 2:58 PM

  If it gets used a good bit, I wonder if the on/off cycles are even more impactful to the local wildlife than constant but more optimized lighting was in place.

  I know if I was trying to sleep a constant source of light is easier to get used to than a randomly flashing source of light. And for nocturnal animals I'd imagine randomly losing the cover of darkness from time to time is probably a lot more stressful than just avoiding the brighter areas.

  I'd be interested in seeing data. I really wonder which is better.

> “… gives the illusion, without the reality, of safety”

This actually isn’t true. Having done physical security work before, a weird fact is that one of the best physical deterrents is lighting; even over CCTV.

I don’t say that to take away from this, this is great work and I’d love to see the lighting toned down for multiple reasons. However, this should be framed as a security tradeoff not an outright win.

Source: The Impact and Policy Relevance of Street Lighting for Crime Prevention: A Systematic Review Based on a Half-Century of Evaluation Research (https://www.crimrxiv.com/pub/wl9zqxga/release/1)

• LanceH

  today at 3:23 AM

  Driving down the road past a police cruiser on the side with it's lights on is far from safe. The escalation of brightness makes them visible beyond anything else...like the road.

We need much better engineering standards if we are going to fix night lighting. A simplistic lux-on-the-ground measure combined with cost minimization produces a few lights, with bare bulbs, up hight, with brutal intensity. These are all things that produce glare directly on the eyeball.

You need much less light on the ground if the eyeball itself has no direct line to the hottest part of the lights. Instead, the night-blindness caused by excessive bare lighting is "fixed" by adding more fill lights for the shadows caused by the first lights. Classic addictive behaviour.

• projektfu

  yesterday at 7:51 PM

  I believe that is what TFA is about.

I once lived in a city that had replaced street lights that cast light in a circle with modernised ones that cast a sharply delimited rectangle of light on the road, and didn't waste light in other directions.

The thing was, the roads of this city were arranged as a footpath, then a grassed area with trees, then the lights, then the roadway. Only after the city had rolled out thousands of these lights did someone notice the footpaths were now much darker. And also the footpaths were quite uneven, due to the trees' roots - a problem the lights had previously been keeping under control.

It's now common, in winter, to see groups jogging on the road.

• wongarsu

  yesterday at 3:18 PM

  Planners forgetting that pedestrians exist is sadly a common occurrence

• Rotundo

  yesterday at 3:08 PM

  Over here, joggers are frequently wearing headlamps to illuminate their way. Often combined with a light on their back. They can see and can be seen, which is safe.

  • michaelt

    yesterday at 4:09 PM

    There are some fine products on the market compared to a few decades ago, yes. I particularly like the fact rechargeable lights are always at full brightness.

    Alas when running in a group, the runner in front of you can not just obstruct your line of sight of the pavement, but also the light of your torch. His retroreflective vest becomes the brightest thing in your view. And he's not happy either; backlit by your torch, he casts a shadow forwards and the road ahead is illuminated everywhere except where he's about to step. And of course the tree-lined pavement, while very beautiful and shaded in the summer, isn't very wide. So you can't always run beside the guy.

    My personal 'solution' is not to run fast enough to keep up with the guy ahead of me, giving me a clear view. But you don't win medals with my attitude.

• Finnucane

  yesterday at 4:03 PM

  Get rid of cars and they'd take down all the lights.

I'm surprised it didn't suggest using red LEDs without phosphorescence, which has several advantages:

1. Red light preserves your dark adaptation

2. It doesn't have as much of an impact on your circadian rythm

3. Not using phosphorescence can increase the lifetime of the light, since you don't have to worry about the coating degrading

4. Red light is less energetic, so could potentially use less power.

5. Since an LED without phosphorescence is a single wavelength, telescopes (and binoculars) can use a narrow band filter to filter out the light pollution, without blocking most of the light from celestial objects.

> Thorp notes that modern CCTV cameras are “pretty great” even at low-light levels, while harsh light makes it hard for both human eyes and digital sensors to see.

That’s a weird thing to include. That sounds like an argument _for_ more aggressive lights. I didn’t expect to see a “think of the surveillance system”

• swiftcoder

  yesterday at 2:33 PM

  > That’s a weird thing to include. That sounds like an argument _for_ more aggressive lights. I didn’t expect to see a “think of the surveillance system”

  One of the biggest excuses for ultra-bright streetlights is crime prevention (usually shortly followed by CCTV). I'm not really sure why we continue to indulge that point of view, but if one is indulging it...

  • rznicolet

    yesterday at 2:44 PM

    It's even funnier that, at least around here, one of the biggest crime problems is people stealing copper wiring... from streetlights...

  • Jblx2

    yesterday at 7:57 PM

    I know we can be all righteous and intellectual on HN. But the article pretty much glosses over the large number of people who are afraid of the dark. Not afraid of crime in the dark. Actual adults who are apparently having a visceral reaction to the dark. What percentage of people is this? What percentage of those would adapt in a positive manner?

    • swiftcoder

      today at 6:04 AM

      Those people can carry around a cheap LED lamp if it so pleases them...

  • trollbridge

    yesterday at 3:10 PM

    The "lights=safety" nonsense shows no sign of coming to an end. Many private residences also install eye-searing levels of lighting outside that they just leave on all night, which is much cheaper to do now thanks to LED technology. There's really no reason for doing it. The idea it deters crime is a long-standing myth (someone analogous to the idea CCTVs deter crime).

• pjl0

  yesterday at 7:57 PM

  If your goal is to reduce light pollution, addressing/deflecting the concerns of the surveillance state is probably more likely to get you to that goal than ignoring the concerns entirely or tying yourself to the omnicause

• mghackerlady

  yesterday at 2:58 PM

  Even then, couldn't you just use IR cameras with IR lights for illumination. I'm sure that comes with it's own set of issues, but strictly speaking is better for maximising surveillance while minimising human impact

• WarmWash

  yesterday at 2:33 PM

  Their prime audience for change are governments...

Our city recently went on a crusade on replacing all of the high pressure sodium bulbs with LEDs, with the justifications of driving safety and energy savings. I agree that these are important, but the LED bulbs they chose are actively hostile to homes and pedestrians. They are blinding. You can't look at them. I have one outside our house in the main viewing angle and we need to close our shades as soon as they are turned on.

• pelotron

  yesterday at 5:00 PM

  Back in the day the city installed a new streetlight that blinded anyone sitting on the front porch of my grandparents' house, which they liked to do in the evening. So Granddad got out a painter's pole and rolled some white paint onto the side that faced his house. Problem solved and no one ever said anything.

• culi

  yesterday at 10:21 PM

  :rock: + :slingshot:

I think people focus far too much on the temperature of LED street lights and rarely on the CRI. The night will still feel odd and "soulless" even with 2700k LED street lamps so long as they're still the absolute worst CRI.

Dare I argue even I would choose 6500k LED street lights with decent CRI over poor CRI 2700K LED lamps any day.

• tredre3

  yesterday at 6:28 PM

  > The night will still feel odd and "soulless" even with 2700k LED street lamps so long as they're still the absolute worst CRI.

  What makes you say that the CRI causes the lack of soul? I'm not saying that you're wrong, but given that CRI is objectively better than it ever was now, why?

  The sodium lamps we used previously had a CRI of 25-35. The absolute worst white LEDs we have have a CRI of at least 60.

• krackers

  yesterday at 7:17 PM

  Sodium vapor lamps didn't exactly have high CRI either

I've started doing this in my home. All lights are smart LEDs. At 8pm, they shift warm, 80%. From 9pm-10pm, they go from 80% to 0%. At 7am, they start going from 0% to 100% cool (I work from home and it helps with focus).

Having my environment reflect the patterns of nature has really been a nice change.

• Marsymars

  yesterday at 3:51 PM

  I do something similar with my exterior lights - at sunset my lights come on at ~1% at 2000K. If they detect motion (in my driveway or back deck) they go up to 100% at 2700K. At sunrise they turn off.

  Note that bulbs exist that automatically warm as they dim - so in my case the switches are smart, but the bulbs themselves are all dumb.

  • redmaple892

    yesterday at 4:27 PM

    What type of system are you using outdoors?

    • Marsymars

      yesterday at 4:55 PM

      * Automation: Home Assistant

      * Smart switches: Lutron Caseta. (With the dimmer for ELV lighting so I can use the middle button for specific brightness/warmth levels.)

      * Outdoor bulbs: Philips warm glow bulbs. (2200K-2700K warm dimming, 95 CRI - these ramp from 0% at 2200K to 100% at 2700K)

      * Outdoor recessed lights: Globe Electric DuoBright LEDs (2000K-5000K warm dimming, 96 CRI - these ramp from 0% at 2000K to full lumens at 3000K at 80% the dimmer, but then will continue to ramp from 3000K to 5000K at full lumens if the dimmer is turned up.)

      * Motion sensors: Philips Hue Outdoor sensors.

      Non-smart bulb availability is kinda weird, my specific bulbs may be discontinued or unavailable outside of Canada, but I'd expect local alternatives to be available.

      • redmaple892

        yesterday at 5:05 PM

        Awesome thank you for sharing. I recently bought a very basic low-voltage system just to have something in the garden but would like to upgrade exterior fixtures at some point and your system seems nice.

All the car headlights for new cars in Canada are LED and it makes driving at night painful and dangerous. So many times I’ve been nearby blinded by them and I can’t see anything ahead. And it actually physically causes me pain.

• yonatan8070

  yesterday at 5:46 PM

  But is that the fault of the LED? That sounds like the fault of whoever calibrated the LEDs' brightness and directionality.

  If the beams were the right brightness and pointed downwards, we wouldn't be having this issue.

  • throwaway173738

    yesterday at 9:47 PM

    There will always be situations where you’ll be under the cut point of a low beam. If there’s a small incline then a flat intersection the drivers opposite the incline get the fill low beam. It’s part of what makes HID lighting dangerous to pedestrians. It obscures the vision of oncoming drivers turning left or right. Also if an automatic headlight system doesn’t react to turn the high beams off it will blind people.

  • GrinningFool

    yesterday at 7:02 PM

    Not really. When incandescent headlights are mis-aimed, it is generally not nearly as blinding or painful [for standard car headlights]. Mis-aims happen - it shouldn't be a risk to other drivers when they do.

• bahmboo

  yesterday at 11:05 PM

  I'm optimistic this won't be a problem in 10-20 years (I agree that's a long time). We have the technology in matrix headlights that were banned in the US and basically in Canada up until a few years ago. I expect to see kits on Amazon in a few years for retrofits. Since they need a camera and some brains they will likely start at many hundreds of dollars but that should come down.

I am generally for a light government touch, but I think excessive light and sound are forms of pollution and should be generally regulated in a not-overly burdensome way (give people fix it tickets etc). Policing excessive light, and excessive blue light, would be pretty trivial. And I think cameras that automatically ticket loud vehicles would be amazing.

I read through most of the article but didn't see motion sensors mentioned. A lot of suburban streetlights are lighting up empty streets at night. With a combination of motion sensing and LEDs, lighting could follow pedestrians. Cars really don't need street lights in most cases but even then, in higher risk areas, motion sensors could turn on streetlights just as long as needed.

• wffurr

  today at 1:11 AM

  A motion sensor activated light unpredictably turning off and on on my street would be worse than the steady street lamps we have now. It would be even more distracting and annoying.

> The use of solid-state technology gives the lights an extraordinary life-span, often measured in decades rather than years.

I have found this not to be the case. They seem to last several years, but not an amazing period of time. Also, the ones that were installed in my home are quite expensive, something like $45 per can (the whole thing must be replaced), and the price to install is $30 per can because the company changed their plug design in the last 5 years. So I end up spending $75 for each light, which is roughly $10 per year per light (per light-year?). That doesn't strike me as a great value, especially because I can't change the lights myself due to the wiring/plug situation. Maybe that piece won't apply in future years, but it's still a lot even if it's just $45 for the darn can.

• ssl-3

  yesterday at 9:47 PM

  At home, my solution to that is to use lighting fixtures have Edison sockets inside for a bulb to screw into, just like they always used to.

  The fixtures last forever, and may have already been there for half a century. It doesn't need changed.

  The bulb lasts as long as it lasts, but is easily replaced. It can be dumb, or it can be smart. It can be changed for different color temperature or CRI or protocol or efficiency rating or whatever.

• aidenn0

  yesterday at 7:00 PM

  Yes, I was wondering if they really last longer than sodium-vapor lamps, which last about 5 years at a 50% duty cycle.

  • apparent

    yesterday at 7:07 PM

    I imagine they last longer than some other types, but it hasn't been an order-of-magnitude difference that was advertised. Also the cost/hassle is much more than expected.

    We've put some smart LED bulbs into some fixtures, and those have been fine. But they've only been in for a few years, so we don't yet know their lifespan.

• adrian_b

  yesterday at 7:51 PM

  I have seen a lot of complaints about LED lamps with a short life, usually caused by defects in their integrated power supplies, typically arising from bad cooling.

  On the other hand, I have more than a dozen LED lamps that have been continuously used for more than ten years and none of them has failed yet. They are mounted in classic Edison fixtures for incandescent lamps and they were made by Philips, but at the time when they were bought they were one of their better models, and having a 4000 K color temperature, i.e. very slightly yellowish, but not noticeably yellow, like the lamps with a color temperature less than 3000 K, which try to imitate incandescent lamps.

I am Dutch but live in Canada, and when I visit family in The Netherlands, I always notice how much darker it gets during the night, even when my family lives in a larger town than me.

For those in the northeastern US, I highly recommend a visit to Mesawisla in Maine, it's a national dark sky park with cabins and an AMC lodge that provides fantastic food.

• chrisweekly

  yesterday at 11:27 PM

  argh, typo, too late to edit

  Medawisla

  https://www.outdoors.org/destinations/maine/medawisla-lodge/

I wondered if a city-wide synchronised Pulse-Width-Modulation of LED lights could allow astrophotography (or even naked-eye astronomy) to be possible again, with a filter synchronised to the off-cycle.

• Rotundo

  yesterday at 3:13 PM

  Using PWM to dim lights should be banned wholesale. Many people, me included, get crazy headaches from the worst lights and mild discomfort from the best ones. It's also completely unnecessary as non-flickering bulbs do exist and are readily available for the same price.

  • weberer

    yesterday at 3:37 PM

    Those are probably 50-60 hz flickering from the mains frequency rather than PWM. (Or 100-120 hz due to the rectifier). Actual PWM ICs drive LEDs over 10,000 hz, which is truly imperceptible to the human eye.

    • tredre3

      yesterday at 6:43 PM

      Surely a PWM of 10,000Hz wouldn't allow for night sky photography. With full exposure it can already take minutes of hours to take a night sky a photo.

      And it's usually recognized that 1,000hz is the bare minimum to spare sensitive individuals from symptoms, with 2,500 usually used for safety margin. Then you have to account for some jitter in the synchronized network so you're looking at at best a 1/5,000 exposure.

      Is that sufficient to be worth the trouble?

      • ireflect

        today at 5:08 AM

        You can still get a long exposure by accumulating many 1/5,000 exposure shots together. Just like a regular long exposure, this will still cancel out random noise and improve SNR, and also still has the tradeoff of motion blur. This kind of accumulation is commonly done in photography-adjacent technologies like spectroscopy.

        Regardless, I agree with your larger point that the proposed system would be entirely impractical!

    • tzs

      yesterday at 8:55 PM

      > Actual PWM ICs drive LEDs over 10,000 hz, which is truly imperceptible to the human eye.

      But then you can get capacitors or inductors emitting a very annoying 10 kHz whine. There are higher end LEDs for various commercial uses that use PWM at over 20 kHz to avoid that.

    • yesterday at 5:04 PM

  • esikich

    yesterday at 11:45 PM

    That's unrectified LEDs flashing at mains frequency, not PWM.

• coryrc

  today at 3:37 AM

  No, because the phosphors glow for much longer than human persistence of vision.

• fhdkweig

  yesterday at 2:59 PM

  Los Angeles has the Griffith Observatory. To allow the city to have street lighting while not interfering with the observatory, the lights are sodium vapor lights that emit a specific wavelength that the observatory can filter out. Since LEDs also use specific wavelengths, this could have been done.

  I was disappointed that the article didn't mention this, especially because they did mention sodium, but only as a pretty color.

  • OkayPhysicist

    yesterday at 4:07 PM

    I quite like the 2 wavelength light that sodium lamps give out. When I was in school, my university gradually went from all sodium to all LED, and it was definitely a loss. The complete loss of hue, combined with the soft buzz of a dying sodium lamp had a certain otherworldly feel to it. I found it quite relaxing.

The lights are not just impacting space but ecosystems switching to LEDs can save ecosystems too.

We have been working hard on this in New Zealand, in the South Island

We started in Tekapo (https://www.darkskyproject.co.nz/) which being rural with a very low population density, and mountainous and with existing observatories to protect

In recent years the effort has moved into the cities (https://www.dunedin.govt.nz/council/policies,-plans-and-stra...)

Interestingly people who live on hills, overlooking the suburbs, complain the lovely view of the sparkling streets was going dark!

But not only does it preserve the stars it is much cheaper, so not going back

Point is: this can be done and the nighttime rewards and financial rewards make it worthwhile

Since I picked up a Pixel phone, I've been doing some amateur astrophotgraphy, and mostly from the balcony at my apartment.

However, I live in a built-up urban area, and my home is absurdly light-polluted. Like, you wouldn't believe it! The parking lot here is ringed with flood lamps that are aimed into our windows. So every hundred feet or so, there is a bright-as-the-Sun lamp in my face, and with a clear view, I can spot about five of them.

So from my balcony, my only hope to get some darkness for the camera is to get into shadows. The railings provide a band of shadows that I can use to block the floods from getting on my lens. So if I position the camera juuust right, it kinda feels darker than it is, and I've got to say I've captured some impressive starfields, down to magnitude 9 or dimmer, including bodies such as Uranus and 4 Vesta.

I also found that the ballcourts in the rear of my property provide this unique "cave" situation with lots of shadows where I can capture the sky directly overhead, and to the west. This is how I photographed the last lunar eclipse.

Now that's my view to the west and 225° (due southwest). If I go on the other side of the property to look east, I've got the same crazy situation with flood lamps, but there's basically no way to hide in shadows. I literally cannot photograph anything rising in the east if it is dimmer than the Moon.

So really, my astronomy hobby mostly consists of doing some great editing, curation, identification, and mostly simulation from the comfort of the air-conditioned indoors. I enjoy what sightings I can while outdoors, and that's included some meteors, the ISS, Tiangong, and a few Vandenberg launches. We're still hanging in there!

I read the entire article and am really glad the author took time to write this down and for OP for posting. I am so tired of poor (mostly outdoor) but also indoor lighting. I have felt crazy feeling that the so-called "better" LED's in parks and on paths have felt like less lighting. Unfortunately I think changing things (in the US) often requires proving harm...science and aesthetics don't seem to matter much at all many place.

The writing style frustrated me immensely.

tl;dr: Cheap cool-white LEDs cut energy but worsened light pollution; warmer, dynamically dimmable LED fixtures/infra fix it but lower costs tend to win.

• trollbridge

  yesterday at 3:12 PM

  Isn't it standard journalism? Instead of just giving us the conclusion we're supposed to think, they interview various people in the field and quote what those people think, and then let us draw our own conclusions.

  • lysace

    yesterday at 3:14 PM

    No, this is engagement-maxxing style journalism. Complete with the clickbait headline. It also spends almost no time on why the cheaper-but-dumber options win.

    (Everything is relative. I expect more from IEEE than the NYP or the Daily Mail, as extreme examples.)

• micromacrofoot

  yesterday at 4:17 PM

  depending on who you ask the cold lighting also magically stops crime

I would 100% rather have a truly bright and lively city at night than a visible night sky. More than half the year is in the winter ffs!

I hate outdoor LED lights so much, I won't be surprised if a couple decades or centuries from now we discover that these things have been doing permanent damage to people's eyes. It's getting harder and more unpleasant to walk at night, I can't see and my eyes legitimately hurt every couple of minutes.

• BLKNSLVR

  yesterday at 2:59 PM

  Does this trigger you: Modern car LED headlights

  There doesn't appear to be any standard being followed (anymore?) on brightness or angle or height (or shape). A selection of them are easy to confuse with high beams. Makes driving at night in the rain some kind of epilepsy inducing overwhelm of lights and reflections and lens flare coming from everywhere, reminiscent of the cyberpunk aesthetic.

  • trollbridge

    yesterday at 3:12 PM

    In the U.S., the DOT sets standards, but they only apply to new vehicles sold. Aftermarket lights can be just about anything. (Some are labelled "not for highway use", as if that prevents them from being used on public roadways.)

    Certain types of people seem to think they should install really, really bright LED lights in their car and then aim them right at other driver's eyes. I believe this comes from a mindset where one is unable to put one's self in another person's aspect, or where one simply doesn't care about others.

    • dec0dedab0de

      yesterday at 3:16 PM

      I hated these so much until I got a car with a tinted rear windshield, and a self-dimming mirror.

      • trollbridge

        yesterday at 6:12 PM

        Or get the orange driving glasses.

  • alt227

    yesterday at 3:06 PM

    At least in the UK this is being looked into by a government review.

    Whether that will amount to anything or not remains to be seen, but at least the issue is being taken seriously.

    https://www.bbc.co.uk/news/articles/cn971jlpvvro

• BoxOfRain

  yesterday at 3:49 PM

  I miss the night looking like night, the ultra-harsh white LEDs used in street lights are trying to mimic daylight which is the last thing you want to do at night in my opinion. The old sodium lights might have had unnatural colour rendering (or in the case of low-pressure entirely monochromatic amber) but this was a small price to pay for warm outdoor lighting. There's no reason SOX and SON bulbs can't be approximated more efficiently with LEDs, we could have the economic benefits of LEDs without the horrible side-effects of cheap and nasty ones.

  I'm not sure where a previously sensible industry decided ultra-harsh daylight bulbs were warranted literally everywhere, in the past harsh white halide bulbs coexisted with sodium ones for decades and there was always guidance on when to use gentle sodium versus harsh halide lights. Apparently everything needs to be as harsh as possible these days, damn the institutional knowledge. I'm not anti-LED but I'm anti-'lots of blue spectral content at night' regardless of the source.

  • adrian_b

    yesterday at 4:20 PM

    I completely agree.

    I am very happy with my indoor LED lamps, but outdoors wherever the sodium-vapor lamps have been replaced I hate their replacements.

    While replacing high-pressure sodium lamps with LEDs brings a somewhat better energy efficiency, the low-pressure sodium lamps already had a similar energy efficiency.