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LEDs’ potential to save our night skies

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Re: LEDs’ potential to save our night skies

#41

Post by adrianN »

amiga386 wrote: post #36
trollbridge wrote: post #19

Earlier quoted context omitted.

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.

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 ty…

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?).

Re: LEDs’ potential to save our night skies

#42

Post by binarymax »

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.

Re: LEDs’ potential to save our night skies

#43

Post by uv-depression »

adrianN wrote: post #39
uv-depression wrote: post #25

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 ma…

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.

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.

Re: LEDs’ potential to save our night skies

#44

Post by kccqzy »

throwforfeds wrote: post #33
uv-depression wrote: post #25

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 ma…

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.

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.

Re: LEDs’ potential to save our night skies

#45

Post by naravara »

amiga386 wrote: post #36
trollbridge wrote: post #19

Earlier quoted context omitted.

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.

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 ty…

> 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.

Re: LEDs’ potential to save our night skies

#46

Post by uv-depression »

bpodgursky wrote: post #29
uv-depression wrote: post #25

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 ma…

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.

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.

Re: LEDs’ potential to save our night skies

#47

Post by BoxOfRain »

SuperNinKenDo wrote: post #9

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.

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.

Re: LEDs’ potential to save our night skies

#48

Post by toast0 »

uv-depression wrote: post #43
adrianN wrote: post #39

Earlier quoted context omitted.

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.

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.

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.

Re: LEDs’ potential to save our night skies

#50

Post by wizzwizz4 »

bpodgursky wrote: post #37
magicalist wrote: post #32

Earlier quoted context omitted.

> 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…

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.

Sunlight and grow light generally happen at different times.
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