Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

LEDs’ potential to save our night skies

spectrum.ieee.org

Post reply on HN
Print view View original

61–70 of 200 posts

Re: LEDs’ potential to save our night skies

#61

Post by OkayPhysicist »

fhdkweig wrote: post #16
theodorethomas wrote: post #11

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.

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 pret…

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.

Re: LEDs’ potential to save our night skies

#62

Post by michaelt »

Rotundo wrote: post #18
michaelt wrote: post #3

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 not…

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.

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.

Re: LEDs’ potential to save our night skies

#63

Post by ToucanLoucan »

bpodgursky wrote: post #38
drdexebtjl wrote: post #35

Earlier quoted context omitted.

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.

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.

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

Re: LEDs’ potential to save our night skies

#65

Post by micromacrofoot »

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…

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.

Re: LEDs’ potential to save our night skies

#66

Post by micromacrofoot »

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.

or you know, just adjust the lights a little

Re: LEDs’ potential to save our night skies

#67

Post by micromacrofoot »

lysace wrote: post #8

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.

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

Re: LEDs’ potential to save our night skies

#68

Post by adrian_b »

BoxOfRain wrote: post #47
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 approximat…

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.

Re: LEDs’ potential to save our night skies

#69

Post by Hilliard_Ohiooo »

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…

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.

Re: LEDs’ potential to save our night skies

#70

Post by eliaspro »

bpodgursky wrote: post #55
eliaspro wrote: post #53

Earlier quoted context omitted.

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.

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…

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

Therefore I fully agree with you!

Post reply on HN