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Simple streetlight hack could protect astronomy from urban light pollution

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Re: Simple streetlight hack could protect astronomy from urban light pollution

#61

Post by amluto »

jcalvinowens wrote: post #35
wruza wrote: post #9

Ah, the good old "human eye can't see N Hz" that will make night lights insufferable for those who happen to see it. My grandma has a couple of lightbulbs in her apartment that annoy nobody except me. I feel like laser-blinded when they are on, no matter where I look. It's blindingly bright and visually dark. Idk if it's flicker frequency or light spectrum tbh, but it's that same "hey you shouldn't see it, cause nobo…

I feel the same way. If I'm sitting still I find I don't care much... but if I'm working with my hands and moving around it drives me crazy and gives me headaches, especially if I'm focusing on something spinning. Just for fun, I replaced the LED dimmer in my garage with a homemade board that has a frequency knob in addition to a duty cycle knob. I've found that the cutoff for bothering me is around 10KHz, which is f…

You should consider talking to the researchers who developed IEEE 1789. 120 Hz is problematic for many people, but 10kHz seems unusual unless you’re a camera.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#62

Post by op00to »

amluto wrote: post #60

No. The article is light on details, but: > A simple device that makes LED lights flicker at a very high frequency that is imperceptible to the human eye > shutter, which needs to be lightweight and agile enough to blink about 150 times per second. Subjecting an entire city to 150 Hz flicker is not even remotely acceptable. IMO this needs to comply with IEEE 1789.

Why not?

Re: Simple streetlight hack could protect astronomy from urban light pollution

#63

Post by uoaei »

petee wrote: post #2

In my area I've noticed the problem isn't so much that they are brighter, but that our new bulbs just emit light near 180 degrees (sideways) with no control over direction. It causes light to flood into homes, and more than half isn't even illuminating the road. They also have no diffusion, so its harsh on the eyes. A bad design all around

I often wonder how cutting and folding a bit of sheet metal and bolting it onto the streetlight as a shroud is overlooked whenever streetlights are built or repaired. There's one that shines directly into my bedroom but there's no good reason for it to illuminate any part of the building I live in.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#64

Post by amluto »

op00to wrote: post #62
amluto wrote: post #60

No. The article is light on details, but: > A simple device that makes LED lights flicker at a very high frequency that is imperceptible to the human eye > shutter, which needs to be lightweight and agile enough to blink about 150 times per second. Subjecting an entire city to 150 Hz flicker is not even remotely acceptable. IMO this needs to comply with IEEE 1789.

Why not?

Because of the rather well documented effects on health and visual performance.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#65

Post by Someone »

The hack is to make all lights in the neighborhood of an observatory flicker at “about 150 times per second”, and for observatories to ‘close their eyes’ when street lighting is on, giving up part of their light input (the article doesn’t tell, but I guess at least half of it. The LED lighting also will give up part of its brightness, but I think that’s less of a concern. It can easily be made brighter, if that’s needed at all)

I doubt that’s invisible to humans, though, and am fairly sure it is visible to many animals species, including some pets. https://en.wikipedia.org/wiki/Flicker_fusion_threshold#Displ...:

“For the purposes of presenting moving images, the human flicker fusion threshold is usually taken between 60 and 90 Hz, though in certain cases it can be higher by an order of magnitude.”

That’s already awfully close to 150Hz, certainly if all lights you see do that, but let’s ignore that, and read on, where we find:

“In some cases, it is possible to see flicker at rates beyond 2000 Hz (2 kHz) in the case of high-speed eye movements (saccades) or object motion, via the "phantom array" effect. Fast-moving flickering objects zooming across view (either by object motion, or by eye motion such as rolling eyes), can cause a dotted or multicolored blur instead of a continuous blur, as if they were multiple objects”

and

“The flicker fusion threshold also varies between species. Pigeons have been shown to have higher threshold than humans (100 Hz vs. 75 Hz), and the same is probably true for all birds, particularly birds of prey. Many mammals have a higher proportion of rods in their retina than humans do, and it is likely that they would also have higher flicker fusion thresholds. This has been confirmed in dogs.

Research also shows that size and metabolic rate are two factors that come into play: small animals with high metabolic rate tend to have high flicker fusion thresholds.”

TLDR: I don’t think this is a good idea, especially not given that the actual problem (FTA: “But there is a downside to LEDs: They're much brighter than old-fashioned energy-guzzling light bulbs”) is easily avoided. It’s not like we couldn’t replace light bulbs with LED lighting of equal intensity (and directed in the same directions)

Re: Simple streetlight hack could protect astronomy from urban light pollution

#66

Post by giantg2 »

probably_wrong wrote: post #59
todfox wrote: post #56

This doesn't help people like me who just want to stargaze. How about, empty city streets don't need to be lit up at 2 am. And what lighting there is, is too bright, too intrusive, and overused.

As a man I'm all for it. But I think the women I know would object to walking at night on pitch-black streets.

I think that's a bit sexist. While criminals will prey on people they think are weak and that often includes women, that's not exclusively so. I don't know that someone who is vulnerable would really be any safer in a well lit street at night, depending on other circumstances of course.

Cars have headlights. It could be that pedestrians can carry lights too. We could reduce infrastructure costs, electricity costs, allow pedestrians to be more conspicuous, and reduce the other negative impacts of constant lighting. You could even fund these personal lights for lower income people with the infrastructure savings.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#67

Post by HAMSHAMA »

giantg2 wrote: post #66
probably_wrong wrote: post #59

Earlier quoted context omitted.

As a man I'm all for it. But I think the women I know would object to walking at night on pitch-black streets.

I think that's a bit sexist. While criminals will prey on people they think are weak and that often includes women, that's not exclusively so. I don't know that someone who is vulnerable would really be any safer in a well lit street at night, depending on other circumstances of course. Cars have headlights. It could be that pedestrians can carry lights too. We could reduce infrastructure costs, electricity costs, al…

Maybe, but I have also heard this opinion independently from a few women in my life.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#68

Post by djbusby »

op00to wrote: post #62
amluto wrote: post #60

No. The article is light on details, but: > A simple device that makes LED lights flicker at a very high frequency that is imperceptible to the human eye > shutter, which needs to be lightweight and agile enough to blink about 150 times per second. Subjecting an entire city to 150 Hz flicker is not even remotely acceptable. IMO this needs to comply with IEEE 1789.

Why not?

When a bright light is extra annoying to light sensitive eyes it's because the lamp is actually blinking at a high frequency.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#69

Post by djmips »

amluto wrote: post #60

No. The article is light on details, but: > A simple device that makes LED lights flicker at a very high frequency that is imperceptible to the human eye > shutter, which needs to be lightweight and agile enough to blink about 150 times per second. Subjecting an entire city to 150 Hz flicker is not even remotely acceptable. IMO this needs to comply with IEEE 1789.

Also - it feels like it's not 'simple'. And I doubt it will ever be implemented.

Re: Simple streetlight hack could protect astronomy from urban light pollution

#70

Post by Terr_ »

giantg2 wrote: post #66
probably_wrong wrote: post #59

Earlier quoted context omitted.

As a man I'm all for it. But I think the women I know would object to walking at night on pitch-black streets.

I think that's a bit sexist. While criminals will prey on people they think are weak and that often includes women, that's not exclusively so. I don't know that someone who is vulnerable would really be any safer in a well lit street at night, depending on other circumstances of course. Cars have headlights. It could be that pedestrians can carry lights too. We could reduce infrastructure costs, electricity costs, al…

I think it's a bit like radar and sonar.

Receiving bounced waves gives you information, while emitting it gives out information, and may make you a target. A streetlight is a neutral-emitter that doesn't usually need to worry about being attacked, unlike a bobbing flashlight held by someone walking in the dark woods.

A difference with car-headlights is that the car itself is a protective shell, and it's hard for other cars to hide in bushes.

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