If that is a "simple device", we can add it to computers to help synchronize time? For distributed databases it would be helpful
Simple streetlight hack could protect astronomy from urban light pollution
141–150 of 159 posts
Re: Simple streetlight hack could protect astronomy from urban light pollution
#142Earlier quoted context omitted.
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 othe…
Street lights still have shadows and areas that they don't cover. You still have things like the opposite side of cars that you can't see even if you have a street light (ie your bushes example applies with or without street lights). When I say to carry a light, I don't mean the light on your phone, but a proper means of illumination. If done correctly, this would provide plenty of information before in attack range (assuming you're not getting shot at long range, which isn't really an issue in common crime today). There are also defensive tactics with the lights that can benefit you. For example, if someone is waiting in the dark for you (as your comment implies) and you blast them with 1200+ lumens maybe even in strobe mode, you now have the advantage, streetlight or not.
So yeah, you can give out some information by holding a light, mostly about position. You give out much more information being in the light from street lights, such as sex, age, weakness/disability, etc that are more useful to criminals.
The are plenty of areas without street lights or with minimal street lights today. The primary issue as it pertains to crime is not a lack of street lights, but other factors such as socioeconomic factors and defensive knowledge.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#143No. 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 do you think 150Hz is unacceptable? People used to watch 50Hz TV, and weren't bothered too much. And San Jose used to use 60Hz flickering streetlights (sodium? not sure) to reduce light pollution for Lick Observatory.
Pre-LED stadium lights do indeed flicker pretty egregiously, but, when correctly installed, they would be balanced between all three phases, so at least the average illumination was roughly constant.
I don’t know why TVs weren’t headache-inducing. Certainly old CRT computer screens were extremely unpleasant to look at at lower refresh rates.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#144Earlier quoted context omitted.
Its often the most offensive shade of bright white fluorescent-like LED. Why can't they do the orange one that lets everyone be ok seeing light at night and sleeping to tell the tale
LED it's more power efficiencient . However, there are LED light bulbs that have some kind of filter that makes it more ambient and astronomy friendly. Normal white LEDs are a nightmare for astronomy, because his light spectrum it's hard to block with any kind of "anti light pollution" filters.
2800k LEDs are not filtered white light afaik.
A bit of background for those who may not be aware, white LEDs are UV LEDs with a white light emitting phosphor. I suspect 2800 K LEDs are a UV LED with a 2800 K light-emitting phosphor.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#145Earlier quoted context omitted.
LED it's more power efficiencient . However, there are LED light bulbs that have some kind of filter that makes it more ambient and astronomy friendly. Normal white LEDs are a nightmare for astronomy, because his light spectrum it's hard to block with any kind of "anti light pollution" filters.
2800k LEDs are not filtered white light afaik. A bit of background for those who may not be aware, white LEDs are UV LEDs with a white light emitting phosphor. I suspect 2800 K LEDs are a UV LED with a 2800 K light-emitting phosphor.
Whats the orange one? I've seen pics of streetlamps like that unless its a MandelaEffect or somethint
Re: Simple streetlight hack could protect astronomy from urban light pollution
#146Seeking advice on how to lobby my city to disable a streetlight. We are on a rural road next to conservation land, and it blasts our house with light through the night, distracting our son with autism. Considering getting an instrument to measure the light's intensity and gathering data. Any tips on how to lobby a city government with such an unusual request would be greatly appreciated.
Do all that but have you considered good blinds and maybe even a sleeping mask? I'm on your side but good tools to have for anyone, particularly with or without such a condition. The sleeping mask Tim Ferriss recommends is amazing, I hate sleeping without it
Also make sure he makes his phone/screen orange-tinted at night and let him pick out an album or book he loves and teach him to listen to it every night. Slow down the speed as far as he'll tolerate and set a sleep-timer for like 1.5h to fade it out. Also, turn down the volume just so he can barely hear it and has to strain a bit to hear it.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#147Earlier quoted context omitted.
Different types of transformers introduce different phase shifts.
Couldn't you still account for offset?
Maybe? I guess you could "calibrate" it with GPS. I don't know how consistent the phase at a specific location really is in practice on long timescales.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#148Earlier quoted context omitted.
I'm not sure I'd be so quick to dismiss the feasability, at least not based on your reasoning so far. FM Radio stations have managed to accomplish getting the speaker in your car radio to "blink synchronously" according to a complex signal pattern in the exact same way as millions of other radios simultaneously.... for about a century now. As long as all streetlights are in locations with good radio reception (which,…
Okay, let's do some math. Very rough napkin numbers, but it'll get us close. A 150Hz blink rate means a period of 1/150s, or ~6.7ms. The speed of radio signals through air near the surface is a bit lower than c, let's call it 299,250 km/s. [0] When you multiply those numbers you get ~1500km. That means each 'on' and 'off' signal is 1500km long, moving near c. More specifically, the signals are concentric rings around…
I’m not a physics person, but couldn’t this be easily solved by adding a programmed delay that corresponds to the distance from the transmitter? Street lights aren’t known to migrate.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#149> But there is a downside to LEDs: They're much brighter than old-fashioned energy-guzzling light bulbs. Are light bulbs actually being used in street lighting? I can't recall ever seeing that. Typically there's some gas-discharge lighting for that, and as far as I know, good old sodium-vapor lamps are pretty energy-efficient, on top of being not-terrible for astronomy. This makes me wonder: what are LEDs replacing?…
Cheaper to operate, which over an entire city's worth of street lamps is very material. Sodium-vapor lights eventually need to be replaced (as do LEDs), so why not replace them with a modern technology that's cheaper to operate?
Common low pressure sodium and white LED street lights are about the same in efficiency: around 140 lm/W. LED street lighting pollutes the night sky with light that astronomers find impossible to fully compensate for, impacts wildlife (and probably not in a good way), inhibits low-light vision adaption in drivers and pedestrians, and gives public areas all the attractiveness of an operating theatre. All this for a dubious promise of savings after tens of millions of initial investment from each local authority.
Re: Simple streetlight hack could protect astronomy from urban light pollution
#150Earlier quoted context omitted.
Just shoot it. It'll never get noticed.
I'm not going to advocate for illegal activities but unfortunately this is the most practical solution in most of the US. That said, do NOT shoot anything with a real firearm. Even small caliber bullets travel for miles. Walking out at 2am with a red ryder BB gun and plinking it would work just fine.
A bb gun might not do the trick but a pellet gun would. I mean, hypothetically...