DOES ANYONE KNOW WHAT TYPE OF STREETLIGHT THIS IS?

[paulastro]

I have an interest as its just been put up outside  my neighbours house, about 20 minutes ago!  They are putting loads of them up to replace old ones over a wide area.

The second pic was a quick grab when they put it on briefly to test it.  The lighted bit consists of rows of small lights.

I've got my fingers crossed they are cut off lights aiming  the light downwards.  If they aren't, please break the news to me gently! 

The local pigeons will miss the old ones as they used the long arm at the top to perform their yearly nuptuals!

 

 

[Mr Spock]

LED light. When fully installed across the city where I am they turned the night sky light grey.

[wulfrun]

They are LED ones. The ones my council has fitted are awful, too bright and too much "spill". Hopefully you'll have better luck!

[IB20]

Yep LED lights, my local council did reduce their brightness when I complained about light trespass into a bedroom though. 😁

[paulastro]

2 minutes ago, Mr Spock said:

LED light. When fully installed across the city where I am they turned the night sky light grey.

Thanks for that.  Is the light grey worse or preferable than what went before for astronomy?

[paulastro]

1 minute ago, IB20 said:

Yep LED lights, my local council did reduce their brightness when I complained about light trespass into a bedroom though. 😁

Many thanks for that, it's useful information.  The previous lights spilled light everywhere so hopefully they may be an improvement!

[Mr Spock]

3 minutes ago, paulastro said:

Is the light grey worse or preferable than what went before for astronomy?

My sky to east was orange and my sky to the west clear with a little orange; I could see the milky way straight up and M31 too. Now I'm limited to around mag 4.5 in the west 

[paulastro]

6 minutes ago, Mr Spock said:

My sky to east was orange and my sky to the west clear with a little orange; I could see the milky way straight up and M31 too. Now I'm limited to around mag 4.5 in the west 

Many thanks.  I'll suppose I'll know the difference it makes around here soon enough.

[paulastro]

I suppose its not only the type of light, but the design of the housing?

In my pic the light panel looks to be recessed a little which may help, and it looks to be shaded from the rear.  Or am I being overly hopeful?

[Elp]

They look the same as the ones around here. Great for illuminating EVERYTHING around. The light spill into the house is very similar in intensity and colour temperature to pre dawn light.

 

[powerlord]

Don't worry - if they're like the ones around here they are 'smart' and turn off when it gets dark. yes..I do mean that.

Apparently the point of street lights now has changed. Unclear to me what the definition is now tbh-but it does not appear to be to 'light up streets at nights'... around here they turn on after dusk, then switch off at 11pm. Because.. reasons.

On the one hand I'm not compaining as it means light pollution has plummeted in the last 2-3 years by 11pm or so.

On the other hand,  if I had a teenage daughter walking home late at night on streets and lanes, I might wonder if we've regressed to the dark ages (sic).

stu

[Zermelo]

10 minutes ago, paulastro said:

I suppose its not only the type of light, but the design of the housing?

In my pic the light panel looks to be recessed a little which may help, and it looks to be shaded from the rear.  Or am I being overly hopeful?

Yes, that is something.

When they did my road, they directly replaced the low-pressure sodium bulbs with swap-in LED versions. Because the existing fitting within the housing was 2-3 cm below the flat upper surface, it meant that the light could spill out of the sides, even above horizontal.

Other factors will be:

- brightness. Many of the LED street lights are much too bright. Even if the light is directed downwards, it can be so bright that a lot gets reflected up from the road, especially if it's wet.

- colour temperature. Many of these lights have a very broad spectrum, including a fair amount of blue.

You won't really be able to judge until it's dark.

From an observing perspective, I'm not sure that any of the LED replacements are better than low-pressure sodium (orange) lights. But your new ones may be among the better LEDs. Please let us know.

[Elp]

I'm positive my garden plants are reaping the benefit, they've just exploded since.

[bosun21]

I have the same few lights out the front of my house but zero out in the rear of my house (phew!) They definitely spill light out horizontally and are bright.

[Louis D]

Low pressure sodium (LPS) lamps are quite easy to filter out with just about any light pollution filter.  Not so with an LED lamp.  Just look at the spectrograph below to understand why:

That's why traditional light pollution filters will be rendered nearly obsolete in the very near future, if not today in many locales:

[powerlord]

true but @Luke Newbould had a good video about this. He stated that unlike sodium lamps, the LEDs ones, since they are far less bright tend to almost always be focused down. As apposed to old sodium ones which very often spilled tons of light all round and back up. He stated that he has found, at least for all the LED street lights that have replaced the sodium ones around his area, that it has massively REDUCED light pollution and totally eliminated the need for light pollution filters.

 

[Louis D]

In my neck of the woods, my dull orange skies have turn bright gray as if there is a gibbous moon somewhere in the sky.  In fact, in the middle of the night, it almost seems like twilight.  I'm blaming much of that on overly bright LED lights reflecting off pavement.  It's so bright, some drivers forget to turn on their headlights at night.

Edited September 13, 2023 by Louis D

[RT65CB-SWL]

The joys of urban-astronomy. I have to contend with these three LED streetlight designs…

 [1.]

 [2.]

 [3.]

[1.] This streetlight is shielded, (after I complained to my local authority/council), at the end of a footpath/communal lawn where I mainly set up my ‘scopes and observe from when at home.

[2.] At the other end of the footpath… and no shield. I have asked the local authority/council for this to be shielded too. As it does not interfere with my property, there is little I can do to raise a complaint.

[3]. This streetlight is on the pavement of the main road. Nothing much can I do about this one!

 

 

[Zermelo]

1 hour ago, powerlord said:

true but @Luke Newbould had a good video about this. He stated that unlike sodium lamps, the LEDs ones, since they are far less bright tend to almost always be focused down. As apposed to old sodium ones which very often spilled tons of light all round and back up. He stated that he has found, at least for all the LED street lights that have replaced the sodium ones around his area, that it has massively REDUCED light pollution and totally eliminated the need for light pollution filters.

 

One of the annoying features of the switchover is the lack of consistency between local authorities/their chosen contractors, and the slow emergence of best practice.

Some have done their research, and sourced and fitted new units that direct the light downwards, make them no brighter than absolutely necessary, remove the blue end, and automatically switch them off at some time.

If such a scheme replaces older lighting that was intrusive, then it is possible that it might constitute an improvement (though the point about filtering would still apply). Too many do not.

[Swoop1]

1 hour ago, Louis D said:

In my neck of the woods, my dull orange skies have turn bright gray as if there is a gibbous moon somewhere in the sky.  In fact, in the middle of the night, it almost seems like twilight.  I'm blaming much of that on overly bright LED lights reflecting off pavement.  It's so bright, some drivers forget to turn on their headlights at night.

I think it is probably the car’s auto light switch being fooled into thinking it is not dark enough. Lots of drivers rely on their car to do the thinking for them….

[Mandy D]

Walking home a few night ago from a friends house after we'd been drinking, so left the car behind, we noticed that the leaves on trees were acting as pinhole cameras and producing muliple images of the light array on the pavement, just like we get images of the Sun on the pavement in daytime. As a migraine sufferer, I find it very uncomfortable. Not enough research effort is being put into lighting systems and schemes and the same can be said of car lighting. Apparently, it is only epileptics who are considered in the government research with regard to lamp flicker. The pulse width modulation flashing on car tail ights is particularly irritating to migraine sufferers, but is OK according to the government because we don't count. Apologies if I have rambled off topic, here.

[paulastro]

3 hours ago, Zermelo said:

Yes, that is something.

When they did my road, they directly replaced the low-pressure sodium bulbs with swap-in LED versions. Because the existing fitting within the housing was 2-3 cm below the flat upper surface, it meant that the light could spill out of the sides, even above horizontal.

Other factors will be:

- brightness. Many of the LED street lights are much too bright. Even if the light is directed downwards, it can be so bright that a lot gets reflected up from the road, especially if it's wet.

- colour temperature. Many of these lights have a very broad spectrum, including a fair amount of blue.

You won't really be able to judge until it's dark.

From an observing perspective, I'm not sure that any of the LED replacements are better than low-pressure sodium (orange) lights. But your new ones may be among the better LEDs. Please let us know.

Many thanks Zermelo, it sounds like a little hope there.  My hope is that it won't be much worse than it was before - Bortle 5 I think, but I've never measured it myself.

Its not only street lights of course.  Like for many of us , so called neighbours  of mine don't desist from putting bright lights on when it suits them, even if I'm observing. 

I always put a dark hood over my head when observing and its possible to almost forget I'm not under a more reasonable sky at times.  This is helped by having a ten inch scope which is big enough to give  me access to much better views than when I had a maximum aperture of four inches at home up to about eighteen months ago.  Years ago I used bigger scopes   scopes but then had a long mostly refractor phase before seeing the light and having  larger aperture scopes once more 🙂.

Nothing against refractors, but the older I've got I've needed bigger scopes to give me better views - just the aging process.

I've never really used broadband visual filters, only UHC and O111 when they are helpful.

Anyway, I'm rambling, that's an age thing too 🙂.  I will post up how the new  lighting affects the sky when I've had some clear skies.  This could be a few days as I'm posdibly away from home  for a few days soon.

 

[DaveL59]

The one across the road from me was way too bright and sat on the sofa it'd be just nicely aligned to cause glare to my eyes it was that bright. It did however help find the keyhole when returning home in the dark lol. How the neighbour opposite tolerated it lighting up their bedroom tho was another matter and I expect they complained as for a while now it dims from around 10PM or so. Flip-side of course is I now have to fumble about truing to get the multi-ridged security key into the door lock to get in, first world problems huh 😉

Sadly here too the sky is grey since the past couple years compared to the velvety black it was when I moved here 7 years ago. The Brexit lorry park a bit further down the M20 sure didn't help that along with the blanket replacement of old with LEDs all around.

 

[Astronomist]

This one is directly across the road from my house, and illuminates my favourite telescope set up position. One of these on a street near me has had its bulb painted over black (possibly a local astronomer- anyone want to confess?)

[Mandy D]

4 hours ago, Louis D said:

Low pressure sodium (LPS) lamps are quite easy to filter out with just about any light pollution filter.  Not so with an LED lamp.  Just look at the spectrograph below to understand why:

 

LEDs are monochromatic light sources. They do not produce broad band spectra, which is why we see the big spike at around 430 nm ( blue). To get white light from LEDs there are two common methods, one is tri-colour, with red, green and blue emitters which, when the light is mixed in the correct ratio, produces an approximation to white light. The second method, is the most common and certainly being used in street lights and most other "white" light sources. The blue photons carry high energy (remember E = hν, h is Planck's constant and ν is the frequency associated with the photon), which exceed the level needed to excite fluorescent materials which then release visible photons in a broader band which can be seen rising to the right of the main spike and then tails off at longer wavelengths. The fact that 430 nm LEDs are used, explains the high blue content in the spectrum of "white LEDs".