LED vs. sodium street lighting?

[marekintheuk]

In my neck of the woods (Cheshire, UK) this last year has seen many (most?) street lights changed from sodium the LED. My knee jerk reaction was was to curse - I have a UHC filter which does a good job of filtering out the main sodium lines, albeit with all sorts of other colour rendition problems. Now that I'm surrounded by broadband LED lighting, the UHC filter is less useful.

However on balance - and I don't have decent before-after data - I actually seem to have a significantly darker sky now (clouds permitting). The LED lights seem dimmer (neighbours have commented) and their light is directed well downwards. Perhaps my initial annoyance was unjustified?

What's been other peoples' experience of LED street lighting in a semi-urban environment? Good, bad? 

[Alien 13]

They are a big improvement in my view provided you are not in direct line of sight of one, I live very close to a city center and can easily spot the milky way now.

Alan

[pipnina]

My experience has not been great. The LED bulbs they've put in where I am seem to be brighter than the old yellow lamps, not dimmer. On the counterpoint they do seem to direct that light downwards better than the old ones.

If there is someone who does have good before/after photos, I'd love to see them.

[DaveS]

Before I left Ruislip they had changed from sodium to LED. I hoped that the sky would become dark enough that I wouldn't have to move to get dark enough skies. No such luck, on a very good night the sky would be marginally darker, but in most cases the blue light scatter made things worse. Probably too many sodium street lights in neighbouring boroughs to make a difference.

[chiltonstar]

A thing I notice is that there is a lot more scattered light around the LEDs cpd with the Na lights - the LEDs have an intense blue band which of course scatters light more than yellow.

There is pressure in some areas to put yellow filters on the lamps; this stops insects being attracted to them and therefore less cleaning. Also I believe there is evidence that bats are attracted to the moths flying around the lamps and are then predated in turn by owls.

Chris

[Charic]

1 hour ago, marekintheuk said:

I actually seem to have a significantly darker sky now (clouds permitting). The LED lights seem dimmer (neighbours have commented) and their light is directed well downwards. Perhaps my initial annoyance was unjustified?

Same here. I now need a torch to see the ground in my garden, such is the difference.
I recently erected a new 6 foot panel fence against my existing fence, which in turn blocks some of the sodium light coming trough the fence, but now the glare has gone, there's no reflection on the houses, and the garden is  much darker.

Not sure their dimmer, I find them blinding when I pass under them whilst driving, but notice just how  much darker the pavements and sidewalks are! Those folk , hooded ( nothing against hoodies themselves)  all in black have no chance if we as motorists can't see them, when they blindly cross the road without a care! cyclists too without their lights.

The led's are better shielded by their hoods. Before the sodium bulbs were visible, now the lights are more recessed, more directional, apart from one,  two gardens down, and right on their fence line, but not overly problematic if I keep my eyes below the fence line.

 

 

[johninderby]

Reading the various voews one question comes to mind. Are the LED lights in your areas just replacement bulbs in the old lamp heads or completely new lamp heads with a strip of LEDs?

[Charic]

I'm seeing mainly new lamp heads on existing poles, but some newer poles are much taller, especially along main roads?

[Ibbo!]

The replacements here were stuck on the old posts and are about 1m higher ?

[Demonperformer]

Well, I did some measurements with my SQM before/after they changed ours. I reckon from my front garden (where I usually image) there was an improvement of about half a magnitude, but I have got two lights fairly close by. But they are generally much more directionaly. I also measured a bit down the road away from any direct lights and I reckon the improvement here was closer to 1 mag, which fits in with the "directional" thing. But it is very dependant on conditions. If there is very much moisture in the air I reckon that things are now worse than the old lights, and I dread to think what the result might be if we get snow!

[BiggarDigger]

Our village was converted to LED lamp heads a couple of years ago.

We have a street light directly outside our property, about 10 metres across the driveway from the front door, which faces north.

The lamp heads are tightly focussed on the road.

Often,  on clear nights, when on dads taxi duty, I can see the Milky Way as I walk to or from the car even though the street light is just a few metres away.

The I can't comment on imaging, but I can say that I've seen more auroras since the upgrade and the rear of the house, where I do all my visual observing is very dark.

Richard