New street lights

[Fay]

Does anyone know if these new downlighters, in Bromley,  are  friendly to us or not?

[Carole]

Wasn't aware any were being installed, so i looked it up:

As part of a two year project we are replacing 8,000 lamp posts and installing 12,000 new light bulbs for the borough's Street Lighting Investment Project. Brand new state of the art Light Emitting Diodes (LED) lights will be installed and the borough's oldest concrete and steel lamp columns will be replaced with new steel ones. 

I have heard that LED ones emit light in the normal visual light spectrum and therefore LP filters are no use with them.  It depends whether they are going to be pointed downwards, if so might not emit so much light into the sky.

another quote:

.  Q: What if the light is too bright and floods onto my property?  A: LED light is a more directional rather than spherical glow so this problem should not occur. Although there is the potential for this light to have a higher intensity of brightness, the new infrastructure also means lights can be dimmed remotely from a central system. We would recommend a trial adjustment period of a couple of weeks once the new light is operational. If after that time you still consider the new lighting is adversely affecting your property we may be able to fit a device to shield out some of the light.

[Fay]

well did not really think they would benefit us 

[Carole]

Our needs are the last to be considered, but if the new lights point downwards, then they might be better as the light is not going up into the sky.

Carole

[Fay]

yes we will see

[Rick]

The trouble with them, at least where I've seen them, is that they are brighter, and have a wider-spread illumination cone than the full-cutoff sodium lights. From the council's point of view they'll be "better" because they should use a lot less electricity. From our point of view they'll almost certainly be quite a bit worse, partly because of the nature of the light, but mostly because of the brightness and spread.

If one appears anywhere nearby that shines into your garden then make a point of getting hold of the borough's lighting engineers and asking them to do something about it.

The Campaign For Dark Skies may well have helpful information on them...

[Mike]

When I lived in Orpington they installed them in the street and they certainly made the sky darker in the garden as they were better shielded and dimmer.

However, not the whole of Orpington had them and once the entire town has the LED lights then the reflected light may make the LP a lot worse in terms of being able to filter it out as its broadband spectrum rather than the sodium which was narrowband.

[Rick]

The ones round here are better than the old orange sodium lights, but not as well shielded as some of the newer full cut-off lights they were installing a few years ago. As far as my garden's concerned, shielding is what matters. I got the light out the front fitted with a shield so that my front garden doesn't get lit. A friend up the road has had a new light put outside his house, and he says he can read by its light in his upstairs bedroom, so it clearly isn't as well shielded as it ought to be.

[Fay]

Oh great Mike & Rick. I will see what they look like next time out

[MarkS]

The jury is still out on these from as astronomical point of view.  The light has a broadband spectrum which is impossible to combat with a light pollution filter.  But they give out less light overall and supposedly it is better directed and shielded.  However, they have a large component of blue light which scatters much more than sodium - so any light that does escape is far worse.  The shielding aspect really depends on their design - there are some terrible designs out there - like these: http://www.bbc.co.uk/news/uk-england-london-26910087
The Hounslow example used these horrible unshielded "stela" lights:  http://www.wrtl.co.uk/product-range/public-amenity/products/stela
The amount of light escaping sideways (destroying the night sky) also seems to be affected by whether they are mounted horizontally or tilted.  Most domestic "security" lights are tilted and throw out tons of wasted light.  I have fitted the horizontal design to my house which properly contain the light cone.

This report also mentions how badly designed LED streetlights cause dangerous glare for drivers: http://www.osa-opn.org/home/newsroom/2014/july/taking_the_glare_out_of_led_streetlights/?feed=News

I find that most of the current crop of LED streetlights are generally bad in terms of glare and so I tend to think they will also drown out astronomy in escaping broadband light.  However, I was recently driving out of Portsmouth on the motorway at night and was really impressed by the LED streetlights they used.  On a long section of road, the light was so well directed downwards that they were actually invisible until you got pretty close and looked up.  This solved the glare problem.  From a distance all you could see were the poles illuminated from above by the head of the light that was invisible until you got quite close.  It looked light someone had simply planted a row of poles down the side of the road.  I wish I had a photo of them both in the day and the night as a example of how lights should be designed.

Here is a similar view of the problems of the badly designed LED streetlights:
http://www.newscientist.com/article/dn26383-lighting-cities-with-cheap-glaring-leds-is-a-dim-move.html

Since Ashford Borough Council now has stringent planning controls on outside lighting (including the demand for directionality and limits on sideways light spill) I am hopeful that they will tend to install the better shielded variety.

Mark

[Rick]

Yeah, some of the new LED lights along Crofton Road from Locksbottom to Orpington Station are badly placed from a driver's point of view...

Bromley has a website for "Reporting a problem in Bromley's streets or parks" which might be worth a try if you can give specific details and a location.

[doug]

The Council have installed the new white lights where we live and I personally think they are an improvement over the sodium lights but as I don`t do imaging.... There is still one sodium light on an alleyway that shines into the back garden and the bedroom which is a PITA, but still, who are we to complain.

Doug.

[Rick]

They put a full cut-off high-pressure sodium light to replace one of the old yellow low-pressure sodium lights outside my house back in 2010. There are pictures of both old and new lights in the gallery at http://gallery.orpington-astronomy.org.uk/thumbnails-164.html

[Fay]

I assume we all have the same  lights in Bromley? not had a proper look yet

[Rick]

I suspect the ones they're installing around the back streets now are more-or-less the same throughout the borough, but they're probably not the same as the ones they were installing in the same sorts of places last year or the year before, and the ones they install on the bigger roads are definitely different beasts.