‘Dark Skies’ Parliamentary Group launched

[SteveNickolls]

He, he just our luck to get the light pollution turned down just in time to see all those LEO satellites. Just a thought.

 

Cheers,
Steve

[Nigella Bryant]

All LED lighting around me, council was very understanding and shielded light's near my property and one further away goes out late evening. Also I find the LED interference is easier to deal with with a D2 filter than the old sodium lighting. Devon county council seem to be more enlightened about amature astronomer's lighting needs. I guess this needs to be more national than local experience.

[Dave Lloyd]

I think there could be a lot of lobbying against this initiative by self interest groups ie lighting and security industries and dare I say it even the police. 

[ScouseSpaceCadet]

5 hours ago, ian2 said:

The LED street lights installed around here by Aberdeenshire Council appear brighter and with a much whiter light than the dull glow of the old sodium lamps. 

That's true for all LEDs, but the theory is, the lamp if aimed down and shielded on the top, *should* contribute far less to sky glow compared to older lamps, while still adequately illuminating the ground area. So you're lit up like Christmas on the ground, but the sky quality above is better than before.

Pants for the observer under the lamps, but better overall. Catch 22... 

 

[Pixies]

5 hours ago, ian2 said:

The LED street lights installed around here by Aberdeenshire Council appear brighter and with a much whiter light than the dull glow of the old sodium lamps. 

The ones going in, in Edinburgh are much dimmer. They won't reach this side of Edinburgh until spring next year.

Unfortunately, there are already complaints that they are too dim and the council has agreed to raise the levels once everything has been completed. It does seem as if they have control of the lights centrally. That bodes well for future fine-tuning. Perhaps I could contact the council and ask them to dim one in particular!

Also, as Edinburgh does not have any streetlights that go out during the small hours, perhaps now there will be an opportunity to be able to do so?

[ian2]

Is skyglow caused by direct light shining upwards or light reflected up from the ground? Snow, for instance, appears to enhance reflection upwards from the ground.

 

 

[PeterW]

Some work a while back showed forward (mie) scatter from light emitted “close to the horizontal”, so full cutoff (and hopefully better fixtures) will constrain the light into a pool below them, rather than spreading it all the place.  If it’s going straight up, almost none will come back. There will be reflection and scatter off the ground, which can add a bit  Another study I saw modelled the sky glow spread and showed that fitting full cut off fixtures in a city would drastically shrink the light foot print and improve the skies around. 

when you walk about the place how many streetlights are shining in your face even though they’re miles away and so can’t possibly provide any useful light at your location?? 
the focus has to be on penalising any fixtures that spray light outside of the area where the illumination is needed.... efficiency and safety (less dazzle). Justify why your light has to illuminate my bedroom?! 
The new LEDs near me are essentially invisible from only a short distance away, no dazzle and yet the ground underneath still has the right level of light. Of course then we can discuss that the light he tends to be bluer, which introduces additional issues. 

 

peter

[Aramcheck]

1 hour ago, ian2 said:

Is skyglow caused by direct light shining upwards or light reflected up from the ground? Snow, for instance, appears to enhance reflection upwards from the ground.

It's caused by a combination of:-

• direct emission of light into the atmosphere,
• scattering of light by atoms & molecules in the air (Rayleigh scattering) + scattering of dust/water droplets (Mie scattering)
• reflection of light from the ground & other surfaces

Scattering of light emitted at or close to the horizontal is a major factor in skyglow which is seen many miles from the source.

The US Dept of Energy did some interesting modelling of skyglow from different light sources:-
https://www.energy.gov/sites/prod/files/2017/05/f34/2017_led-impact-sky-glow.pdf
https://www.energy.gov/eere/ssl/potential-impacts-led-street-lighting-sky-glow
https://www.energy.gov/sites/prod/files/2017/08/f35/Sky-Glow-Webinar_7-27-17.pdf

The only paper I've seen where measurements have been taken of a city before & after LED lighting was installed is in Tucson:-
https://arxiv.org/abs/1802.03474

(If memory serves this showed approx 7% reduction, but isn't conclusive as they had equipment changes between the before & after measurements)

Cheers
Ivor

[Stardaze]

On 10/02/2020 at 14:15, Ships and Stars said:

I do have to agree with the comments that there isn't currently much that can be done. I'm facing the imminent installation of fourteen new unshielded 1,000 lumen dome LED flood lights (yes, 14,000 lumen) along the rear of a business facing our house. They will literally be pointed at our house and the sky above from less than 20m away. The current plan is for them to stay on all night, except three that are already installed without notice - I convinced the health office to get them to turn those off early evening.

I was notified a year ago of this by local planning and immediately filed a detailed objection citing Env Health Regs, Statutory Nuisance, light intrusion, etc, proper type and placement of lights, etc but was flatly ignored.

I've already spoke to the Env Health Officer, but he can only put a word in for me.

The electrician said he would install one and see what I thought, but that means they've already bought and plan on using them.

People don't get it. 

We will have to move, or get a solicitor, fight it, and still probably end up moving...

 

 

 

As a lighting engineer, you should be able to request the design detail and it should not be over-lit. The urban standard is 30 lux (15 in rural areas) and so anything above that is unnecessary. LED lighting is much easier to control light-spill over traditional lighting and if flood lights are needed for large areas (car parks) then asymmetrical versions are best, as they are mounted on the horizontal axis. If it’s just building security (5 lux), then there are alternative options that control light-spill. 
Some councils are very strict in my experience, but residents do have a strong voice where lighting is concerned. They will be able to have a lighting design produced to quantify light-spill on neighbouring properties. Obviously the glare directly from the luminaries will come down to the types used.

[ian2]

Peter and Ivor, thanks for the detailed responses and for the links to the articles this was exactly what I was looking for.

regards

Ian

 

 

[Aramcheck]

Just a reminder that the APPG consultation on Dark Skies & Light Pollution ends tomorrow, in case anyone still wants to give their 2p:-

https://appgdarkskies.co.uk/dark-skies-consultation

Cheers
Ivor

[PeterW]

Thanks for the reminder, had drafted some rambling notes, just tidied them up and added a bit and posted. Will be interesting to see the report that comes from this and how it will be championed so it delivers long lasting benefit.

Peter

[Aramcheck]

https://twitter.com/i/web/status/1311680927639244805

"Thank you to all those who took the time to respond to our consultation.
We have received over 150 submissions, giving us so many great ideas about how we can start recommending viable policy solutions to deal with the growing issue of light pollution. Watch this space!"

Cheers,
Ivor

[PeterW]

I woz one. Now to edit down 150000words to something targeted, punchy and actionable. We are watching eagerly and hope that our view of space gets better too.

Peter