Some new streetlights

[Demonperformer]

New streetlights have been installed on the road running past the end of my road, but along my road we still have the old ones. This is part of the (apparently) haphazard order in which the local lights are being replaced, but has given me the opportunity to do a few comparisons.

This morning (wet conditions after yesterday's rain - I've seen it reported that this can make the new lighting worse) I wandered down the road with my SQM meter and found a spot that was opposite one of the new lights with another one just along on my side of the road. This is roughly the alignment I have from my front garden, although the devil could be in the detail, but it was the best I could do. Zenith SQM reading: 18.81.

Went back home and took a reading from my front garden: 17.98. Maybe not a massive difference, but not an insignificant one either.

A few anecdotal thoughts:
(1) On the way down the road, one of the streetlights got into a position where it was directly in front of a big tree (a black background) and the moisture in the air made it very clear that the light was in a cone pointing downwards, with virtually no light shining directly upwards or out horizontally. [It was of course me that was moving, not the streetlight :D]
(2) Looking at that line of lights from my bedroom window, there is a noticeable "cut-off" point, below which is quite bright, but above which it is a lot darker. These two points would seem to suggest that the new lights address the issue of light being shone where it is needed, rather than into the sky where it isn't (a thing I heard Sir PM go on about at length many times).
(3) Slightly further afield, a game I used to play on cloudy nights from my bedroom window was to make constellations from all the orange streetlights I could see in the surrounding area. I'm in a bit of a dip, so there were lots of them at various ALTs. Most of these have disappeared, having been replaced by the new lights and these are no longer visible, so the 4/5 that are left do not give much scope for different "constellations".

OK, nothing too "scientific" about all of the above, but I am left with the impression that, as long as I am able to shield the front lenses of my scopes (frac & sct) from direct light (which the dew shields seem to do quite nicely), things may actually be a bit better in the sky itself when all the lights are replaced.  I should probably make it clear that I do very little in the way of "visual", almost all imaging, so dark-adaptation is not such an issue. Much as it may stick in my craw to say this, I think Poole BC may actually have done something right for a change!

Thanks.

[Pig]

DP,  in Northampton we have benefitted from the new lights for quite some time now and they have made quite a difference. I think when the dual carriage ways / ring roads are fitted with the new lights is when I believe we will all have the greatest appreciation of the change as they are much brighter and there are loads of them.

Your method of actually going and having a look is as good as any because you get an actual experience of the change rather than just reading about it

[Dave In Vermont]

"When a puppy makes a "mess" on the carpet, instead of waiting to go outside, you don't reward it with a Doggie-Treat." This also applies to politicians and city-councils. However - when a puppy is obedient and asks to go outside, you do reward it. Why? I'll tell you one good reason.....

They may have just gotten a good price from a company that sells these streetlights cheap and they just happen to be shielded to direct the output of light downwards. If so - they have no clue of these being beneficial to a wide range of people - including astronomy-enthusiasts. So if they get around to doing the new lighting elsewhere, it would be a gamble that they'd manage to do the right thing again. Unless someone brings this "good job!" to their attention, and gives them a list of reasons. This way they will be conscious of wanting shielded lights for any future works.

These folks can help you (Yes - YOU! ) assemble a nice 'Congratulations - you got my vote!' letter:

http://darksky.org/

An activist in my other lives -

Dave

[Pig]

If my dog asked to go outside it would frighten the freaking daylights out of me

But you do make a great point Dave, it can only result in a positive outcome if praise is given where its due.

[laudropb]

In our street we have had the new lights fitted since January. They have still not turned them on !! Must have ran out of money.

[Dave Lloyd]

1 hour ago, laudropb said:

In our street we have had the new lights fitted since January. They have still not turned them on !! Must have ran out of money.

That's one result.

[Dave Lloyd]

8 hours ago, Demonperformer said:

OK, nothing too "scientific" about all of the above, but I am left with the impression that, as long as I am able to shield the front lenses of my scopes (frac & sct) from direct light (which the dew shields seem to do quite nicely), things may actually be a bit better in the sky itself when all the lights are replaced.  I should probably make it clear that I do very little in the way of "visual", almost all imaging, so dark-adaptation is not such an issue. Much as it may stick in my craw to say this, I think Poole BC may actually have done something right for a change!

Thanks.

Maybe it will turn out that the broadband aspect of LEDs will be offset by improved directionality.

[laudropb]

Unfortunately we still have the old orange ones on.

[Demonperformer]

UPDATE

They installed the new lights on our road a couple of days ago (actually, they have still to fill in the holes, but the lights are in/on). So, a few more comparisons this morning.

1. "Down the road", the reading was still 18.8, so 'other conditions' would seem to be 'the same' or at least similar enough for them not to affect the result.
2. The reading from ny observing spot in the front garden was 18.44, which is just shy of half a magnitude improvement on my previous reading.
3. Back in December, I did some tests from my bedroom window and outside pointing the meter at the streetlight [https://stargazerslounge.com/topic/258681-email-to-my-councillors/]. The comparison results are:
(i) Through curtain: old=17.8, new=18.3 (improvement=0.5)
(ii) Without curtain: old=13.7, new=14.4 (improvement=0.7)
(iii) directly outside my front door: old=12.2, new=12.8 (improvement=0.6)
4. Pointing roughly at the streetlight, the "drop off" as you move away from it is quite dramatic. My first attempt to do this reading produced a result of 15.3, which I didn't believe so I went and retook it. I was obviously pointing a little above the lamp. Moving the meter a tiny fraction down increased it to just over 14, and it peaked at 12.8. I would suggest that this indicates the effective way in which the light is directed downwards.
5. My "general impression" (not a scientific term, I know) is that, at ground level, it appears a lot brighter than it used to be. To what extent this is due to directionality and to what extent it is because the light is white rather than orange, I do not know.

All in all, I am going to repeat my assessment in my original post. For imaging, if I keep the front end of my scopes shielded from direct light, I think the results (if the skies are ever clear enough for me to be able to get any!) are likely to be better, because the sky at which I will be pointing will be "darker". But for visual, I think things would be a lot worse, as my eye would get even less dark-adapted than under the orange lights.

We'll see ...

PS. @ Dave: Now "my" streetlight has been changed, I will be doing a follow-up email to my councillors (as you suggest) to congratulate them on this improvement.

[Linda]

For visual you could consider using an observation hood. You can easily make this yourself from a piece of cloth. Or you could throw a dark towel or t-shirt over your head.

What I do at home is hanging up some green sheet from the building store when I go observing. In my case it is not the community, because we don't have any street lights. But therefore all houses have 4-8 outside lights that are not shielded in any way and that turn in when it is dark.

[Scosmico]

DP, at ground level the reduction in light glare increases the sense of brightness. Pupils dilate as no glare come to the eyes.