Author Topic: Light pollution maps  (Read 909 times)

ciomasbure

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Light pollution maps
« on: December 24, 2017, 02:56:30 AM »
Hi!
Thought it may be good with a thread with all the possible light pollution maps accumulated in 1 place.

This one reveals pockets of better sighting places in for example urban areas: https://www.lightpollutionmap.info/

This is for individuals looking for TRULY dark skies: http://darksitefinde...maps/world.html

And here is the way things are looking out, impacting how it looks down here: http://www.blue-marb...ghtlights/2012

More?



John Pfister

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Re: Light pollution maps
« Reply #1 on: December 29, 2017, 03:30:47 PM »
All of the maps are inaccurate in many populated areas due to the advent of well-shielded LEDS. I know for a fact that I am no longer in a red zone.

Charlie Collins

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Re: Light pollution maps
« Reply #2 on: January 04, 2018, 03:47:44 PM »
I assume this is what can becombined with the darksitefinder: http://www.bigskyast.../lp_bortle.html, and where you once were...

ulatimhan

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Re: Light pollution maps
« Reply #3 on: January 04, 2018, 05:51:18 PM »
Quote
All of the maps are inaccurate in many populated areas due to the advent of well-shielded LEDS. I know for a fact that I am no longer in a red zone.

Not sure what you are saying. You're saying things have got worse now? Or that things have improved?

Mark

Travis Vega

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Re: Light pollution maps
« Reply #4 on: January 08, 2018, 03:16:33 AM »
Thanks. I feel a little better about my back yard due to the high-resolution map. It's also given me some ideas about scouting out some nearby places to go. I'm also wondering if it's worthwhile identifying the worst near-by polluters and trying to convince them to tidy things up a bit?

Edited to add:

It can also function as a gas station finder along rural interstates. Just look for the green blobs.

presalacder

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Re: Light pollution maps
« Reply #5 on: January 08, 2018, 06:33:51 AM »
Quote
Quote

All of the maps are inaccurate in many populated areas due to the advent of well-shielded LEDS. I know for a fact that I am no longer in a red zone.

Not sure what you are saying. You're saying things have got worse now? Or that things have improved?

Mark
Improved.

ricoperte

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Re: Light pollution maps
« Reply #6 on: January 08, 2018, 02:31:42 PM »
Nice to hear.

Here is some discussion about the different maps: http://www.cloudynig...ksitefindercom/

Warren Tucker

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Re: Light pollution maps
« Reply #7 on: January 08, 2018, 02:46:59 PM »
Maybe this can add someting? Yet another slightly different color scale, pink in the city for example: http://cires.colorad.../artificial-sky

Jacob Cota

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Re: Light pollution maps
« Reply #8 on: January 10, 2018, 05:13:43 AM »
In all honesty the oldest maps are likely to be more accurate in general terms than are the newer, higher resolution, examples in most regions. It is naive to think that," things seem to have gotten better" for the individual simply because the newer map says so when nothing in the area has physically changed. It has been my personal experience that, at least in the northeastern U.S. that the latest maps are underestimating the intensity/impact of existing light pollution, especially in the region around the megolopolis.

BrooksObs

Ralph Sonberg

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Re: Light pollution maps
« Reply #9 on: January 11, 2018, 02:10:45 PM »
I'm just trying to stay positive...

Getting the best possible observing place with the least effort. Not much to do about the big wheels.

Personally I'm combining ground view with the light pollution map ("hybrid") for getting a decent place, with free sight to the south, that is a field etc. https://www.lightpol...layers=0BTFFFFF

Rodney Slater

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Re: Light pollution maps
« Reply #10 on: January 13, 2018, 12:01:59 AM »
Your second link is the only truly useful one, and in my experience is pretty accurate. If anything sky conditions are a little worse than what the map says. Light pollution is getting worse, even if they're using 'well shielded LEDs' the problem is only getting worse as the LEDs are so bright it all gets reflected off the ground and skyward.

https://media.giphy....ZsYvu/giphy.gif

tanktositsoft

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Re: Light pollution maps
« Reply #11 on: January 13, 2018, 07:19:44 AM »
Quote
In all honesty the oldest maps are likely to be more accurate in general terms than are the newer, higher resolution, examples in most regions. It is naive to think that," things seem to have gotten better" for the individual simply because the newer map says so when nothing in the area has physically changed. It has been my personal experience that, at least in the northeastern U.S. that the latest maps are underestimating the intensity/impact of existing light pollution, especially in the region around the megolopolis.

BrooksObs

This is definitely true. Like any map, these are half the story at best. At least in my experience. VIIRS 2016 (and "blue/black marble," etc - anything that uses a satellite measurement) are just not accurate in terms of showing me what the sky is like in a specific spot; it is showing the very bright spots, but not the "residual" effect of the light domes caused by those population centers (and that's all it's intended to do from what I understand). My personal experience is that the low-res maps from 2006 are now quite a bit understated; 10 years later the pollution levels have gotten much worse everywhere I've looked. To some extent the reverse is true too. You can find places that, for whatever reason, have better skies than another spot not a mile away, just by getting out and doing a lot of exploring.

I live in what (in the eastern US anyway) would be considered a pretty rural area. The outskirts of the closest major city to me are about 50 miles away (as the crow flies) - population 650,000. I'm still well within that city's light dome. The closest minor population center ( < 15,000 total population) is 15 miles away. There are no streetlights within 10-12 miles of me, the closest interstate is 20 miles away, and my nearest neighbor is almost 1000 yards away across a rolling field (and he keeps his porch light on most nights, but that's it). My skies are a solid Bortle 5. I can drive for 30 minutes (to a 170k acre park) and be in a 4, maybe a high 3 on an exceptional once-in-a-blue-moon good night. That's as good as the skies get within 500 miles of me in any direction (and anywhere I've bothered to look between FL and Indiana, even including some very large wilderness areas in Appalachia, maybe excepting a few places in WV).

I sometimes chuckle at friends who visit me and comment on how dark it is at my house at night. It is darker than a city, sure, but there is still enough "ambient" artificial light that it never really gets inky-black. They live in areas where it is NEVER DARK, ever. Not even dark enough that you couldn't read a book. That's almost as tragic as the fact that people who live in areas like that never even think about it anymore.

Not being an expert on ambient light, I suspect there are lots and lots of factors at play here that a map won't ever be able to show you. Obvious ones like population density (not just the overall population of a city), but also things like elevation, average humidity, smog and other "air quality" issues around cities (also affected by elevation), and who knows what else.

Anyway, the point is this - others may disagree, but I've never seen dark skies within 150 miles or more of any population center, even a smaller one, and I challenge you to find such a place east of the Mississippi in the US. The light dome, even of something like an well-traveled highway, convenience store parking lot, etc, is actually pretty incredible. One poorly-shielded LED light can ruin an stupidly large area (can cause a dome with a radius of a thousand yards or more - that's from personal observation, not a guess).

And having lived in this general area for quite a while, I can definitely say it's getting much, much worse, at a rate that is actually very alarming.

Robert Donaldson

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Re: Light pollution maps
« Reply #12 on: January 13, 2018, 02:44:36 PM »
Looks we are playing in a different league. I'm trying to even see some dimmer stars, and a glimpse of the Milky Way. "All is relative" somebody said.

firorectve

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Re: Light pollution maps
« Reply #13 on: January 13, 2018, 04:00:34 PM »
Think I will take a bit ofthe advice here and head a bit further this weekend, great weather promisedfor Saturdayat my locations. Will probably hit the borderline between brown and yellow, approximately 40 minutes of driving in one direction.

For the milky way project I could realistically hit a dark green area without staying somewhere overnight, but then we are talking 100 kilometers in one direction. Blue area? maybe never. But of course, if good weather is promised "for sure" I could drive 200 kilometers, have a good look, and then stayat a hotel overnight before driving home. We are then talking weekends, moon away, weather, motivation optimal. Looking a bit closer I couldeven get to agrey area with nearly the same effort, so why not, just some tens of kilometers more? Maybe drive there at Friday afternoon, heading back at Sunday, two great observing nights...

Bingo, nice hostel approximately 20 kilometers from the potential site, we'll see...

cormuresa

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Re: Light pollution maps
« Reply #14 on: January 15, 2018, 04:49:26 PM »
Quote
Think I will take a bit ofthe advice here and head a bit further this weekend, great weather promisedfor Saturdayat my locations. Will probably hit the borderline between brown and yellow, approximately 40 minutes of driving in one direction.

For the milky way project I could realistically hit a dark green area without staying somewhere overnight, but then we are talking 100 kilometers in one direction. Blue area? maybe never. But of course, if good weather is promised "for sure" I could drive 200 kilometers, have a good look, and then stayat a hotel overnight before driving home. We are then talking weekends, moon away, weather, motivation optimal. Looking a bit closer I couldeven get to agrey area with nearly the same effort, so why not, just some tens of kilometers more? Maybe drive there at Friday afternoon, heading back at Sunday, two great observing nights...

Bingo, nice hostel approximately 20 kilometers from the potential site, we'll see...

If by "Green" you mean something along the lines of a Bortle 4 or 5, that's similar to my area, so you'll definitely be able to see the milky way on a good night directly overhead. You probably won't be able to see anything faint at the horizon, depending on how bad the domes are around you and what direction they're in. A true grey site will make a world of difference. M42, M31, etc are pretty obvious naked eye objects from my back yard even on an "so-so" night.

You're definitely on the right track though with traveling. Even having it a bit better than some I try to get to the darkest sites I can whenever possible. It's always somewhat surprising to me how many people have been in fairly dark areas and didn't bother to look up at night. Instead they stay inside and watch TV or something - pretty ridiculous in my opinion.

I'm currently in the market for something (other than binoculars) I can pack into a really remote area - say, a couple days' hike in Wyoming, maybe with a pack horse. My dobs won't exactly fit that bill. I could possibly pull a trip like that off once every couple of years - but it'd totally be worth it.