The new world atlas of artificial night sky brightness

[laser_jock99]

A new study has been released looking at the spread of Light Pollution.

http://advances.sciencemag.org/content/2/6/e1600377.full

One of their conclusions is that most of the UK is in the zone with furthest distance to travel to reach a pristine sky.

 

So according to the map above my skies in Mid Wales are in the Green Zone and are thus "degraded to the Zenith".

 

I'll just check outside....

(Spring Milky Way- May 2016 EDIT SQM reading 21.8 this night)

[estwing]

yeah rubbish in Elan.....pity theres not a dislike button for your post!..as the old advert used to say..."Scotland's for me!"

[estwing]

so in fact the best place to observe is in the Atlantic!...and how about those oil rigs!!!!!

[Martin Meredith]

I suspect you need to look at the detailed map as referenced on the other thread:

While some of their statements are perhaps overgeneralisations (distance to go), surely this kind of study is a step in the right direction. 

Martin

 

[laser_jock99]

I don't disagree with the study as whole, indeed it's all good as far as I'm concerned for highlighting the issues to policy makers and the general public. The data they have used is rather 'generalised' I'd say. As with all these LP maps the local conditions, as obsereved on the ground are what counts.

[DHEB]

12 minutes ago, laser_jock99 said:

I don't disagree with the study as whole, indeed it's all good as far as I'm concerned for highlighting the issues to policy makers and the general public. The data they have used is rather 'generalised' I'd say. As with all these LP maps the local conditions, as obsereved on the ground are what counts.

Exactly, there are side effects of the necessary generalization of data, that might render local light pollution meaningless. For detailed planning I prefer the Blue Marble, a series of mosaics of nightly satellite images, viewable in Google Maps. There are mosaics for several years. It is also very detailed. Very recommendable!

[Martin Meredith]

Thanks for the pointer to Blue Marble. The problem I see with those images is that they don't appear to allow one to distinguish between only quite good and truly excellent skies. According to the images, I live in a place with little or no LP; according to the model-based approach in the new atlas, I live in a yellow zone. In fact, the latter is much more in accordance with what I can see on the best nights (no winter milky way, for instance). The best SQM I've ever obtained is 20.6. 

So I see the Blue Marble as being good for telling me where definitely to avoid, and perhaps with a bit of mental averaging working out which places are furthest from the major sources of light shown on the map. With some post-processing (like log scaling), the Blue Marble might allow us to make these finer (but critical!) distinctions. 

What I like about the new atlas is that it is a well-justified scientific/peer-reviewed model with stated assumptions, whose predictions have been tested against SQM readings on the ground. It isn't perfect, but if you read the assumptions they mention in the discussion there is quite a degree of sophistication there, and like all such efforts, it serves as a building block for even better models.

Martin

[DHEB]

6 minutes ago, Martin Meredith said:

Thanks for the pointer to Blue Marble. The problem I see with those images is that they don't appear to allow one to distinguish between only quite good and truly excellent skies. According to the images, I live in a place with little or no LP; according to the model-based approach in the new atlas, I live in a yellow zone. In fact, the latter is much more in accordance with what I can see on the best nights (no winter milky way, for instance). The best SQM I've ever obtained is 20.6. 

So I see the Blue Marble as being good for telling me where definitely to avoid, and perhaps with a bit of mental averaging working out which places are furthest from the major sources of light shown on the map. With some post-processing (like log scaling), the Blue Marble might allow us to make these finer (but critical!) distinctions. 

What I like about the new atlas is that it is a well-justified scientific/peer-reviewed model with stated assumptions, whose predictions have been tested against SQM readings on the ground. It isn't perfect, but if you read the assumptions they mention in the discussion there is quite a degree of sophistication there, and like all such efforts, it serves as a building block for even better models.

Martin

I agree, both are good data products. I did not mean one to be better than the other. As you say, there is a degree of sophistication in the new maps that deserves attention and understanding. Blue Marble are just satellite images with comparatively little processing.

[laser_jock99]

I think the Avex light pollution map is still the most acurate indication of real world  conditions

Apparently it is based on population levels (IMHO population density is directly proportional to light pollution)

[DaveS]

It's made it onto the BBC site

http://www.bbc.co.uk/news/science-environment-36492596

I use this map quite a lot, as It's higher res than the Blue Marble one, and up to date. It also shows how LP has changed over the recent years

http://www.lightpollutionmap.info/#zoom=9&lat=6712584&lon=-56697&layers=0BTFFFF

There's also a new Avex map, though not quite so usable as the old one

http://avex-asso.org/dossiers/pl/europe-2016/google-map-fausse-couleur/index.html