Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Jan 24, 2012, 14:47:20

Title: Google Earth light pollution map - France/SE England
Post by: MarkS on Jan 24, 2012, 14:47:20

Last month (Dec 2011) Frederic Tapissier released his newly updated light pollution map for France.  A great resource for anyone thinking of going imaging in France ;-)

It also covers SE England and best of all, it works in Google Earth.

Quick preview here:
http://www.markshelley.co.uk/webdisk/light_pollution_preview.jpg

To use it you need Google Earth installed and then pick up the "kmz" file referenced here.
http://www.avex-asso.org/dossiers/wordpress/?page_id=38#ge

Mark
Title: Re: Google Earth light pollution map - France/SE England
Post by: Mike on Jan 24, 2012, 14:58:12
has anyone been to that Norwood Farm yet?
Title: Re: Google Earth light pollution map - France/SE England
Post by: MarkS on Jan 24, 2012, 15:09:48

I camped there one weekend.  Very dark sky but the toilet block had very bright lights which intruded over the whole site.

The lights will be switched off for the Dymchurch Star Party in April, so it ought to be pretty good.
http://dymchurchstarparty.webs.com/

Mark
Title: Re: Google Earth light pollution map - France/SE England
Post by: mickw on Jan 24, 2012, 15:16:07
There is another downside to Norwood Farm, there's a miserable git about 1.5 miles SE that has laser pointers and a box of khoom fayes  :twisted:

Note to self:  Order another 2 boxes of khoom fayes  :angel:
Title: Re: Google Earth light pollution map - France/SE England
Post by: MarkS on Jan 24, 2012, 22:11:46

I've just found that he has a map covering the whole UK:
http://www.avex-asso.org/dossiers/wordpress/?page_id=127

The map is created using an algorithm.  However, he does admit that the light pollution for some smaller villages is not always assigned correctly to source - in other words the light from some smaller villages does not appear even though it should.
Title: Re: Google Earth light pollution map - France/SE England
Post by: mickw on Jan 25, 2012, 10:57:28
That's the version I've been using and it isn't so detailed either.

The new version also shows LP on the roads
Title: Re: Google Earth light pollution map - France/SE England
Post by: MarkS on Jan 25, 2012, 11:09:08
Quote from: mickw
The new version also shows LP on the roads

The LP on the roads is a bit of informed guesswork, really.  His approach is to model the observed light pollution back to its supposed sources - centres of population and roads.  But it's not always correct - for instance Dungeness Power Station is conspicuous by its absence.  And some villages are missing.

I still prefer the original DMSP data - the kmz file for Google Earth can be downloaded from here:
http://www.ngdc.noaa.gov/dmsp/maps.html
Look for "DMSP OLS Global Composites Version 4"  - it contains the true observed LP data from satellites for years up to and including 2009.

Mark
Title: Re: Google Earth light pollution map - France/SE England
Post by: Mac on Jan 25, 2012, 12:44:23
Just loaded his map on to google earth,
He shows Nyewood as having light polution,
Im assuming he has surmised that all villages have streetlights.

Going to do a compare to the true light polution map and see the differences.

Mac