[SQM] ecological light pollution paper, and worldwide SQM database

Andrew Cool andrew at cool.id.au
Thu Mar 3 20:52:50 UTC 2011

Hello Christopher,

You say :-

"This indicates that the cloud amplification factor depends upon local
 (maybe it's a nice function of population density?)..."

You may be interested in this site, where I model Light Pollution around
South Australia using Walker's Law using population by postcode areas :-

As you can see, it matches the output from CinZano's Light Pollution Atlas
quite well.

And closer to home for you, all of Germany :-


I do not have the necessary population figures for the countries surrounding
So this map does not take into account Light Pollution from population
centers in other countries
That lie close to the German border.

Neither do I have the skills in mathematics to relate the values returned
from Walker's Law back
To mag per square arcsec, or candelas per Rudolph's Nose or whatever the
appropriate metric might be.

However, it is clear that Berlin is not a good place in which to do
The Brocken looks better as does the Lueneberg heath area. 

If there is any interest in generating similar maps for other countries, all
I need is a file
Of post code areas, the centroid point for each post code area, and the
population per postcode area.
The Germans were most efficient in being able to provide all this in one
flat ASCII file.


Andrew Cool

-----Original Message-----
From: sqm-bounces at unihedron.com [mailto:sqm-bounces at unihedron.com] On Behalf
Of Christopher Kyba
Sent: Friday, 4 March 2011 12:39 AM
To: Chuck Bueter
Cc: sqm at unihedron.com
Subject: Re: [SQM] ecological light pollution paper,and worldwide SQM

Hi Chuck,

Thanks for your email, and especially sharing the data!  If I put our
results in the same table, and re-arrange by clear sky brightness:

Location                Clear   Cloudy

Rural Berlin            21.0    19.9      <- Europe
Madison                 20.23   18.86
Grissom                 19.47   17.50
Horizon                 19.32   17.58
Discovery               19.23   17.39
Free University         19.0    16.5     <- Europe
Prairie Vista           18.71   16.41
Elsie Rogers            18.63   16.88
Walt Disney             18.12   16.30

You can see the results aren't monotonic.  See the attached plot that shows
the amplification factor for each site - the Berlin sites have an "x" inside
the "o".

This indicates that the cloud amplification factor depends upon local
factors (maybe it's a nice function of population density?), and it shows
why we need to repeat the cloud amplification study but using diverse


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