Sky Glow (or sky glow), is a form of light pollution visible at night as a dome of light over cities and towns. It is caused by a combination of 3% to 10% of light reflected from the ground and other surfaces, and 90+ percent by lights shining directly into the air from badly designed or poorly installed lighting fixtures.  Because there is no safety or other reason to light up the air above our heads, sky glow is 100% wasted energy.

The map at the right shows the sky glow over southern Saskatchewan.

While sky glow cannot be entirely eliminated, reflected light can be reduced, and unshielded or misdirected light can be virtually eliminated.



Energy Waste 

The use of unshielded or poorly pointed lights, or using excessive amounts of light (over-illumination), wastes enormous amounts of energy in that there is absolutely no benefit to a 'light dome' although it costs just as much to light the sky as it does the ground. Where coal is used to generate power, as it is in Saskatchewan, thousands of tonnes of pollutants, including CO2, are released into the atmosphere annually for no reason whatsoever, harming not only the environment, but burning up millions of dollars in the process. 

Neither federal nor provincial governments have any plans to encourage good lighting practices. Fortunately, many cities are beginning to 'see the light' and realize the money to be saved through the use of proper lighting.   
Skyglow Map background courtesy of: P. Cinzano, F. Falchi (University of Padova), C. D. Elvidge (NOAA National Geophysical Data Center, Boulder). Copyright Royal Astronomical Society. Reproduced from the Monthly Notices of the RAS by permission of Blackwell Science.  ( Link = www.lightpollution.it/dmsp)
Myth: Sky Glow is an Urban problem 

The argument is often made that if you want dark skies, get out of town.  The map below gives shows the fallacy of this argument, as it may be almost impossible to find a sky in this 'Land of Living Skies' that is unaffected.  RASC Saskatoon member Tenho Tuomi  ventured out his door into what one would think to be a pretty pristine site north of Lucky Lake, and came up with photos of four light domes, each more than 100 kilometers away.
Click on each of Saskatoon, Regina / Moose Jaw and Swift Current below for the photos.   
While the sky glow in the photos here is made more evident by clouds, it of course exists, and is no less damaging to sky clarity, in cloudless skies. 
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