Light Pollution
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Light Pollution map for Lubbock and the surrounding area.

 Composite map (full-size)      Original image from the Clear Sky Clock.
Black = Excellent dark skies 
Blue = Dark - Levels visible in Milky Way
Green = Milky Way just visible
Yellow = Milky Way not visible
Red = Some bright stars visible
White = Only planets and moon visible 

I created these maps by merging a Map Point map with the light pollution image found at the Clear Sky Clock.  I got the idea for this map from this page, which is the originator of the scale that accompanies the CSC map.  Thanks to the angle of the orbital images, the light pollution image is not strictly to scale, but rather is compressed in height or width.  So you need to stretch and adjust the image to match the map.  The merging isn't too difficult, if you're familiar with Photoshop, but the adjustments in size or scale can be tedious.

So what does all this mean?  If you can see the street lamp from orbit or an airplane, this is light that serves no useful purpose and wastes light.  These maps show direct light visible from orbit and are a measure of wasted energy in our urban environment.

Where does this light originate?  Any light that's visible from a airplane or from orbit is wasted.  The primary source of this light is the security and street lighting fixtures with large glass globes:

        
Images from Choptank Electric http://www.choptankelectric.com/meminfo/lighting.html

The light that goes upward or excessively outward is not useful and is simply wasted.  Worse, it can actually decrease the usefulness of the light by increasing the glare in the area.  The two most common lamps can be greatly improved with the addition of inexpensive reflector-shields:
   
Not only will these shields prevent light pollution, but they can also give significant energy savings.  Accorded to common statistics, the bad fixtures waste 30% or more of the produced light.  These shields would allow the owner to use a lower wattage lamp that would use less power to produce the same amount of light.