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Earth Space

Help Map Global Light Pollution, By Starlight 148

Posted by timothy
from the can-you-see-below-the-belt? dept.
Kilrah_il writes "Light pollution is a big problem these days, affecting not only astronomers and wild life, but also everyone else because of wasted energy. GLOBE at Night aims to raise awareness by urging people to go outside and find out how much light pollution there is in their area. 'The campaign is easy and fun to do. First, you match the appearance of the constellation Orion in the first campaign (and Leo or Crux in the second campaign) with simple star maps of progressively fainter stars found. Then you submit your measurements, including the date, time, and location of your comparison. After all the campaign's observations are submitted, the project's organizers release a map of light-pollution levels worldwide.'"
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Help Map Global Light Pollution, By Starlight

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  • by Iskender (1040286) on Wednesday March 23, 2011 @03:24AM (#35583546)

    This subject is clearly driven by astronomers with a desire to view the night sky. The issue of wasted energy seems only to be mentioned to gather support. This is clear in the first article which suggests using a 'shade' to make street lamps more efficient. A reflector is necessary if you want to get more useful energy out, as an opaque shade will just make your lamp housing hotter. I believe that modern designs do include reflectors now.

    It doesn't really matter why astronomers say what they say. What matters is if it's true. And there is no doubt that illuminating the sky directly is a waste of electricity and therefore money. If they advocate less than stellar solutions then the answer is to get better solutions, not to ignore the whole light pollution issue.

    The biggest issue being overlooked here seems to be what happens to the light that shines down as intended. This light reflects off things sending light upwards regardless of the lamp design. If you look at the aerial motor race photograph linked below you will notice that most of the light seems to be coming from the track itself, not the lights.
    http://www.craigfergusonimages.com/2009/11/aerial-f1-singapore-at-night-by-wong-kin-leong/ [craigfergusonimages.com]

    I don't think anyone is overlooking that. If you look, I doubt you can find many who say "We should eliminate ALL light pollution from urban areas". That's not happening, and everyone knows it. Astronomers accept the lesser bad of reflected light, and strive towards that rather than some improbable utopia.

    There's another thing too: light pollution is rarely created above light fixtures (which is where the picture is taken from), but to the side. Streetlights mostly light pollute in the near horizontal, meaning they tend to light pollute some distance away from themselves. If the camera actually was in the line of sight of the light sources (like people on the ground, or the sky when floodlights point at it) then the picture would be so full of camera flare that it wouldn't look even half as pretty.

    To sum up: reflected light is a problem, but it's nothing at all like what we have now, so people who care would be happy to deal with it instead.

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