Light Pollution It is an unfortunate fact of today's life that most people are growing up in urban areas, unable to see the starry night sky that our grandparents knew so well. The prime night sky exists only in pictures or at a planetarium. This is true not only in cities but also in suburbs and in rural areas where street lamps and other sources of "light pollution" have obscured our view of constellations, meteor showers, and even the planets. This sky glow also represents inefficient use of electrical energy. Image Courtesy :

What You Are Missing & Wasted energy, you pay for: Inefficient and misdirected lighting costs the United States over $1.5 billion annually. Many lights shine 30% or more of their light into the sky, not where it is needed. The other part of the problem is that many commonly used lights do not effectively convert electricity to light, causing part of the problem. Sky view from Denver vs. From the mountains Image courtesy Note how many unshielded lights can be seen in this aerial view of an urban area

Inefficient vs. Efficient Lighting Inefficient Lighting These light fittings all have cut-off designs. No light is wasted, and no light escapes above the horizontal. Efficient Lighting These inefficient lights have rounded bowls which shine light in no specific direction; they even shine light above the horizontal! Images courtesy

What You Can Do Photograph © Cindy and Dan Duriscoe Set an Example o Switch off your lights when not in use o Install/retrofit lights with hoods that limit uplighting and use energy efficient bulbs o Join the International Dark Sky Association o o Become active with the Colorado Section of the IDA o Check out to find out howwww.du.edu/~rstencel/ida o Be Proactive! o Does your town have a lighting regulation? Ask. o Considering how the electricity is generated, many trades can influence choices toward smarter lighting: architects, developers, electricians, builders, planners, as well as astronomy enthusiasts

International Dark Sky Association Residential Lighting Choice Examples Flood Light Shield Porch Light Shields Colorado Section of IDA