Sunday, Mar 26, 2006
Washington, D.C. --- Light pollution, unwanted artificial light from outdoor lights can substantially affect the views of the night sky. In some areas of the country, the skies can be bathed with a wash of sky glow from outdoor lights. Lights that shine upward, sideways, or are too bright, are scattered through the atmosphere and are visible from distant landscapes, at times making the night sky seem washed out.
The National Park Service (NPS) today released data collected by scientists who have been studying the effect of light pollution upon starry skies. This is the first comprehensive data set of its kind. Using a high-resolution astronomical-grade digital camera, the sky at several national parks was captured, enabling precise measurements of the amount of light in the night.
"We have adapted the methods of astronomical photometry of stars to create images that accurately measure the background brightness of the entire sky. In this manner we can calculate precisely just how much artificial light shines down into our parks," said NPS investigator Dan Duriscoe. ?This enables the National Park Service to track light pollution.?
The images, shown in panoramic and ?fish-eye? format, clearly show light from cities near and far brightening the night sky above national parks. False color is used to enhance the contrast of both natural and artificial features of the sky. ?At every park we have surveyed, we have detected artificial light,? said Chad Moore, co-investigator and manager of the NPS night sky team. Pristine night skies were once commonplace just a few decades ago, but have become increasingly rare under the advance of glary lights.
As over lit skies become the norm, park visitors have come to seek out star-filled skies. Many of the best night skies are still found within our national parks. Visitors are increasingly seeking out dark skies in places like national parks to rediscover the beauty of the night sky. ?By sharing our telescopes and enthusiasm for the night, we help them celebrate that beauty,? said Kevin Poe, park ranger at Bryce Canyon National Park, where stargazing programs were attended by 27,000 people last year.
Light pollution may also be a problem for nocturnal species. The current issue of Science News magazine links artificial light to changes in animal behavior and survival. The measurement of light pollution and sky quality is part of a comprehensive effort by the NPS to inventory park resources in order to track park health and provide quality experiences for visitors.
National parks are starting the process of retrofitting their outdoor lighting to use night sky friendly ?shielded? lights and lights that use less energy. A four-year project was just approved to direct revenue from park fees toward improving park lighting in several national parks. This is the first step in restoring the night sky. ?We hope that tomorrow?s children will be able to come to parks and gaze upon the cosmos, be inspired, and enjoy the same view our parents once had in their backyard,? remarked Moore.
For images and information on National Park Service efforts to manage natural lightscapes visit: http://www2.nature.nps.gov/air/lightscapes
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