This panorama shows light levels in the night sky over Walnut Canyon National Monument, Arizona. Although Flagstaff, population 75,000, is evident to the west, the sky is much darker than would normally be expected given the town’s proximity and population. A coalition of observatories, government agencies, private companies, and the public has enacted lighting ordinances and retrofitted many outdoor fixtures to improve lighting efficiency. Scientific records like this are useful for tracking mitigation efforts and encouraging public support to preserve dark night skies.

Experiencing a night sky filled with a blanket of stars becomes increasingly difficult at national parks. The growing populations in the western United States and the spread of development into rural areas have made light pollution a significant management issue for the National Park Service. In 2002 the NPS Night Sky Team, composed of park scientists and managers, continued efforts to monitor and preserve dark night skies, focusing on strategies to address impediments to protection. Obstacles within the Park Service include a lack of awareness of light pollution as a threat to wilderness values and cultural heritage, an absence of baseline information about this resource, and inefficient facility lighting.

The team tackled the awareness problem with an outreach effort to park managers and the public. Research presented at a conference cohosted by the Night Sky Team demonstrates that artificial night lighting not only diminishes the visitor experience but also has ecological consequences, influencing the behavior, biology, and survival of animals. A National Public Radio program examined endangered night skies in national parks, and a special issue of the George Wright Forum, edited by Joe Sovick, chief of recreation and partnerships for the Intermountain Region, received widespread attention.

Collecting baseline inventories for several parks represented a major effort in 2002. Astronomers at the U.S. Naval Observatory and the Lowell Observatory (both in Flagstaff) provided invaluable assistance with the development of research methods. More than 40 data sets now cover many southwestern parks. Preliminary analysis of the data shows that near-pristine skies can be found in those areas farthest from major cities and describes impairment caused by light pollution sources. For example, data from Walnut Canyon National Monument, 8 miles from Flagstaff, Arizona, indicate that although light from the city obviously causes light pollution, the night sky is far darker than would be expected (see image). The community has adopted lighting ordinances and retrofitted many outdoor lights. Scientifically sound information is vital for tracking mitigation efforts and encouraging public support. In 2003 the Night Sky Team will expand efforts nationwide and seed individual inventory and monitoring networks with “satellite” night sky teams.

last updated 4/14/2004