Feature Article - September 2007
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Let There Be Dark

How Smart Lighting Design Increases Security, Performance and Night-Time Aesthetics

By Emily Tipping



Step by Step

If you're not working on a brand-new facility, you can still do a lot to address light pollution. Simple solutions, such as shielded fixtures that direct light downward to reduce glare, lower-wattage bulbs, motion detectors and more efficient lamps can make a big difference. And you don't even need to overhaul your entire site at once to make a difference.

As the NPS states on its own Web site, "Lighting retrofits can be relatively easy and inexpensive, and can also be accomplished on an individual basis. When a light blows out, it is a good opportunity to replace the bulb with a lower-intensity bulb or change the fixture to a full cut-off fixture, which directs all the used light downward. Retrofitting outdoor lighting not only helps restore the night sky, but also is environmentally friendly, energy-efficient and provides more security."

In one major project, the NPS modified over 80 percent of the fixtures in Natural Bridges National Monument, making them dark-sky-friendly. Most of the fixtures now use 13-watt compact fluorescent bulbs, which provide plenty of light but prevent stray light from buildings such as the visitors center and park ranger residences from interfering with campgrounds and backcountry.

The work paid off in April 2007, when Natural Bridges was named the world's first international dark-sky park by the IDA. The beauty of the night sky, the lack of light pollution and NPS' commitment to night skies as a natural resource helped the park earn the designation.

Ralph Jones, the park's chief ranger, said the monument is "one of the darkest national parks in the country."

Taking its dedication to the nighttime sky one step further than fixtures, the park has also dedicated itself to educating the public and sharing the beautiful vistas of night sky with at least some of the 100,000 people who visit each year. During the summer, visitors can take part in astronomy ranger programs. Other ways to "share the night" cited by the NPS include full moon walks and nocturnal wildlife viewing.

"Parks are great places to experience a natural lightscape, and the experience can be even more enjoyable with professional interpretation," the service reports.

The impact of the changes made at the park have spread beyond the stars. "Natural Bridges has reduced its operational costs and energy use by upgrading its outdoor lighting, creating a better habitat for nocturnal wildlife and improving visibility and safety at night," said Park Superintendent Corky Hays. "I hope our national parks can continue to provide a clear view of the heavens that so many of us have lost from our backyards."

Can't imagine doing things on such a grand scale? That's alright. As the saying goes, "Think globally, act locally." You can take the example of Natural Bridges and reduce the scale of the lighting overhaul to meet the needs of your own, smaller facility.

That's just what happened at Potawatami Wildlife Park, a nonprofit 320-acre preserve in Tippecanoe, Ind. Now recognized as Indiana's first Dark-Sky Preserve by the Indiana Council on Lighting Education, the IDA and the Indiana State Senate, the preserve only made minor changes to address light scatter.

The change was instigated when the current executive director, who is a member of the Warsaw Astronomical Society, invited members of the club to use the property in the mid-1990s. The parks' management understood the value of the observing opportunities and took steps to manage the site as a dark-sky preserve. Barnyard-style security lights were removed, and a shelter light was adapted with a shield to reduce glare. The only current dusk-to-dawn lighting on the property now is a fully shielded security fixture that lights the restroom area. Sofit lighting lines one sidewalk with minimal wattage, and a memorial is lit with two spot lights on a dimmer switch, so that only the three flags—not the sky—are illuminated. All of these lights are hooked up to a breaker panel that trips all exterior lighting when observing is conducted. In addition, the executive director's on-site residence employs blinds to reduce the impact of interior light on the outside environment, and includes an outdoor security light with a motion detector.