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Wednesday, 29 August 2007 00:00

Keep me in the dark

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Scott McLeod, my editor, tossed an Aug. 20, 2007, New Yorker on his desk and said there was a good article about light pollution in it and wondered if I was interested. I was. But I’m sure that doesn’t come as a surprise to many Smoky Mountain News readers who think McLeod and I are in the dark about a lot of things.

The article, by David Owen, points out how most of the civilized world is losing touch with half of the universe – the dark side. Owen notes that a visitor to the observation deck of the Empire State Building, on a dark night, would see less than 1 percent of the celestial objects that Galileo would have gazed upon with his naked eyes.

According to the Bortle Dark-Sky Scale, a 10-point system (with Class 1 the darkest) devised in 2001 by astronomer John E. Bortle, New York City is a Class 9. Most of America suburbia ranks from Class 5 to Class 7. One would be hard pressed to find any spot in the U.S. darker than Class 2. Owen notes that if one were standing on the North Rim of the Grand Canyon on a moonless night the brightest feature in the night sky would be the glow from Las Vegas 175 miles away. I remember, years ago, crossing the Chihuahan Desert on I-40 and pondering a glow in the night sky for a couple of hours only to discover it was Albuquerque.

The article talks about the International Dark-Sky Association. Astronomer David L. Crawford co-created the IDA in 1988. Crawford began his career as an astronomer at Kitt Peak Observatory near Tucson, Ariz., in 1958. By 1970, he had noticed a loss in astronomical visibility at the observatory.

Crawford and the IDA believe we could regain much of that loss astronomical visibility and, according to IDA’s mission statement, “... preserve and protect the nighttime environment and our heritage of dark skies through quality outdoor lighting.”

The IDA and others who study light pollution call most of traditional outdoor lighting fixtures glare bombs — those fixtures cast most of their light sideways and/or up into the heavens. The simply remedy are fixtures known as “full cutoff” or “fully shielded.” The fixtures cast no light above the horizontal plane and the light source is not visible from the side. Full cutoff fixtures are no more expensive than glare bombs and they are much more economical to operate. According to Owen, Calgary, Alberta, reduced its electric bill by $2 million a year by replacing all its street light with low-wattage, full cutoff fixtures.

And aliens won’t need a road map to find us. Owen notes that if one installed a basic wall pack (common outdoor fixtures) on the moon and pointed it towards earth it would be visible, “...when it wasn’t itself in direct sunlight, with a moderately powerful hobbyist’s telescope.” H’mmm, maybe all those UFOs are just giant space insects attracted to the lights?

According to IDA’s website, www.darksky.org/, adverse effects of light pollution include:

n Energy waste and the air and water pollution caused by energy waste

n Harm to human health

n Harm to nocturnal wildlife and ecosystems

n Reduced safety and security

n Reduced visibility at night

n Poor nighttime ambiance

Owen points out what a bane outdoor lighting is to sea turtle populations. Mother Nature made it easy for baby turtles to find home — they would just poke their heads out of the sand and crawl to the light, which, before Edison, would be the ocean. Now they head for the mall.

My fellow surveyors at the offshore survey company I worked for in Louisiana thought me a bit strange because I always volunteered for any points on abandoned, unlit platforms in the Gulf. But lying on the heliport, at night, in my sleeping bag was like being enveloped by the galaxy.

I don’t know about McLeod, but as far as I’m concerned, keep me in the dark – please!

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