"ANYBODY got a BB gun?"
Outside the Montgomery College Planetarium after a recent Saturday night lecture, a nearby streetlight was giving the small group clustered around a telescope an introduction to light pollution as well as planetary observation.
The two often go together. That's one reason so many planetarium programs, like Sean O'Brien's "The Stars Tonight" at the National Air and Space Museum, begin with a comparison of how the night sky looks in or near cities and how it looks in the country. When he darkens the sky the audience gasps as the stars overhead snap into vivid relief.
The contrast isn't so stark in other parts of the country. In cities like Flagstaff, Ariz., where astronomy plays a more important role in the local economy -- it's home to several observatories, including the Lowell Observatory, best known for the discovery of Pluto -- light pollution ordinances make it possible to get a better look at the stars. "The sky in downtown Flagstaff is darker than anywhere within a three-hour drive of Washington, D.C.," the U.S. Naval Observatory's Geoff Chester says.
Light pollution doesn't mean there's too much light; it means there's too much light shining upward, where it's not needed. Most of it is produced by county and city lighting, and can be significantly reduced by adopting simple measures like switching to fluorescent or low-pressure sodium bulbs and using shielded, mirrored fixtures that direct light at the ground.
Such changes do more than make astronomers happy. "Most people don't realize that we could save an enormous amount of energy -- and money -- if we used the right kind of light," says Chester. In Tucson, where there is also a cluster of major observatories, a city retrofit of the lighting system paid for itself in three years. (The International Dark Sky Association is, not coincidentally, headquartered there.)
To the consternation of the Washington area astronomy community, legislative budget cuts in Virginia recently barred nighttime access to one of the area's darkest observing sites: Sky Meadows State Park in Delaplane. Organizers hope to relocate the park's popular star parties, which drew as many as 600 people. "Finding another place that even comes close will be difficult," says O'Brien.
So, what's a local stargazer to do? Montgomery College Planetarium director Harold Williams recommends a trip to Little Bennet Park near Clarksburg. "It's the last place in Montgomery County where you can see the Milky Way," he says.
For more information on light pollution and what you can do about it, go to www.darksky.org or www.enlightenmaryland.org.
-- Nicole Arthur