The source of this sky glow is the thousands of outdoor lights that not only illuminate their target area, but their neighbor's yard and beyond. Figure 1 vividly demonstrates how wide spread the problem is. Some of this light is of course necessary for safety and security, but to say that there is room for improvement would be an understatement. Correcting the bad lighting practices of the past will certainly make star gazers happy, yet it is the public that will reap the greatest benefits through glare and light trespass reduction.

Most bad lighting is the result of lack of awareness. You wouldn't even think of dumping your used motor oil down a sewage drain, but putting up a security light that lights up your yard is a no brainer. I'd be the first to admit that finding good lighting fixtures at WalMart or Lowes that do not light up the neighborhood can be a bit challenging. Manufactures are part of the problem. They are catching on though. There are shields, such as the Hubbell SkyCap (see figure 2), and good fixtures like Regent Lighting's RSM 100, which is available at local building supply stores.

Locally, there has been lots of good news. Washington D.C. has started to convert over their antiquated street lighting with the full cutoff type, which do not emit any light directly above the horizontal. The state of Maryland will do the same for state owned roadways. The lighting for the expansion of the northwestern section of the Baltimore Beltway is a fine example of this policy. Lighting ordinances have been passed or are being considered in Fauquier County, VA, Loundoun County, VA and Gaithersburg, MD. A dark-sky preserve is in the works for northern Baltimore County, MD. Here's a few links that you can check out to see how you can help improve our nighttime environment or find a dark observing locale near you: International Dark-Sky Assoc. (IDA): http://www.darksky.org DarkSky web tool: http://www.darksky.org/ida/darksky

Forrest Hamilton

(Submitted: 3/29/2000)