Promoting Efficient Outdoor Lighting

(and saving the night sky!)

This is a recent (1992) NOAA composite satellite photo of the US at night:

Can you find your city or town? What's wrong with this picture? Why do we spend money and expend energy to generate light so that we may see at night, only to beam a large fraction of it into space? From satellite images such as this one, it is estimated that 30% of all outdoor light generated in the US is beamed toward the sky - completely wasted. The Globe at Night webpage makes the entire case (problems, solutions); I provide similar information below...

Back down on the Earth.... Glare defeats both safety  and security.

Indiscriminately beamed light is costly: in most  of the above instances, a properly shielded light bulb emitting fewer lumens would do the same job as a brighter but improperly shielded bulb. The long-term savings in money and energy demands are obvious.

We are losing the wonders of nature's night sky to wasteful, inefficient outdoor lighting. Fewer and fewer people experience a starlit night sky because it is flooded with wasted light. This sad story has been quantified and documented in this paper. How often have humans been inspired by the multitudes of stars in our Milky Way? What's up there? Where did it all come from? Where did we come from? Are we alone?... Should we take from our children this gift of nature?

Efficient outdoor lighting is a win/win proposition for everyone. It is also available, and becoming more so with increasing numbers of manufacturers (e.g., Hubbell Lighting, Green Earth Lighting, and Rabb Lighting). Many communities are adopting efficient lighting -  the cities of Los Angeles and Melbourne, Australia have replaced all of their street lights with full cut-off lighting. Here are links to state (e.g., Connecticut) & local outdoor lighting laws/ordinances. Here's an Outdoor Lighting Code Handbook. With the increasing costs associated with generating power (e.g., building new power plants, generation of green house gases), power companies are beginning to see the advantanges of efficient outdoor lighting. Everyone wins.

Here are some (1, 2, 3) short introductions to the problem of light pollution and its solutions.

Additional information may be found at the web pages of the International Dark Sky Association , its Michigan Chapter, and the New England Light Pollution Advisory Group.

1If this term is unfamiliar to you, think about where you point a flashlight when walking in the dark - at the ground away from your eyes. A flashlight pointed in the direction of your face produces glare, disabling you from seeing your surroundings.
2IESNA, Illuminating Engineering Society of North America

Kirk T. Korista
Professor of Astronomy
Department of Physics
Western Michigan University
Last edited: 17 March, 2009