Well, it happened again. Relatives visiting from back East were astounded at our night sky. “I can’t believe how many stars there are! -I didn’t realize how beautiful the night sky is” have become common refrains. Living in the rural west we tend to take for granted our grand vistas and dark nights. We also tend to forget that the majority of Americans live in areas so blighted by artificial lighting that the night sky has disappeared. Unfortunately the problem is not confined to large population areas. Rural areas are increasingly impacted. A recent article in National Geographic (Nov 2008 ) entitled “Our Vanishing Night” highlighted this problem. 

Any outdoor light produces a phenomenon know as “sky glow”. The more outdoor light and air pollution - the more sky glow. Large cities and major transportation corridors produce a tremendous amount of sky glow and can affect areas for hundreds of miles. There are no places left in the continental United States with truly dark heavens. There is a generation of our children growing up that have never seen the Milky Way or more than a handful of bright stars. The brilliant display of thousands of stars set against a velvet black sky that our grandfathers slept under is being replaced by a dull artificial glow. John Wayne out on the lonesome trail - sleeping under the equivalent of a streetlight!

Currently the National Park Service has designated a few remote National Parks as “Dark Sky Sites”. A tourist business has emerged touting dark skies, catering to folks from light blighted areas. For communities dependent upon the outdoor tourist dollar, dark skies will become a rare and valuable asset, an asset that is too easily lost.

Early exterior lighting fixtures consisted of a bare incandescent bulb with a simple shield on top to keep the rain off. Only a fraction of the electricity used actually produced light, with the majority of the power spent heating the bulb. Of the light produced, only a fraction was beneficial since the majority of the light was wasted by shining upward and sideways. Improvements in bulb technology, including fluorescent and sodium vapor lamps, have improved the efficiency of the bulb itself., producing a better balance of light versus heat. However, the glass enclosure does nothing to utilize the light escaping upward.

The best solution for outdoor lighting today comes from innovation in design of the surrounding fixture rather than the bulb. The full cut-off outdoor fixture uses a highly reflective, specially shaped shield to reflect all the light produced by a bulb downward, utilizing the light that would otherwise be wasted. The full cut off outdoor light improves the overall efficiency and does the most to reduce unwanted sky glow.

Light is not free! As we enter the 21 st century, energy has become more expensive and will become even more so over time. Unwanted and wasted light is estimated to cost the United States more than 2 billion dollars out of the 11 billion spent on outdoor lighting each year.

The irony of the situation is that poorly designed lights are actually counter productive. Not only are they costly but by shining a bright light directly into peoples’ eyes, it actually makes it more difficult to see at night. Like an oncoming truck leaving the ‘brights’ on - a poorly shielded yard or street light hinders rather than helps night vision. The rationale for yard lights has been expanded to include security light, but that is a big city solution applied inappropriately to a rural problem. Rural outdoor lights left on all night provide little in the way of security and in fact may actually aid rather than impede theft or vandalism.

Here are a few questions we should ask the next time they pay the electric bill: What purpose does an outdoor light serve? Security, illumination, advertising, decoration? Would a smaller, more directed light serve your needs? For instance, installing a motion detector switch on lights used primarily for security has been shown to be much more effective in curtailing burglaries and vandalism than a light left burning all night long. Replacing a ‘light bomb on a pole’ with ground level lighting allows the human eye to better adapt to the dark-seeing more while using less energy. Most importantly, fully shielded full cut-off fixtures greatly increase your night-lighting ‘bang for the buck’. It makes dollars and sense to take advantage of that technology.

It is up to all of us, both in our own interests and for the good of the United States of America to be wise energy users. Help preserve what is left of the rural night skies before they too become just a memory. Dark night skies are part of what makes the rural West - the West.

About the author:
Marcus Honnecke has enjoyed the West's night skies from childhood. A fourth generation Colorado native, he and his wife live in North Park where they are members of Ranges and Rivers, a grassroots citizen organization promoting quality-of-life issues in Jackson County. He built his own observatory near his home and has taught astronomy to students of all ages for decades.