By J. Celia Apodaca Geck

It's called "light pollution," and besides robbing residents of an unobscured view of the heavens, it costs the city of Las Cruces almost $500,000 a year.

That's the opinion of John Gilkison, chairman of the Light Pollution Committee of the Las Cruces Astronomical Society, And things will likely get brighter before they get darker -- which is bad news for the celestial-minded.

"The growth in population and increase in unshielded outdoor night lighting in this country has been eroding what was once a nearly pristine, dark, star-filled nighttime sky," Gilkison said.

The erosion of clear views is often counterproductive to area safety and security, is costly, generates unnecessary contention between neighbors and greatly diminishes aesthetic and scientific views of a star lit night.

"The loss of stars from the sky is tragic," Gilkison said. "Not one child in 10 has really seen the stars."

The stars are, of course, still out there. But our ability to view them is being destroyed by glare, light trespass and waste from inefficient outdoor lighting, Gilkison said.

Light pollution is graphically revealed in nighttime photographs of the Earth. Las Cruces appears as a small dot of light dwarfed by the larger El Paso/Juarez dot and even larger dots from urban centers such as Los Angeles and cities on the East Coast.

But even the small dots such as Las Cruces are visible from 30 to 40 miles away.

In an attempt to curb light pollution, Gilkison and the Astronomical Society are urging the city to adopt a lighting ordinance.

At an April 27 City Council work session, society members presented photographs and slides showing the best and worst lighting in the city.

Kurt S. J. Anderson, a professor of astronomy at New Mexico State University and site director for the Apache Point Observatory at Sunspot, spoke on behalf of the ordinance.

Anderson noted that even Apache Peak, high in the Sacramento Mountains, is in danger of being rendered ineffective by glare.

The entire astronomical industry in New Mexico also is threatened by the growing "light bubbles" above New Mexico's cities and some rural areas.

The provisions of the ordinance would apply to all outdoor lighting within the city limits, regardless of use or purpose. Advertising signs, billboards, use of lasers and searchlights and lighting of gas stations and convenience stores would be subject to the ordinance.

Lighting and periods of illumination for sports facilities, parking lots and other large outdoor facilities also will be addressed by the lighting ordinance.

Homeowners who have endured light streaming in bedroom windows from their neighbor's ill-placed lights will be able to seek relief through the ordinance.

Gilkison said that complying with the ordinance does not have to be expensive and can actually save money.

Homeowners, through the use of proper shielding and cut-off angle (the maximum angle a floodlight should be allowed to point upward) for all outdoor lights, could comply with the ordinance at minimal expense, he said.

Gilkison said that up to 50 percent of the light coming from unshielded outdoor fixtures escapes directly into the sky. Many security lights are placed at such shallow angles that they are of little use.

"I have often seen unshielded or poorly shielded lights angled up to 90 degrees or more used to light up postage stamp-sized back yards," he said.

Other solutions could be installation of a shoe box or a flat-lens cobra-head fixture or a unit called the Hubbell Skycap which directs uniform and wide distribution of light on the ground where it is needed.

The Extraterritorial Zoning Authority recently adopted a similar light pollution ordinance for the five-mile area surrounding the city limits to reduce the impact of future growth and glare.

Lighting ordinances are becoming increasingly common. Tucson, Ariz., headquarters of the International Dark-Sky Association, has embraced a lighting ordinance.

Las Cruces Mayor Ruben Smith said he supports a lighting ordinance and directed the Community Development Department to "...move it along as quickly as possible."

Smith asked that normal procedures be followed, public input be solicited and several options be prepared for City Council review within two months.

He [Gilkison] is available for presentations -- complete with displays of effective and ineffective lighting -- to schools and other organizations.

Gilkison also teaches course on Beginning Stargazing and Observational Astronomy at Dona Ana Branch Community College and is presenter of the monthly Sky Safaris sponsored by the Natural History Museum.

The next Sky Safari is scheduled for 8 p.m. May 23 at La Llorona Park at the Picacho Avenue bridge crossing the Rio Grande.

Anyone interested in learning more about light pollution and its solutions can contact Gilkison at (505) 525-2689 or on the Internet at jgilkiso@nmsu.edu