When was the last time you saw the night sky revealed, with its full array of stars? Some New Mexicans living in remote areas can see the cosmos in all their glory every night, clouds permitting. But those living in population centers, including many small towns, cannot, due to artificial lighting.
Unlike many states, New Mexico has a state law limiting light pollution. However, Jon Holzman, an astronomy professor at New Mexico State University, said that the 1999 New Mexico Night Sky Protection Act is due for an update, thanks to changes in light-bulb technology. More on that in a bit.
Holzman spends some of his personal time working for DarkSky International, an organization focused on preserving the world’s unspoiled night skies.
“Only a small fraction of the U.S. population lives somewhere where they can even see the Milky Way, so people don't even know what it is,” Holzman said. “And people are starting to come to darker locations for a new kind of tourism called astro-tourism, and New Mexico is a good destination for that. So it actually brings in some economic impact by preserving our dark skies.”
However, tourist dollars are far from the most compelling reason to protect dark skies. The unblemished night skies are important for migrating birds. Holzman said humans benefit, as well.
“There's some suggestion that light pollution affects human health,” Holzman said. “And then there's also the simple argument of energy and money. Putting light up in the sky where it's not used wastes energy and costs extra money.”
DarkSky advocates for lighting to go only where it’s useful or necessary.
“I think it's important to state up front that the goal of organizations like DarkSky is not to have everyone turn out all their lights,” Holzman said. “It's to do what we call responsible lighting. So when lights are installed, the light shines on the ground where it's needed, and not up in the sky where it just does no one any good and it does a lot of harm.”
New Mexico DarkSky has been an active chapter of the international organization since June 2023. But that state’s legislation protecting dark skies was written when incandescent lighting was the norm.
“Now the predominant type of lighting is LED lighting,” Holzman said. “And people used to talk about how bright lights were in terms of watts, which is a measurement of energy, not a measurement of brightness.”
Energy-efficient LED lighting uses fewer watts, so intensely bright lights can fall well within the now-archaic wattage restrictions. New Mexico DarkSky seeks to get the New Mexico statute to limit lumens, rather than watts.
Although DarkSky does lobby for legislation, the organization’s main focus is education and outreach among the general public, Holzman said. DarkSky offers resources for homeowners, businesses and public agencies looking to make their lighting more night-sky friendly.
“The basic principle is, use shielded lighting outside, so that you're basically ensuring that any light fixtures that you put up don't put any light up in the sky and don't put any light into your neighbor's yards,” Holzman said.
“Sometimes excessively bright light can create excessively dark shadows, which people can go unseen on and if you're looking outside, or law enforcement is looking outside, bright lights can actually blind you, in a process we call glare … it's hard to see an intruder when there's extra glare,” Holzman said. “So responsible lighting can actually be safer.”
For domestic needs, Holzman recommends setting outdoor lights to motion sensors, when possible and where appropriate.
New Mexico DarkSky has joined with several public and private entities to form the Dark for the Park Alliance, a collaborative effort to preserve dark skies in the vicinity of Carlsbad Caverns National Park in the state’s southeast, and Chaco Culture National Heritage Park in northwestern New Mexico.
In Carlsbad earlier this year, Denver-based Franklin Mountain Energy retrofitted a production site, with the result of a 99 percent reduction in skyglow, or the appearance of brightness in the night sky. The changes also reduced the lighting system’s electricity consumption by 60 percent, the company said.
Light-pollution mapping projects, such as this one published by University of Wisconsin researcher David Lorenz, show the dramatic effects of oil and gas production on night skies in the Permian Basin.
DarkSky also has a program for establishing recognized dark sky locations, with varying certifications for different types of sites. New Mexico currently has nine certified dark-sky locations, including the Gila National Forest’s Cosmic Campground, the only site in North America to earn the DarkSky International’s highest ranking, that of International Dark Sky Sanctuary.
In addition to conservation and awareness, Holzman also recommends just enjoying the beauty of a truly dark New Mexico sky, if you haven’t done so recently -- or ever.
“New Mexicans are lucky, and we should realize it,” Holzman said. “A lot of people in this country don't have what we have, so we should appreciate it, and we should preserve it.”
