Inside the McDonald Observatory’s Mission to Preserve the Darkest Skies in West Texas


Bill Wren remembers the night sky rising like wallpaper above him when he was a child in rural Missouri. But after a move to Houston in 1970 when he was 15, lights from the city’s sprawl obscured all but a few stars. It wasn’t until he was 21 years old, on a camping trip to West Texas’ Davis Mountains State Park, that he flashed back to the Missouri skies of his childhood. Staring at a starry mass running to the horizon, he realized constellations he commonly saw near cities were hard to discern in truly dark skies.

“Once you see them, you never forget them,” says Wren, who now spends his days trying to assure dark skies for campers and researchers in the area. As the Dark Skies Initiative coordinator, he stresses how good lighting results in business savings and worker safety at the 500-acre McDonald Observatory, located at 6,800 feet elevation, 111 miles north of Big Bend National Park. He also helps measure sky darkness in the area, using precise measurements of sky brightness and glare across the entire celestial hemisphere, identification of light pollution sources, separation of natural and human-caused sky brightness, and other National Park Service methods.

A research unit of The University of Texas at Austin, the observatory owns one of the world’s largest optical telescopes, the Hobby-Eberly, and works to maintain the Milky Way and other sky views for research and education. While views above “remain pristine,” Wren points out that these days astronomers are finding the need to build observatories in places far from city lights, such as Hawaii and Argentina’s Atacama Desert.

Since the 1970s, the McDonald Observatory has coordinated with seven surrounding counties to decrease glare, educating municipalities on lights that point down or are shielded and have amber hues instead of sharp whites. In 1978, the state legislature passed a bill giving nearby counties the option to adopt lighting ordinances. In 2011, Gov. Rick Perry signed House Bill 2857 to instruct nearby counties to adopt the ordinance. At this point, those counties make up 28,000 square miles (18 million acres) of lighting ordinances and dark skies. “It’s the largest area of the planet that I know of where night skies are protected,” Wren says.

Few places on Earth are as dark these days as when Wren was a child. As urban populations grow, 80 percent of people around the world cannot see the Milky Way from home and live under light-polluted skies, according to the 2016 scientific publication the New World Atlas of Artificial Night Sky Brightness.

Even surrounded by the West Texas desert, the McDonald Observatory now sees more illumination on its horizon. Since 2008, an increase in oil and gas operations in the Midland area has led to McDonald Observatory measuring more light emitted by that city’s growing population, businesses, and energy activity 172 miles to the northeast. While stars wink in pristine skies overhead, brightness gathers in trees on the observatory’s hills. “We’re shining wasted light into the night skies, and it has the potential to ruin our view,” Wren says.

It’s affecting our health, too. Light pollution affects human and animal circadian rhythms and creates more carbon emissions, according to 2007 and 2010 studies. In 2012, research showed too much artificial light can also influence animals’ behavioral changes in mating, movement, migration, communications, and mortality. Light pollution is increasing worldwide at a rate of 2 percent according to a 2017 analysis of satellite images. “If Van Gogh were alive today, would he be inspired to paint ‘Starry Night’ if he couldn’t see the sky?” Wren asks.

Good lighting practices make a difference. “This is about creating dark skies, not dark ground,” Wren says, and that the key to making conservation work is showing businesses how they benefit. In 2010, he and his team began reaching out to oil and gas companies and municipalities to demonstrate improved worker safety without glare and an average of 80 percent less power consumption when light is focused downward, allowing for lower wattage bulb use. “The kind of light that’s good for the business’ visibility at night also helps the night skies,” Wren says.

The Dark Sky Initiative’s work sped up in 2013 when Wren was introduced to Pioneer Energy Services, which provides land contract drilling. He visited drilling sites to assess light use, noticing at one rig that a worker’s operation console faced a bright white light. He had stuffed a rag on the casing to lower its glare. Wren learned the light manufacturer offered optional shields, and Pioneer incorporated them in all its rig designs. McDonald Observatory also worked with Apache Corporation to include good lighting practices in rigs near Balmorhea.

The McDonald Observatory’s recommended lighting practices guide is endorsed by the Permian Basin Petroleum Association, Texas Oil & Gas Association, and American Petroleum Institute. In February 2016, the Texas Railroad Commission, the state agency with primary regulatory jurisdiction over the oil and natural gas industry, first sent a notice to operations with the observatory’s guidelines, writing that “the solutions can be simple and cost effective and can actually improve nighttime visibility and increase worker safety.”

For its work, the McDonald Observatory received a Texan by Nature 2018 award, and in 2019, the Apache Corporation awarded it $257,000 to hire additional staff and fund dark skies educational materials, outreach events, and a permanent exhibit on dark sky preservation at the visitor center. “Their work is a win for natural resources, economy, health, and the safety of our workers in that area,” says Joni Carswell, CEO and president of Texan by Nature, an organization founded in 2011 by Laura Bush, MLS ’73, Distinguished Alumna, to unite conservation and business leaders.

The work has long-term effects. “We’ve managed to show good lighting benefits the oil industry, McDonald, and tourism,” says Wren, who in July 2020 began an application to the International Dark-Sky Association to establish a Greater Big Bend International Dark Sky Reserve in far West Texas and northern Mexico. The detailed application they’ll submit in a couple of years will require collaboration among protected areas of Mexico and Texas and private landowners. If approved, the reserve would be larger than the 16 existing Dark Sky Reserves in the world combined. Wren will also work with area organization the Big Bend Conservation Alliance to help formulate a strategy that shows business benefits for conserving water and land.

Conserving dark skies helps in less obvious ways, too. For instance, a 2017 study showed migrating birds are confused by light, demonstrated by birds drawn to New York’s 9/11 tribute. “As a form of pollution, light overuse is a fairly easy problem to fix,” says Cooper Farr, director of conservation at the bird research nonprofit Tracy Aviary and Botanical Gardens in Salt Lake City. “If you shield the lights, the problem is gone. Light conservation is a nice project to work on, because the fix is straightforward and immediate.”

Better lighting brings visibility, safety, and cost-efficiency. “There’s every reason in the world not to use more lighting in the sky,” Wren says. “When 80 percent of the people live where they can‘t see the Milky Way, it’s not just affecting professional astronomers and observatories. Light pollution is having an impact on our culture, our civilization.”