West Texas is famed worldwide for its vast crude oil reserves. But for over 75 years, a small patch of the Permian Basin has also been valued for its pitch-black night sky.

Those two prized natural resources have clashed in recent years as oil drilling has brightened the sky near McDonald Observatory. A collaboration between the petroleum industry and the observatory — home of North America's largest telescope — appears to have made progress in slowing the creeping light pollution.

But there are no guarantees about the night sky's future as Permian Basin production hits record levels and drilling inches closer to one of the darkest spots on the continent.

"Fortunately, we're far enough away — at least for now — from most of the oil and gas activity," said Bill Wren, special assistant to the observatory's superintendent. "And we're surrounded by mountains, so we don't actually see it line-of-sight. We just see a glow on the horizon. ... The sky overhead is still incredibly dark."

To understand what was happening to their night sky, staff at the University of Texas-owned observatory started measuring the amount of artificial light in August 2015. The sky then was 14 percent brighter on average than if the region had no artificial light. By November 2018, it was 43 percent brighter.

While the increase is worrisome, it's not a disaster. Almost all of that light is low in the sky. "Astronomers typically are not aiming their big research telescopes down in the dirt to look at objects close to the horizon," Wren said.

For now, there's been no measurable increase in brightness in the night sky high overhead, he said. But the overall increase in light has changed the way the observatory operates from its perch above the West Texas plains.

"For most of the history of the observatory, the brightest thing in our sky — apart from the sun and the moon — was El Paso and Juarez," Wren said, pointing out that those cities are 160 miles away. "Now you can see that El Paso is largely swamped by the sky glow coming from the Permian."

A look at the glow from artificial light sources near McDonald Observatory in West Texas. (Bill Wren)

'Gates of Heaven'

The observatory outside Fort Davis exists thanks to East Texas banker William Johnson McDonald. With no wife or children, he left his estate — worth nearly $1 million in 1926 — to the university. His demand was that UT create an astronomical observatory, one with a telescope large enough to peer into the "gates of Heaven."

University officials found an ideal site in the Davis Mountains, thousands of feet above sparsely populated West Texas.

The telescope was the world's second-largest when it was dedicated in 1939 and trailed only the Mount Wilson Observatory near Pasadena, Calif. When McDonald Observatory was built, Wren said, light pollution from the booming Los Angeles area was already starting to affect Mount Wilson's research.

In the decades since, McDonald Observatory has built even larger telescopes and still has one of the world's largest. The 22-year-old Hobby-Eberly Telescope is getting a $30 million upgrade to help it keep pace with the observatory's rich research history.

Scientists in the Davis Mountains have figured out methods for calculating the size of stars by their brightness and temperature, divined the shape of the Milky Way galaxy, and found the most distant supernova.

Astrophysicists at the observatory discovered the atmosphere on Saturn's moon Titan. They bounced a laser off a reflector left on the moon by astronaut Neil Armstrong and measured the distance to within a few inches.

Wren describes his workplace as the "jewel of the UT system."

Books from the original W.J. McDonald Collection are illuminated by a flashlight at McDonald Observatory. (Ryan Michalesko / Staff Photographer)

Lighting the way

Telescopes and oil drilling were never designed to coexist.

Signs on the final stretch of road leading to McDonald Observatory warn against the use of headlights. And when staff members wander about in the dark, they use small lights that provide just enough illumination to guide their paths.

A few dozen miles away, 24-hour drilling operations are underway with light towers, each powerful enough to illuminate a half-dozen or more acres.

While those two worlds are now in conflict, there isn't a fight over who wins.

After reaching out to the industry several years ago, Wren said he's received largely positive responses. Early offers of help came from Stacy Locke, president and CEO of San Antonio-based Pioneer Energy Services.

Locke said he knew little about the observatory at the time but valued the night sky. At his wife's family ranch near the West Texas town of Marathon, Locke said: "You see stars on every horizon you look at. The stars go right to the ground."

But elsewhere, development had snuffed out sections of night sky. Locke and Wren both lament that generations of children are growing up without ever seeing a clear view of the Milky Way.

When Wren asked Locke if it was possible to make a drilling rig dark-skies compliant, he said: "We don't really know, but we're willing to try."

Pioneer Energy Services gave observatory staff access to the company's rigs. During his first visit, Wren said he noticed a rag stuffed in the mesh covering of one light. A worker told him the workaround was needed to reduce the distracting glare.

"That was the smoking gun," Wren said. "I knew we could do better than a rag."

Before and after pictures of Pioneer Energy Services equipment outfitted with dark-skies compliant lighting. (Pioneer Energy Services, McDonald Observatory)

Industry collaboration

Working with Pioneer Energy Services and the Apache Corp., Wren has been able to assemble guidelines for lighting drilling rigs that are beneficial to both sides.

The overall ideas were simple. Shield the lights and point them downward to reduce glare. Also, switch from bluish "daylight" LED lights to softer yellow ones.

It took some technical know-how to implement those broad ideas. But the final results have been endorsed by the Permian Basin Petroleum Association, Texas Oil and Gas Association and the American Petroleum Institute. The Texas Railroad Commission, which regulates the industry, has previously sent dark-skies information to drillers near the observatory, and a spokeswoman said there are plans to do so again.

"Without mitigation, the gleam of light from oil and gas operations could compromise the research for which the McDonald Observatory is famous," the railroad commission wrote in a 2016 letter to operators.

Apache Corp., a partner with McDonald Observatory in its Dark Skies Initiative, has implemented those best practices on all sites near the observatory. Buy-in from Apache was critical since its 350,000-plus-acre Alpine High discovery is the closest field to the observatory. In late December, Apache had seven active drilling rigs there.

Marcus Bruton, manager of health, safety and environment for Apache, said he was skeptical at first of this dark-skies effort. The conventional wisdom in the oil patch, he said, was that more light was better.

"I had to see it for myself," Bruton said. "I had to see the light properly aimed and illuminating the location the way that they do before I really believed it."

Now, Bruton said, he and the rest of the company are convinced. Dark-skies lighting is now part of new employee and contractor orientations. The company's in-house staff checks more than 1,000 lights a week to ensure that they're compliant.

Bruton said that when 100 percent compliance was announced at a staff meeting for the first time, there was a round of applause.

"When you get 'em all, that's when you know that it's more than just an initiative, it's more than just something we talk about," he said. "It's in your culture."

McDonald Observatory public affairs specialist William Wren discusses one of the observatory's telescopes. (Ryan Michalesko / Staff Photographer)

Uncertain sky

Even with all that progress, Wren still has to work hard to protect the observatory. The telescopes are competing for space with one of Texas' most storied and influential industries, with companies accustomed to a light regulatory touch.

From day one, cooperation rather than conflict has been Wren's goal. When he speaks to groups, he emphasizes that new dark-skies compliant lighting also saves operators money and provides a safer work environment.

Wren isn't even seeking to have the lighting ordinances enforced in the seven adjacent counties. "They are vehicles for education and awareness, to get the topic on the table," he said.

Taylor Keys, program manager at Texan By Nature, a pro-business environmental group founded by former first lady Laura Bush, has been working with Apache on a cost-benefit case study. She said the research should generate concrete numbers on the savings from the new lighting, both in electricity costs and accident avoidance.

"The goal is to have companies take this to heart," she said.

Although big, influential players are on board, the Permian Basin is filled with countless drillers and contractors. And the efficiency of lighting rigs isn't necessarily a foremost concern when scrambling for position in a booming oilfield.

Wren jokes that it's "one down, 1,000 to go."

"We know the activity is growing closer," he said. "It'll be all the way down to Big Bend before all is said and done. ... They've gotten so good at directional drilling that they can pretty much get to anything."