Kerr County Friends of the Night Sky pushes for responsible lighting as Kerrville registers 5-6 on darkness scale

Kerrville sits at a 5 or 6 on the Bortle Scale — a scientific measure of sky darkness that runs from 1 (pitch black, as dark as West Texas) to 9 (the washed-out glow of a major city center). A 7 means, as board member Sheryl Pender put it Monday on Lead Live, “city glow is winning.”

The Kerr County Friends of the Night Sky formed to push that number in the other direction — not by asking people to turn off their lights, but by asking them to use them responsibly.

“I think the pushback is that we’re not telling people to turn off their lights or to get rid of lights,” Pender said. “We’re just saying use responsible lighting.”

The group received its 501(c)(3) nonprofit recognition and appeared Monday during Day 2 of Nonprofit Week alongside board member Marian Clemens. Using NASA satellite data, the organization tracks regional light intensity and advocates for shielded bulbs, warmer amber-toned lighting — blue-white lights are particularly disruptive to biological systems — and the use of 3D-printed shields to redirect existing fixtures downward.

The environmental consequences of light pollution are broader than most residents realize. Light disrupts human melatonin production and sleep cycles, threatens nocturnal animals, and can physically harm vegetation. Clemens described a local tree positioned under a streetlight that withered entirely on the illuminated side while remaining healthy on the dark side.

“We say every tree needs to sleep,” Pender said.

Their Facebook graphic explaining the Bortle Scale recently went viral, drawing 100,000 views.

The group meets the first Thursday of every month at 4 p.m. at the Riverside Nature Center. On Sept. 3, Ben Deose of Dark Sky Texas will present with horizon-to-horizon light data captured by a fish-eye lens camera atop Enchanted Rock. October is Dark Sky Month; Clemens is planning interactive children’s crafts at the library. A community dinner, rescheduled following the July flood, is coming to East End Pizza.

“Absolutely,” Pender said. “This is one of our natural resources. We’re losing it.”

Monthly meetings: first Thursday, 4 p.m., Riverside Nature Center.