Astronomer Diane Turnshek leads the fight for Dark Skies in Pittsburgh and beyond

Diane Turnshek loves to gaze into the infinite beyond of the night sky. But it took an assignment to the remote wilderness of Utah for her to learn how much she was missing.

“When I got to CMU, I asked if they would please send me out West to the Mars Desert Research Station, to crew this small habitat in the upper desert in Utah, which was studying the human factors of space [exploration], like isolation,” she recalls.

Alone with her thoughts, she looked up to the desert sky — and everything changed. She could really see the stars. Not like back in Pittsburgh.

Turnshek learned that it was light pollution that blotted out the stars back home. So she gradually became an activist for so-called Dark Skies, from giving TED Talks to curating art shows and a science fiction anthology.

She also helped Pittsburgh craft its own Dark Sky ordinance. It’s unique for a major city and made national news in August.

The astronomer/activist/Carnegie Mellon University lecturer found her calling. Now, when there’s any sort of anomaly in the sky — such as the meteor that exploded over Pittsburgh on New Year’s Day — The New York Times calls her for a comment. She’s even been working with the United Nations, which has held four major meetings on the subject of Dark Skies in the past several years. Astronauts on the International Space Station are taking photos for her.

Mitigating light pollution doesn’t just help you see the stars. (Though, as an astronomer, Turnshek admits that’s her primary motivation.)

Pittsburgh’s Dark Sky Lighting ordinance calls for the city parks, facilities and streetlights to use LED lights, with lower color temperatures and shielding to minimize the impact on the sky. The National Aviary, Phipps Conservatory and Botanical Gardens and Pittsburgh Zoo & PPG Aquarium have joined the city pledging commitment to Dark Sky Lighting.

The increased energy efficiency (and durability) of LED lights will save the city more than a million dollars a year, says Turnshek, who is from Pittsburgh.

“The city will look better,” says Turnshek. “They’re going to pick warmer tones to the lights, which are actually cooler temperatures, and the city will look more comforting and more inviting — instead of the glare-y, bright blue-white (lights) that they put in prisons.”

Perhaps more importantly, the current streetlights are terrible for the flora and fauna of the city.

You know the bug zapper lights that people put in their back yards? Well, most streetlights attract bugs the same way, which keeps the insects from pollinating at night, and other things they’d normally be doing. If the lights are more toward the amber end of the spectrum, they don’t attract as many bugs.

“It affects plants and animals alike — and even the fish in rivers are affected,” notes Turnshek. “The algae in rivers, there are blooms that go on when you have too much light. So the whole nighttime environment is affected.”

Trees are affected by over-lighting, too.

“If you put a streetlight near one side of a tree, that side will be less healthy,” says Turnshek. “You can see that trees that are shaped so that one side is very healthy — away from the light — and the side towards the light is not healthy, because it blooms too early in the spring. It’s getting its cues from when the sun rises and sets — the daylight gets longer in the summer. The tree is tricked into thinking it’s a different time of year, so it ‘leafs out’ too early, and then a late frost will kill all the leaves.”

Then there’s the impact on humans. There are studies about the effects of constant harsh light on human health and the consensus so far is that over-lighting is likely not good for people, either.

“Studies have to go on for decades and decades and decades before they can feel comfortable making an assertion,” says Turnshek. “But everything that we’ve seen so far shows that there are higher incidences of breast cancer, diabetes, obesity, heart disease, and one just came out linking teen depression to excess light at night.”

Pittsburgh’s leadership on Dark Sky legislation was not a hard sell for the former Peduto administration. Former Mayor Bill Peduto helped produce a documentary about the Allegheny Observatory. Turnshek was part of the former mayor’s transition team.

Dark Sky ordinances are following the International Dark Sky Association’s standards for lighting at night.

“That says, ‘Just light what you need, when you need it, with how much you need,’” adds Turnshek.

The city will replace its 35,000 high-pressure sodium vapor streetlights with LED lights as part of a $16 million project run by the Pittsburgh-based company The Efficiency Network (TEN). But the city’s Dark Sky Lighting ordinance only applies to Pittsburgh properties when the lights need to be replaced, so that part is not going to happen right away.

However, the city also plans to use money from the American Rescue Plan to add up to 15,000 streetlights “to address areas of lighting inequities.”

“If you add 15,000 more streetlights, there’s zero chance you’re going to get a darker city,” contends Turnshek.

So what can we do to stop light pollution?

“Just look at the lights,” says Turnshek. “If your lights are shining upwards — change it, shield it. Refocus it so it goes in the direction you want. If you want to light the steps, just light the steps — don’t shine in your neighbor’s windows. If you want to light the walkway down to the street, then don’t blind the cars coming up the street with your huge, overpowered spotlight.

“People call them security lights. I call them ‘insecurity lights.’ You’re insecure, so you light up the place, like that’s going to prevent crime. But it doesn’t. It just shows the criminals (your house) … There actually have been studies in England, that if your house is dark, and it doesn’t draw attention to itself, there’s less of a chance (of crime) because they don’t want to be out there with a flashlight, the only bright thing around. If you just use motion sensors, that’s security. That’s not lighting it up all night, all the time. Motion sensors, dimmers, use lower wattage and lower temperature bulbs.”