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Far From Front Range Light Pollution, Colorado Skies Recognized For Stargazing

The Milky Way over Rocky Mountain National Park.
P. Gaines
The Milky Way over Rocky Mountain National Park.

Last week, Gov. Jared Polis announced that June is “Dark Sky Month” in Colorado. The state is already a global leader in preserving dark night skies.

This year alone, Florissant Fossil Beds National Monument, Mesa Verde National Park and four mountain towns were recognized as dark sky places by the International Dark-Sky Association. With this designation, they join Black Canyon of the Gunnison National Park and Great Sand Dunes National Park.

While these remote locations are good at preserving their starry views, the cities on the Front Range release a significant amount of light pollution. The excess light negatively impacts nearby Rocky Mountain National Park’s night skies, as well as its wildlife.

Above Front Range communities, only a handful of stars are visible in the night sky at any given moment. There’s no hint of the cloud-like Milky Way.

But about an hour west of Colorado Springs,­­ in Florissant Fossil Beds National Monument, the galaxy is clearly visible. The monument’s lead interpreter, Jeff Wolin, said that’s a big draw for visitors.

“Most folks come here during the day and they see petrified tree stumps,” he said. “But a big part of our ecosystem here, of the ecosystem, is the night sky. We say half the park is after dark.”

The monument’s recent recognition as a dark sky park took about three years to complete. Wolin said it was not an easy process.

“Part of that is we have to go through literally every light bulb in the national monument and then identify what kind of light bulbs they are, if they are motion lights, do they come on at night, do they point up, do they point down,” he said. “And then, (we) come up with a plan of how to replace the ones that we need to.”

Location-wise, Wolin said the monument got a bit lucky. They are close to an urban area, but just far enough away. The mountains — including Pikes Peak and the Rampart Range — block a lot of light coming from Colorado Springs and its surroundings.

“It ends up being kind of a unique locality where we have pretty dark skies,” said Wolin.

But other Colorado parks are not so fortunate.

Rocky Mountain National Park’s views brought in over 3 million visitors last year. Public affairs officer Kyle Patterson said there are places in the park that also have dark night skies, but it depends significantly on location.

“When you think of Rocky Mountain National Park, we range from 8,000 feet in elevation to the summit of Longs Peak,” she said. “So, it really depends on if you’re on the top of the mountain or if you’re above tree line, if you’re down in meadows or if you’re in maybe a wilderness campsite.”

A dark sky designation isn't totally off the table.

Patterson said they’ve considered applying in the past, but for a large park with many projects, the process would have stretched the staff thin. They have been updating some light fixtures to be dark sky friendly.

But Kurt Fristrup, a former chief in the Night Skies and Natural Sounds Division of the National Park Service, said Rocky faces another big obstacle.

“You can go up on Trail Ridge Road at night and cast a pretty significant shadow from the light from the Front Range,” he said. There are glowing bubbles of light along the horizon east of the park from Fort Collins, Greeley and Denver.

Light pollution from Northern Colorado as viewed from Soapstone Natural Area.
City of Fort Collins
Light pollution from Northern Colorado as viewed from Soapstone Natural Area.

Patterson agreed that some of the best views in the park have some of the worst light pollution.

“If you're in places like Rainbow Curve, for instance, which is a pull-out overlook on the east side of the park, in those places you’re going to see more of that potentially city glow,” she said.

The Front Range might outshine the stars, but the light pollution also has far worse effects. Fristrup said it’s harmful for wildlife – and not just in the park.

“Having light cycles that are as close as possible to the original light cycles is really important for sleep, for predator-prey interactions,” he said. “There’s no piece of nocturnal ecology that light doesn’t touch.”

Unnatural light can force animals in or out of areas they wouldn’t normally visit. It’s also been shown to disorient migrating birds. Similar to a lamp attracting a moth, a bird can be drawn to a lit-up building. And Fristrup said that harmful light is just wasted energy.

“It gets in the way of astronomy, it gets in the way of visitor enjoyment of night skies and the stars,” he said. “In fact, our communities around the Front Range would have a spectacular night sky if we were just a little smarter about our outdoor lighting.”

But there is hope. There are plenty of options for bulbs that don’t contribute to light pollution. Even shielding or directing a light towards the ground can help. Cities like Fort Collins now require that every new building uses dark sky friendly lighting.

And switching to a better light has immediate results, whether you are stargazing in your backyard or at a national park this summer.

I am the 2021 American Association for the Advancement of Science Mass Media Fellow at KUNC. My goal is to tell the true stories of science — and make them understandable and fascinating for all.
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