If anyone needs proof that protecting Glacier National Park’s dark sky is a worthy cause, all they have to do is look at John Ashley’s photos.

For nearly three decades, the Kila resident has documented the park after sunset and the results are now presented in his new book, “Glacier National Park After Dark.”

“This is 28 years of my life,” Ashley said, gesturing to some of his night photos. “It’s the result of a lot of sleep deprivation … Glacier is amazing during the day but it’s even more amazing at night.”

Ashley hopes the book brings attention to a topic that is near and dear to him: Glacier’s night sky and light pollution. Ashley, who has worked as a photographer, biologist and seasonal researcher in Glacier, said that in the years since he began documenting the night sky he has noticed subtle changes. For example, years ago, when shooting on the east side of the park it was possible to see the stars from horizon to horizon. But these days, if Ashley points his camera west, light pollution from the Flathead Valley can be seen sneaking over the horizon. The same goes for when he is shooting north at Lake McDonald, where the lights from Alberta can obscure the distant stars.

Although distant light pollution is encroaching on Ashley’s viewfinder, he said that the sky around Glacier is still spectacular, so much so that you can even see the Andromeda Galaxy, which is located about 2.5 million light years from Earth.

But not everyone is so lucky. Nearly two-thirds of residents in the continental United States cannot see the Milky Way from where they live and that number is increasing because of urban light pollution. In some cases, the lights from a city or urban area more than 200 miles away can disrupt the views in a rural area.

In hopes of keeping Glacier’s sky dark, the National Park Service is working with its Canadian counterpart to designate Glacier and Waterton parks as the first international transboundary dark sky preserve. Since 2006, the International Dark-Sky Association has certified more than two-dozen parks around the world as dark sky preserves. To obtain that certification, a park must reduce the amount of light pollution it produces by installing dark sky-friendly lighting, which only illuminates a space below, not above a horizon line.

Mark Biel, national resource program manager for Glacier, has been heading up the initiative and just completed a lighting assessment of the park last week. He said the assessment took three years and officials were surprised at just how many light sources are in the park. Now, the park will look at ways it can reduce its light pollution and install new dark sky-friendly lights in the future. That lighting installation plan will be part of Glacier and Waterton national parks’ joint dark sky application, which Biel said will be completed later this year.

“A dark night sky is an overlooked and valuable resource here because a large percentage of Americans have never even seen the Milky Way, but they can see it from their national parks,” he said. “You can see what the world looked like before the industrial revolution.”

Ashley said efforts like the dark sky preserve designation for Glacier are great, but added that it will take a regional effort to protect the darkness. He said communities around the park will also have to turn off or dim their lights as well and he hopes that his new book can illustrate what is at stake. He also said that there are economic and health benefits to preserving a dark sky. Environmentally friendly lighting is known to be cheaper in the long run and there are documented health benefits to sleeping in true darkness.

“The good thing is that decreasing our light pollution is as easy as turning off a light,” he said.

John Ashley’s new book “Glacier National Park After Dark” is on sale for $29.95. You can purchase it at area bookstores or inside the park. You can also order it online at www.johnashleyfineart.com.