Comet NEOWISE appears in the northwestern sky over Little Bitterroot Lake in Marion on July 15, 2020. Hunter D’Antuono | Flathead Beacon
Summer Preview

A Guide to Gazing at Glacier’s Celestial Wonders

Waterton-Glacier is designated as an International Dark Sky Park, and rangers will resume nighttime astronomy programs this summer

By Micah Drew

Of the many dazzling displays of stellar luminance that grace the night skies each year (remember 2020’s NEOWISE comet?), the Perseids meteor shower each summer is one of the most exciting.  

Under the best viewing conditions — a moonless night, clear skies and limited light pollution — Perseid-watchers can expect to see as many as 100 meteors streaking overhead each hour. 

The meteor shower is visible from mid-July until the end of August, but it peaks as the Earth moves through the densest part of the Comet Swift-Tuttle debris field. In 2021, that peak occurred on Aug. 12, the same day Waterton Lakes National Park and Glacier National Park (GNP) achieved full certification as an International Dark Sky Park, joining more than 130 certified International Dark Sky Places around the world, and cementing itself as a near-perfect spot for viewing nighttime wonders such as the Perseids.

Waterton-Glacier International Dark Sky Park (IDSA) is the first transboundary IDSA in the world, adding to the shared parks’ joint designations that include International Peace Park, Biosphere Reserve and World Heritage Site. 

“Dark night skies are an important wilderness characteristic at Glacier National Park. Clearly seeing the expanse of the universe increases a person’s sense of solitude well beyond that of the terrestrial landscape,” said GNP Acting Superintendent Pete Webster when the designation was announced. “A Dark Skies designation aids International Peace Park visitors in finding their own wilderness solitude.”

The official designation from the International Dark Sky Association follows more than a decade of work between the two parks and partners like the Glacier National Park Conservancy, which has financially supported Glacier’s night sky education program, and the Big Sky Astronomy Club, which helped with the application process. A preliminary IDSP designation was granted in 2017.

 One portion of the application included collecting data from across the park including measurements of nighttime luminance using a sky quality meter (SQM) throughout the parks.

According to Mark Biel, Glacier’s natural resource program manager who spearheaded the process, most places within the park have an SQM rating of 21.5 to 21.8, just a few points below a perfect 22 for a moonless night with zero artificial light. For comparison, the SQM rating of an overly lit urban area would be in the mid-teens.

“This was not a simple one-page application,” Biel said of the decade-long effort (it was over 200 pages). “There was a lot of work that needed to be done.”

Part of the application required Wheeler to inventory every exterior light fixture in each park — Glacier alone has more than 2,000 — and draft a comprehensive plan to transition each light fixture to fit dark sky lighting requirements. 

 “Our club members put in the better part of two summers helping inventory all the existing lights in the park when we were in the application process,” Big Sky Astronomy Club President Mark Paulson said. “I’m just thrilled that our efforts were successful.”

Dark sky compliant lighting follows several principles including using warmer color lights, targeting lights using shielding and careful aiming, and utilizing timers or motion detectors whenever possible. When Waterton-Glacier received the initial IDSP designation in 2017, only 29% of the parks’ lighting met the necessary standards. Now, more than 67% of park lighting is night-sky friendly.

“It all boils down to the park’s mission to protect the natural environment,” Paulson said. “Part of that natural environment is the night skies, even though people don’t normally think about that when they visit.”

A 2016 study published in Science Advances found that nearly 80% of North America’s population cannot see the Milky Way at night due to pollution from artificial lights. To preserve and protect the remaining dark sites around the world, the International Dark Sky Association was founded in 2001 to help communities, parks and other protected areas to implement dark-sky protection practices. 

In order to keep the IDSP designation, Glacier and Waterton are required to maintain a robust educational program. During 2020 and 2021, Glacier paused hosting their star viewing parties, but plan to resume them this year according to Public Affairs Assistant Brandy Burke. 

Interpretive rangers will host astronomy programs at both Apgar and St. Mary visitor centers this summer beginning in mid-July and running through late August or early-September, weather permitting. 

Park staff have not yet decided whether they will resume the popular Logan Pass star parties, as over-night construction along Going-to-the-Sun Road will present issues getting stargazers to and from Logan Pass. Schedules for all ranger-led astronomy programs can be viewed at www.nps.gov/glac/planyourvisit/astronomy-programs.htm 

If you can’t make it into Glacier Park, or another nearby location to stargaze, you can still catch a glimpse of the star-studded skyscape thanks to the night-sky webcam installed at Glacier’s Dusty Star Observatory. For digital visitors who can’t stay awake that late, each morning Glacier Park posts a time-lapse video of the previous night’s sky camera, which records the moon, the stars, and the Milky Way rising overhead, as well as clouds streaking past, lightning flashing inside thunder clouds, and during meteor showers, numerous streaking space rocks.


June 19-27: Planets Aligned

In the predawn darkness, Mercury, Venus, Mars, Jupiter and Saturn will line up above the southeastern horizon. All five planets stand out for being visible to the naked eye, but bring a telescope for an even more amazing view. 

July 13: Supermoon

July 14-Aug. 24:
Perseids Meteor Shower

The Perseids will peak on Aug. 13, with meteors visible in vast numbers for around two weeks before and after, although the full moon will be Aug. 12, which may dampen the show.

The best viewing time is close to 4 a.m., although they can be spotted starting around 10 p.m. when the constellation Perseus, begins rising in the northeast. 

Aug. 12: Supermoon 

Aug. 14: Saturn at Opposition

The ringed planet will be at its closest point to Earth and will appear brighter than any other time this year. With a medium or large telescope, rings and a few bright moons may be visible. 

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