Filed Under The Environment

Dark Sky over Arches National Park

Home to over 2,000 natural sandstone arches in Utah, Arches National Park applied for recognition from the International Dark-Sky Association and received the association’s “Silver Tier” designation in 2019 thanks to its commitment to preserving the natural sky and educating the public about the benefits of reducing light pollution.

First designated a national monument in 1929, Congress declared Arches a national park on November 12, 1971. Arches National Park is one of the “Mighty 5” national parks of Utah, and in 2019, the International Dark-Sky Associated recognized the park’s work toward reducing light pollution within and outside of the park with its Silver Tier designation. (The Silver Tier is given when light glow is present along the horizon to a degree that wildlife and astronomy are impacted, but the Milky Way Galaxy can still be seen in summer and winter with over six thousand stars visible to the naked eye.)

In 1999, a study of 376 parks discovered that half of all National Parks, 189 in total, were threatened by light pollution from encroaching cities. The National Park Service responded by forming the Night Sky Team to document the negative effects of light pollution with 104 photos taken in a short duration. Every photo was stitched together to form a wider picture, and then the Night Sky Team erased the light generated by stars to focus on how artificial lighting impacted the park. Arches National Park in 2003 had significant light pollution from Moab, Utah, and Grand Junction, Colorado, so the park created outdoor lighting codes with training workshops to reduce light pollution, intending to keep visitors safe while minimizing harm to wildlife.

Arches National Park’s lighting codes implement several strategies for reducing light pollution and preserving a clear night sky as a culture heritage. First, Arches’ lights use motion sensors to provide visitors with light when they need it without leaving any running constantly. Second, Arches’ outdoor light fixtures are shielded with hoods and point toward the ground. Third, Arches National Park uses warm-colored light, as blue-colored light negatively impacts insects while amber lighting minimizes sky brightness while still providing visibility to guests. Fourth, Arches encourages nearby cities and households to plan outdoor lighting efficiently and use high quality lights. This includes striving to minimize nighttime lighting and only using what is strictly necessary for public safety.  Close to 100% of all exterior lights throughout the 119-square-mile park are night-sky friendly in accordance with Arches’ principles.

The value Arches National Park places on its dark skies is not limited to lighting codes and stargazing within the park. Educational outreach programs have been created, like the Night Sky Ranger booklet that teaches children about astronomy and light pollution through stargazing and moon phase observation activities. Preservation can maintain the dark skies, but education about the value of dark skies is what will break through the night blindness created by brightly lit societies.

Images

Milky Way over Arches
Milky Way over Arches The Milky Way Galaxy is visible behind the silhouette of the Delicate Arch, the best recognized landmark in Arches National Park and a well-known spot for stargazing. Because the Milky Way Galaxy is visible, Arches National Park earned the International Dark-Sky Association’s Silver Tier designation. Source:

“Delicate Arch at Night.” Jacob W. Frank. Courtesy of the National Park Service. https://www.nps.gov/media/photo/gallery-item.htm?pg=2242328&id=264B17EA-155D-451F-67A77ACA100D7BD2&gid=275B0E39-155D-451F-6752DA81D6E6018D.

Creator: Jacob W. Frank
Stars over Balanced Rock
Stars over Balanced Rock This National Park Service photo of the night sky at Balanced Rock in Arches National Park is a star trail image. A star trail picture depicts the movement of the stars across the sky based on the Earth’s rotation over a period of exposure. Source:

“Balanced Rock with Star Trails.” Jacob W. Frank. Courtesy of the National Park Service. https://www.nps.gov/media/photo/gallery-item.htm?pg=2242328&id=260796FD-155D-451F-6740FC4D0E174046&gid=275B0E39-155D-451F-6752DA81D6E6018D.

Creator: Jacob W. Frank
The night sky in 2003
The night sky in 2003 The Night Sky Team’s study of Arches National Park in 2003 produced a mosaic image where Moab, Utah, and Grand Junction, Colorado, are the two most impactful artificial light sources on astronomy in Arches. Source: Figure 15 in United States Department of the Interior, National Park Service, Southeast Utah Group, Resource Management Division. Executive Summary: Night Sky Monitoring Program, Southeast Utah Group, Arches and Canyonlands National Parks, Hovenweep and Natural Bridges National Monuments by Charles Schelz and Angie Richman. National Park Service, 2003, 52. Via Internet Archive. https://web.archive.org/web/20201125200655/https://www.nps.gov/cany/learn/nature/upload/NightSky2003.pdf.
The difference dark makes
The difference dark makes The National Park Service at Arches National Park measured the effects of artificial light glow in 2003 (upper half) and 2009 (lower half). The points of glow at the horizon illustrate how the light glow has lessened since 2003 but is still impacting astronomy in Arches. Source: Arches_allskypan_NSNSD_NPS. September 21, 2009. Courtesy of the National Park Service, via NPGallery. https://npgallery.nps.gov/AssetDetail/DB81CF31-1DD8-B71B-0B0CE9B4ED2BA17F.
For junior rangers
For junior rangers Activity pages such as this encourage children to value the night sky as part of their experience with nature. Source: In Campbell, Caitlin Campbell and Arches Junior Ranger Committee. Junior Ranger Adventure Guide. Moab, UT: Canyonlands Natural History Association, n.d. https://www.nps.gov/arch/planyourvisit/upload/Arches-Junior-Ranger-web.pdf. Creator: Caitlin Campbell and Arches Junior Ranger Committee

Location

Arches Entrance Road, Arches, Utah 84532

Metadata

Emma Svenson, Northern Arizona University, “Dark Sky over Arches National Park,” Intermountain Histories, accessed February 24, 2024, https://www.intermountainhistories.org/items/show/541.