Night Skies

Night sky with the Milky Way over a lake
Milky Way over Eagle Lake

Photo by Friends of Acadia, NPS

Acadia’s Night Skies

Imagine laying on Sand Beach and looking up at the multitude of twinkling stars overhead, as the waves crash into the ancient rock which surrounds you. Staring up at the night sky in this protected cove is one of the closest experiences of infinity that human beings may ever have. The rocky shore was first formed in a massive volcano which erupted over the island around 420 million years ago. The shore was then shaped and polished during the most recent ice age, which ended about 17,000 years ago. But that’s nothing compared to looking up into the wide unknown—a universe that scientists now predict was formed 13.7 billion years in the past. Bits of sand—which inevitably invade hair, clothes, and cars—may be an annoyance, but it is far outweighed by contemplating the same exact sky thousands of generations have admired before us.

A Protected Park Resource

Acadia possesses remarkably dark skies for its proximity to Portland, Boston, and New York. The Milky Way dazzles visitors and reminds us just how large our “home” galaxy truly is. When the moon is full, the light it reflects from the sun is so bright it can cast a glow across the ocean. The night skies in national parks, many as breathtaking as here at Acadia, are a protected park resource just like plants and animals.

Night sky with light pollution over a town
Comet NEOWISE and light pollution from Ellsworth, ME

NPS Photo/Josh Cosgrove

Impacts of Light Pollution

Protecting the night sky can pose a challenge in an industrialized world. Light pollution comes in many forms, some not as obvious as others. There are office building fluorescents left on, city lamp posts that spread their beams far beyond what needs illumination, and residences with outdoor fixtures that glare across the street and into the sky. All this can contribute to overall “skyglow,” also known as the brightening of the night sky over inhabited areas. Even at a far distance, this urban light pollution can negatively impact adjacent national parks.

Night Skies and Animals

Besides preventing our view of the awe-inspiring night sky, light pollution also has negative side effects for life on Earth. Some animals need darkness to hunt for prey or hide from predators. Others, such as birds, migrate at night and can be thrown off course by excessive artificial light. Even humans require darkness, particularly to maintain their sleep-wake cycles, known as circadian rhythms.

Heat map showing sky quality across Acadia
This map shows the hot spots of light pollution across Acadia on Mount Desert Island.


Research and Programs

In collaboration with Worcester Polytechnic Institute, Acadia’s Night Sky Initiative was established to measure, promote, and protect the natural night sky in the Park and surrounding areas. This initiative led to in depth technical research to measure sky quality and hot spot areas of light pollution across the park.

Acadia has developed a vast network of educational activities and resources to help educate kids, teachers, and the general public about the importance and urgency of protecting the night skies. During the summer and fall seasons, ranger programs enlighten visitors about how special these dark skies are and inspire them to think about protecting and restoring the darkness where they live as well.


How Acadia Protects Night Skies

Acadia is taking many measures to protect the night sky. In 2011, the park received grants from the National Park Foundation, the Yawkey Foundation, and Musco Lighting to replace fixtures at Blackwoods and Seawall Campgrounds with downward shielded and more energy efficient ones. As lighting fixtures in other areas around the park age and need changing, these are also being replaced in this way. Many fixtures around the park are on timers or motion sensors, which allow them to be on only when needed.

How You Can Help

Here are a few ways you can help, both at the park and back home, to protect and restore night skies:

  • When stargazing on your own, use a red light to protect your night vision (and others).
  • If accessing the park after dark, do not idle in parking areas with headlights on.
  • Check your lighting systems and ask if additional light is necessary. Follow simple steps to fix or replace lights to include downward shielding, timers and motion sensors, and using warm colored lights with only as much intensity or brightness as necessary.

  • For more ideas on how to make a difference in your area, visit the International Dark Skies Association website.

Graphic showing sky brightness over time
National Parks and Night Skies

Learn more about ways the National Park Service protects night skies across the country.

Two people using red lights on a beach at night

Interested in stargazing and astrophotography? Find out about ranger programs and best places to view night skies at Acadia.


More On Night Skies

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    Last updated: October 30, 2020

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