International Dark Sky Week is April 21–28
By Jaime Herndon
Learning how to protect our dark skies can make a significant impact on human health and the natural world.
April 24, 2025
Science Culture Astronomy Environment Astrophysics Nature Conservation
Most people are familiar with air pollution and water pollution, but did you know there’s also light pollution? According to DarkSky International, light pollution is “the human-made alteration of outdoor light levels from those occurring naturally.” Light pollution can include lights that are too bright, light falling where it’s simply not needed, and confusing or excessive groupings of light sources. Excessive light can negatively impact wildlife and ecosystems, energy conservation, and even the health of humans.
International Dark Sky Week (IDSW) is held April 21–28, celebrating the night. It is a time of raising awareness and of encouraging people to become involved in helping to protect dark skies and reduce light pollution. Things like activities to learn about the night sky in your area, signing a pledge to protect the night, and talking to your local officials to get a proclamation signed are all part of the event.
If you're interested in learning more about the importance of dark skies, I’ve compiled a short list of books that are perfect to explore during IDSW and beyond.
Dark Skies by Anna Levin is a small gem of a book that you’ll want to read slowly and savor. In it, Levin explores what the night sky has represented to people through time, as well as what it’s meant to her. She takes the reader to a variety of settings, illustrating the wonder of darkness within nature, but also detailing why light pollution is a problem, what’s being done to preserve dark skies, how to enjoy dark skies with all of your senses, and how to take action so others can enjoy dark skies as well.
The Observer’s Handbook 2025 (USA edition) edited by James S. Edgar and the 2025 Night Sky Almanac by Nicole Mortillaro, are both published by the Royal Astronomical Society of Canada, and while there is some overlap of contents, you won’t regret using both. They are fantastic resources that provide information about forthcoming astronomical events for each month, information about basic tools like binoculars and telescopes, glossaries, moon phase charts, sky maps, and much more. Both of them are easily portable so you can bring them with you wherever your night sky observation adventures take you!
A Kid’s Guide to the Night Sky: Simple Ways to Explore the Universe by John A. Read is a great book to give to the kids in your life to introduce them to nighttime stargazing—and is just as interesting for adults. This accessible, full-color guide is packed with information, such as how to create a stargazing tool kit, explanations about the life of a star, discussions of the constellations and their relationship with the seasons, and chapters about various astronomical events, the solar system, and the moon.
Night Magic: Adventures Among Glowworms, Moon Gardens, and Other Marvels of the Dark by Leigh Ann Henion reminds readers that when the sun goes down, a whole world comes alive. She explores Ohio, North Carolina, Tennessee, and other places, and participates in a synchronous firefly event, bat outings, a moth festival, and much more. But it is the ordinary nighttime natural occurrences that make the biggest impression, as well as the people she meets along the way who work tirelessly to examine and protect darkness and nature: naturalists, biologists, and primitive-skills experts, to name a few. In exploring the natural world that comes alive at night, Henion also asks about our relationship to nighttime and just how much we know about it.
40 Ways to Know a Star: Using Stars to Understand Astronomy by Jillian Scudder is not about dark skies per se, but I wanted to include this one because if you’re interested in astronomy and dark skies, this is a book you shouldn’t miss. Scudder, an astrophysicist and science blogger, has compiled 40 short essays about different ways to know stars: by their internal structures, as tracers of dark matter, and more. Filled with color illustrations, graphs, and pictures, Scudder's book lays out complex concepts in an accessible, compelling way.
Now that you have a reading list for exploring dark skies, if you’re ready to take direct action to protect them, here are five easy things you can do to help minimize and reduce light pollution in your everyday life.
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