Protect the night sky — join the International Dark-Sky Association for activities during International Dark-Sky Week.

International Dark Sky Week 2023
International Dark Sky Week has been running since 2003 when, after much hard work and planning, then-high-school student Jennifer Barlow from Midlothian, Virginia, kickstarted the event. National Dark Sky Week, as it was known at the time, has since ballooned into an international event, now celebrated around the world. It's now coordinated by the International Dark-Sky Association, which is heavily invested in preserving our night skies and in raising awareness on the harmful effects of light pollution.
International Dark-Sky Association

International Dark Sky Week kicks off on April 15th and concludes on April 22nd (which also happens to be Earth Day and the peak of the Lyrid meteor shower). This annual celebration of the night sky is normally scheduled around the new Moon, which this year is on the night of April 19–20.

The purpose is simple: to highlight the negative — and sometimes downright harmful — consequences of light pollution. But it’s also a platform for fostering inspiration, to encourage seeking solutions, and ultimately, to celebrate the night.

Light pollution is “the inappropriate or excessive use of artificial light,” according to the International Dark Sky Association (IDA), the leading champion in the fight to preserve dark skies. This pollution comes in many forms: the interior and exterior lighting of buildings, advertising billboards, sports stadiums, factories, streetlights, commercial properties . . . the list goes on.

Light pollution cuts out most stars
Light pollution affects not only city-dwellers, but also spills into the neighboring countryside in the form of highway lighting, for example. City lights erase all but the very brightest objects in the night sky, rendering many constellations unrecognizable. But light pollution doesn't only affect astronomers — it has far-ranging harmful effects on all creatures.
Fabrice Villard

Until recently, humanity — and nature — lived according to the ebb and flow of sunrises and sunsets, with nighttime landscapes illuminated solely by the gentle light of the Moon and the stars. We slept when it was dark and rose with the Sun. With the advent of electricity and 24-hour lighting, we’ve lost touch with our circadian rhythms.

A groundbreaking 2016 study found that a whopping 80% of the world’s population lives with the consequences of skyglow, the brightening of the night sky due to street and house lights. If you live in the United States or Europe, you're likely worse off: Skyglow and other detrimental effects of light pollution hide the Milky Way from an eye-watering 99% of the population. Visit NASA's Blue Marble Navigator to see at a glance how bad light pollution is in your area.

Light pollution doesn’t only blot out the wonders of the universe. It also severely disrupts wildlife and the ecosystem — insects fail to propagate, birds become confused in their migrations, and it even affects the growth patterns of trees. Disrupted circadian rhythms affect humans, too, increasing the incidence of certain cancers.

International Dark Sky Week 2022
Light pollution harms mammals, birds, amphibians, insects, and reptiles. It can decrease reproduction, disrupt migration, increase predation, and more.
International Dark Sky Association

Celebrate Dark Skies

This upcoming week is a wonderful opportunity to learn more about light pollution, what the IDA does to raise awareness, and what you can do to help them in their endeavor.

International Dark Sky Week 2022
The quality of your night sky depends a lot on the lighting in your environment. A lot of outdoor lighting at night is inefficient, overly bright, poorly targeted, improperly shielded, and sometimes completely unnecessary. This light and the electricity used to create it are being wasted because it spills into the sky rather than being focused on the objects and areas that people need illuminated.
International Dark Sky Association

Spread the word! The IDA has compiled a helpful and informative outreach package that you can dip into during this week to share with your friends and family. But there are also educational and fun activities you can engage in:

  • Contribute to the National Science Foundation’s NOIRLab campaign, Globe at Night, by measuring night sky brightness observations. Researchers use this information to inform policy-makers about where and why light pollution is occurring. All you need is a smartphone, tablet, or computer. Find their campaign dates and follow their instructions: Go outside more than an hour after sunset (if skies are clear, of course), then wait while your eyes adjust to the darkness, about 10 to 20 minutes. You can then upload your observations of a constellation of your choice.
  • Participate in a Scavenger Hunt! Grab your family and friends and see how many items you can find on the IDA card during the week — use the markup tool on your phone (a pen or marker on a paper copy will also do). Find them all? The IDA will send you an assortment of stickers after you fill out their form.
  • Spread the word on your own social media accounts. If you do, be sure to use the official event hashtags: #DiscovertheNight, #IDSW2023, #DarkSkyWeek. Do you have your own website? That would be a great place to blog about International Dark Sky Week, the IDA, and ongoing efforts to mitigate light pollution.
  • Be bold, go bigger: Contact your local radio and television stations and inform them of this week — inspire them to discuss light pollution and its harmful effects in one of their regular scheduled programs.

Keep an eye on the IDA's Facebook and YouTube pages — many events will stream live during the week.

Raising Local Awareness

International Dark Sky Week is a good place to kick-start your light-pollution-combating efforts, but there are things you can do after April 22nd, too. Start close to home by taking a proactive stance: Inventory your home lighting to ensure you have the right types of bulb and avoid contributing to light trespass, unnecessary light that spills from your property into your neighborhood. Check out the IDA’s recommendations for Responsible Outdoor Lighting.

You can also raise awareness in your local neighborhood. You'll find advice on how to approach a neighbor to discuss their lighting. Just remember: Always be polite. Visit the IDA’s Public Outreach website to find material such as brochures, infographics, and videos that you can share in your community and with your friends and family.

Different types of lighting and their effects on the night sky
Choice of lighting can make a big difference to the darkness of your local night skies. You might want to approach your elected official to let them know that streetlights in your area might be bothersome. Even the lighting you and your neighbors choose for your home can have a big impact on not only your access to dark skies but also to the wildlife that inhabits your neighborhood. But there are ways to tackle those issues.
International Dark-Sky Association

If streetlights are the nuisance in your area, find out which local governmental agency (usually a utility department) is responsible and contact them. Let them know how the light is bothering you and your neighbors — and whatever wildlife shares your backyard. Drop them a helpful hint by sending them the IDA's website.  

You can also take on a more active role and join the IDA Advocate Network. After following a few preliminary steps you’ll be invited to join the IDA’s global communication platform, which will give you access to exclusive resources as well as opportunities to learn more about dark sky conservation.

As inspiring as International Dark Sky Week events may be, your efforts needn’t come to an end on April 22nd. Combating light pollution is an ongoing, global endeavor — and it might even become a lifetime passion for you.

But first, switch off the lights, step outdoors, and discover the night.


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