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Globe at Night

Main Project Information
Presented By National Optical Astronomy Observatory
Goal Raise awareness about light pollution.
Task Measure the night sky brightness.
Where Global, anywhere on the planet

Seven out of 10 people in the US have never seen our Milky Way Galaxy arch across their night sky from where they live. Have you? If so, you're lucky! If not, it's probably because of light pollution (too much outdoor lighting).

Light pollution not only affects our view of the stars, but it also 1) wastes energy and money (about $2 to $10 billion a year!); 2) causes sleep disorders in people; and 3) disrupts the sleeping and breeding habits of animals like newly hatched sea turtles that try to find their way back into the moonlit ocean but get confused by streetlights and end up on streets instead.

Light pollution may be a global problem, but the solutions are local and it starts with you. In this project, you will go outside and compare how many stars you *can* see in a constellation, to how many stars you *should* be able to see (as depicted on the free app or website you will be directed to once you click "join"). You will mark your location, tell us if it's cloudy, and tell us if you saw most of the stars or not. That's it!

If you want, you can compare your light pollution levels to other reports around the world. Ready? Click "Join" to get started!

How to Join

The basic Globe at Night program is simple: On clear and moonless nights during the 10-day campaign, you go outside at least an hour after sunset but before 10 pm local time. Don't stand under or near a light. Wait about 10 minutes for your eyes to get adjusted to the night sky. Then locate in the night sky the constellation of the month. For January and February, it is Orion, known for its three distinctive stars that make up Orion's Belt. (For the other months of the year, the constellations can be found here:

There is an easy way to take and report observations with the Globe at Night “web” app, using Any computer, any cell phone, any tablet can be used to access this site to take and report Globe at Night observations. If a smart device like a smart cell phone is used, then the date, time and location is automatically put into the report page at as answers to Questions #1 and #2.

In Question #3, you then compare what you see to seven stellar charts depicting varying degrees of light pollution and choose the chart that most closely resembles what you see. (If you are not able to use the charts on the webapp report page, then the charts can be downloaded from the Globe at Night website at The first chart (#1) has only a few stars (similar to light pollution seen from the middle of New York City). The last chart (#7) shows lots and lots of stars (as seen from a National Park). The charts show progressively fainter stars and therefore more of them, providing a good indication of local light pollution levels.

In Question #4, you are asked to choose one of four pictures that show how much cloud cover you had on the night you made your observation.

Optionally, you may also use a Sky Quality Meter, which quantitatively measures the brightness of the night sky. (See for more information.) If you have an “SQM” with which to take measurements, the SQM reading can be submitted to Question #5.

Question #6 simply asks you to click the submit button.

If you do not have access to a cell phone, tablet or computer during your observations, activity guides can be used to help select your chart. (See After observing, you can log on to the Globe at Night Web site, identify the date and time you took the observation, identify your observation location, and amount of cloudiness, and report your observations (e.g., the chart you picked). And that is all. The map of observations worldwide is produced “on-the-fly”. (See

Educators and astronomers are hopeful that young stargazers will ultimately draw the same conclusion about their world: The night sky is an irreplaceable natural resource that's worth protecting. Perhaps one day you and your colleagues can take Globe at Night data to the local government to advocate for regulations on artificial light. Imagine how great the impact could be!

To learn the five easy steps to participate in the Globe at Night program and to obtain important information on light pollution, stellar magnitudes, the mythology of Orion, how to find Orion, how to obtain your latitude and longitude, and how to use a Sky Quality Meter, please see All information needed to participate is on the Globe at Night web site, along with downloadable activity guides. As mentioned, the guides have the steps for participating in the program, the different star charts, reporting form and more and are offered in 26 languages.

Should you be interested in other activities that have children explore what light pollution is, what its effects are on wildlife and how to prepare for participating in the Globe at Night campaign, see the “Dark Skies Rangers” activities at For middle school students who may be interested in how light pollution affects energy, health, wildlife, safety, light trespass and the night sky, you can find problem based learning scenarios called the Quality Lighting Teaching Kit at

In 2015, Globe at Night collected a record number of over 23,000 measurements of night-sky brightness from kids and adults in 104 countries! Help us exceed these numbers this year!

Project Timing The campaigns run 10 days a month when the Moon is not up the first half of the night. See for the campaign dates each month. The times are at least an hour after sunset til 10pm in general. The time can extend til 11pm at higher latitudes where the Sun sets later in the summer, but the Moon (a natural light bulb) should not be in the night sky.
Social Media
Materials List your eyes (adapted to the darkness outside), a red light or flashlight covered by a red balloon (optional), internet access to submit your observation on the report page, address (or latitude and longitude) of observation, the Globe at Night report page or activity guide
Ideal Age Group Elementary school (6 - 10 years), Middle school (11 - 13 years), High school (14 - 17 years), College, Graduate students, Adults, Families
Ideal Frequency Per month
Average Time Less than an hour
Spend the Time outdoors
Type of Activity At night
Training Materials
Class Materials
Media Mentions
and Publications
Tags girl scouts, light pollution, star
Project Updated 06/19/2017