The Globe at Night program is an international citizen-science campaign to raise public awareness of the impact of light pollution by inviting citizen-scientists to measure their night sky brightness and submit their observations to a website from a computer or smart phone. It's easy to get involved - just follow these 5 Simple Steps!

Image courtesy Babak A. Tafreshi

Join us for the December, 2015 campaign!

Citizen scientists from around the world have contributed 21,243 data points so far this year - thank you! Read more in our Globe at Night Newsletter.

Just announced: Campaign dates for 2016!

Can You Find Perseus?

Perseus the slayer of Cetus is most easily seen rising in the East in the winter. The constellation is most easily identifiable as what almost appears to be a wishbone of brightest stars, with the brightest being the center and chest of Perseus. The legs of Perseus are pointing southward and are the forked part of the wishbone and the body and head are the straight line leading up northward. It is easy to find Perseus by either looking southward from Cassiopeia or just to the left of Taurus the Bull.

Practice finding all the Globe at Night Constellations or review the Magnitude Charts.

The current campaign is using the Constellation Perseus. Check out the dates and constellations for our other campaigns during all 12 months of 2015.

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Globe at Night in the News!

Globe at Night webapp

The Final campaign for 2015 is coming soon! Whether you use a smartphone, tablet or computer, you can submit your data in real time with our webapp - now available in 28 languages! Thanks for helping us get 2015 off to a great start!

IYL Cosmic Light

The International Astronomical Union (IAU) is coordinating activities to increase light pollution awareness by running the Cosmic Light theme of IYL2015, partnering in particular with Globe at Night.


Ever wonder what happens to your Globe at Night measurements? Scientists and citizen-scientists are using them in a variety of projects, most of which need multiple data points at the same location over time. This map shows 5,000 locations on Earth where an observation has been made but there hasn’t been a new one in the last five years. Do you or a friend live near one of these points? Help us out by making an observation there! And while you are at it, take a measurement where none have been taken yet! (See the map for 2014 and zoom in to your location to see where data was taken in 2014.)

Did you know?

That citizen scientists in 102 countries participated in Globe at Night in 2014? And they submitted their data in 22 different languages (other than English)! Find out more interesting information about this year's campaigns from our new Globe at Night Interactive Infographic!

Resources for 2015

Globe at Night is truly an international campaign. Our Activity Guides, Postcards, and the data reporting webapp have been translated into many languages. These are all available to download from our Resources page.

Related phone apps

Globe at Night is pleased that two native smartphone apps have become available that integrate well with our campaigns. The Loss of the Night app is available for Android & iPhones. And if you have an iPhone 4S or later, take a look at the IYL version of the Dark Sky Meter app. Both are free downloads!

See how your region is doing in 2015 below. If you don't see very many data points, consider going outside tonight and contributing your own! Compare to other regions or previous years with our regional map generator.