Accessibility links

Breaking News

Website of the Week — Star Count

Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

This week it's a website where you can help astronomers track a major problem clouding their observations while learning about the stars and how human activity is affecting one of the oldest of all sciences.

WARD: "The Great World Wide Star Count is a student and family activity, where we're asking people all the way around the world to go outside and look at their night sky and measure the amount of light pollution."

Dennis Ward is an astronomer at the University Corporation for Atmospheric Research in Colorado, home of the Great World Wide Star Count at

Star Count is real science, but you don't have to be an experienced skywatcher to take part. Just follow the instructions on the website; they're available in at least six languages. They explain how to identify the constellations Sagittarius in the southern hemisphere and Cygnus in the north.

WARD: "And they have a series of charts that show what that constellation might look like under the different amounts of light pollution, the different limiting magnitude of the sky. And all we're asking people to do is just compare their view of that constellation with one of seven charts that are in this activity guide."

No matter where in the world you are, Star Count wants your observations, but Ward is especially interested in reports from the Southern Hemisphere. You can submit more than once, at different times or from different places. Results will be available at the end of the two-week observation period.

WARD: "After the campaign is over, in mid-October, all the data that everyone around the world has been collecting, we'll make that available to everyone so they can do their own analysis. We'll have it available in spreadsheets and text files, and even some mapping formats. We'll have step-by-step guides on how to do that."

Dennis Ward says the plan is to make the star count an annual event, so changes in light pollution can be tracked over time.

The Great World Wide Star Count ends on October 15, so hurry over to, or get the link from our site,