Now in its sixth year, the Great World Wide Star Count gives you a great excuse to enjoy a dark night sky and do something to help protect it from light pollution.
The late, great statesman Tip O'Neill once famously quipped, "All politics is local," and much the same can be said about light pollution. Case in point: A few years ago I moved to a new house that was less than 5 miles from my old one — and in doing so my night sky got at least two magnitudes darker.
So how starry is your starry night sky? You can find out easily, thanks to a sky-awareness campaign called the Great World Wide Star Count. It'll take just 20 minutes or so, and you'll be joined by thousands of equally-curious skygazers around the globe. Do it on your own, with your family, or as part of a larger group.
All you'll need are a clear evening sky sometime between October 5th and 19th, your own two eyes, and a set of simple star charts. First, download the handy five-page activity guide (available in 16 languages) and print the star charts. If you live in the Northern Hemisphere, you'll be looking high up for the constellation Cygnus, and its Northern Cross asterism. If you're south of the equator, the target area surrounds the Teapot in Sagittarius. Each of the seven maps shows stars down to a different magnitude limit, plus one for a cloudy sky.
Then, after stepping out under the early-evening sky and letting your eyes adjust to the darkness, match one of the charts to what you see overhead. Step back inside and report what you've found online. You're done! (Unlike many contests, you can enter more than once! You might be surprised by how much the sky's darkness can vary from night to night.)
GWWSC is a managed by UCAR's Windows to the Universe project. Previous efforts netted more than 22,000 observations. (If you've done this activity before, please do it again! In that way, you can help track long-term trends in light pollution's growth — or, just maybe, its decline.)
Go ahead — participate in the Great World Wide Star Count and become a "citizen scientist"!