The Dark Sky Meter helps citizen scientists measure night sky brightness via an app that runs on Apple iOS devices. The app provides instant information about the night sky quality and also enables citizen scientists to contribute their observations to a global map of sky darkness. (The app can submit citizen scientist measurements to the International Dark Sky Association.)

The Dark Sky Meter app, developed by DDQ, works by taking two pictures. First cover your camera phone using your jacket or a pocket and then press “dark shot” button. Then aim your iPhone to the point in the sky directly above your head and press the “sky” button. The greater the difference between your dark shot and sky shot, the more reliable the data.