International Dark Sky Places

Stars over Big Bend National Park by Tyler Nordgren

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Measuring Night Sky Brightness? There’s an App for That

DSApp 200Astronomers and dark sky-advocates take note—you can now measure the brightness of the night sky using your smartphone. A new app for the iPhone called Dark Sky Meter uses the phone’s camera to accurately measure the brightness of the night sky and deliver the results to a central database that will, in time, create a worldwide map of light pollution.

The International Dark-Sky Association (IDA), a non-profit group that has long been working to help raise awareness of the problems of light pollution, has worked closely with  the app developers and hails the new app as an affordable way to measure the night sky from  anywhere. Bob Parks IDA’s Executive Director says, “The Dark Sky Meter is an easy, inexpensive way to monitor light pollution. I helped to test the app and was impressed by its accuracy.”

The “pro” version of the app sells currently for $3.99 and compares favorably to a handheld device that retails for $130. Results can be viewed on a map that allows users to compare their results with users from around the globe. The “Lite” version of the app is free for download allowing a greater number of users to contribute data. It provides a more simplified version of the results, showing how many times brighter a sky is as compared to a natural night sky.

The ease of making the measurements with the app makes it a great tool for public outreach. Crowd sourcing the measurements at events like star parties and night sky outreach events improves the accuracy of the measurements, increases the public’s awareness of light pollution, and contributes to our understanding of the problem.

App developer Norbert Schmidt and engineer Harro Treur developed the Dark Sky Meter. Schmidt explains, “During the development process we took 5000 measurements by hand and filled in 120 Excel spreadsheets with measurements before releasing the app. Each new measurement collected improves the app’s algorithms making the data more accurate.” Their company DDQ has developed other smartphone science apps, such as one to make fine dust measurements and one for last year’s transit of Venus. More information and download links for Dark Sky Meter is available at www.darkskymeter.com. Currently the most accurate results come from those using the iPhone 4S and 5, but work continues on improving results for more devices.


Android users that are also interested in monitoring the night sky shouldn’t worry as there is a new app called “Loss of the Night“ that they can download for free in English and German at the Google Play Store.



IDA is the only non-profit working to address light pollution around the world. Among it’s efforts, the organization provides information brochures, workshops, a model lighting ordinance, manages night sky conservation program, and awards the distinguished IDA Fixture Seal of Approval to applicants with lighting fixtures that are dark-sky friendly.

Media Inquiries:
Scott Kardel (IDA) This email address is being protected from spambots. You need JavaScript enabled to view it. / 520.293.3198