Citizen Science can be a fun way to learn about light pollution while also providing data for use by scientists in data analysis.  

Measuring Light Pollution

The brightness of the sky can be measured using a variety of methods such as sky quality meters, mobile phone apps or just your unaided eye.   Your measurements can be submitted for reporting on a global map of the sky which can be found at  Data submitted to this map can be viewed and downloaded by anyone in the world, including you.

There are several tools/methods to make sky brightness measurements and submit those measurements to the map:

  1. Visual Observations from the "Globe at Night" Project -  Only the ability is to access the internet is needed for this lower tech approach.  During periods near "New Moon" when the brightness of the Moon will not interfere with your view of the stars, count the stars of a particular constellation selected by the Globe at Night Team as noted under the "Observe" tab of their website.  Submit your findings to using the "Report" tab.  Your results will be reported on both and
  2. "Loss of the Night" mobile app - If you have access to a Apple Device or Google Play, you can download an app called "Loss of the Night" for FREE.  This app will guide you through making and submitting measurements to the global map.  (Important note:  We tested this app and found that it only works on IOS.  This app will install on Android devices but is not currently working properly.  We contacted the developer who said they will not be able to fix the issue until more funding is in place.)
  3. "Dark Sky Meter" - This app only works on the IOS 10 or later and will cost you $1.99.  It is commonly used by Amateur Astronomers. The app will take the measurement for you and automatically submit the measurement to the global map.
  4. "Sky Quality Meter" - More sophisticated measuring tools called "Sky Quality Meters" are available from Unihedron or a variety of retailers that sell their product.  The handheld units we use for our handheld checkout program is the "Unihedron SQM-L" model.  Data collected from these observations can be submitted through the Globe at Night Website or any of the apps noted above

Once you have submitted your data using any of the methods above, you can visit the website to view your posting.  Make sure to use the "Filter" tool to select the year and your method of entry (SQM - Sky Quality Meter, LON - Loss of the Night, DSM - Dark Sky Meter or GAN - Globe at Night).  Otherwise, you will not be able to locate your data.  Notice that there is a "Download CSV" button that will allow you to download measurements to a spreadsheet. 

If you have the ability to make the same measurement use multiple methods, use multiple methods to make measurements at the same time and compare the results.  You will note that the direction that you measure can influence the results.  Also, different tools measure a wider field of view than others which can impact results.  If you are able to make SQM observations, compare your SQM measurement to information found on  Use your cursor to select a particular location to reveal an information box with SQM meter readings for that location. These comparative readings were derived from a global atlas of light pollution measurements.

Additional Resources/Projects

  • Explore the website for maps, data and a variety of helpful resources.  
  • Visit to find a variety of projects on "Light Pollution" and wildlife.
  • Visit the "Lights Out" page of the Audubon Society website to learn how you can participate in helping birds migrate safely using safe lighting practices. St. Louis area is launching its own "Lights Out" program in 2020.