Key links and information
We count lights, because the night counts

Satellite images of the earth at night show a worldwide increase in nocturnal light emissions and light pollution, including in Germany. Unfortunately, we don’t presently know what types of lights (e.g. streetlights, advertising) are driving this increase, or for that matter, how many of each different type of light there are. Our group of citizen scientists and researchers at GFZ have therefore developed an app to count light sources along street segments – from illuminated windows and advertising signs to street lamps and traffic lights.

Anyone who would like to participate in the counting campaign is invited to do so. Local campaigns will run from the end of August 2021 until the end of October in Bochum, Dresden, Erlangen, Fulda, Potsdam, Würzburg, Preußisch-Oldendorf, and other places (including outside of Germany). During this process, we will count all light sources in selected areas that are visible from the streets, with the help of our „Nachtlichter“ app. This app allows us to record their type, brightness and color. We explain how to use the app in an online tutorial (English, German). Each campaign starts with a kick-off event on site.

After the campaigns, researchers at GFZ Potsdam will evaluate the data, compare it with satellite images of the Earth at night, and publish it. Together we will also contribute to more awareness for sustainable lighting.

Goals of the Night Lights campaigns

We aim to understand how the different sources of light emissions contribute to the light emissions observed by satellite. For this reason, we are sampling lights over large areas, in order to be able to compare what we observe with what satellites see.

We will also investigate and document local differences in the numbers and types of lighting in different places. For example, we will compare city centers to residential neighborhoods, and campaign communities to oneanother.

We create awareness for the transition to sustainable lighting, by inviting citizens in different cities to use our app, participate in our nightlight measurement campaigns, and thus actively engage with artificial lighting and its side effects.

If you think you would like to take part, the first step is to complete our tutorial, and then install the Nachtlichter app on your phone (it’s a progressive web app). If you’d just like to try it out, you can create your own street segment from within the app. However, if you’re interested in covering a larger area to contribute to the scientific project, please contact us. We will work together with you to define a set of transects that match the position of a satellite pixel.

If you have any problems or questions when using the NightLights App, please watch our little youtube video in which we explain how to use the app. If you still have problems, see our answers to frequently asked questions and a number of issues that have happened with the app several times. Since the app is new, it could happen that there are some issues that we haven’t found yet. In case your problem is not listed here, please report it to us with this form (google form). Thank you!

Thanks for your interest in our project!

Christopher Kyba and Nona Schulte-Römer