The project Nightlights (German: Nachtlichter) was a citizen science project co-designed by a team of academic and citizen scientists. The citizen scientists were spread throughout Germany, the academic scientists worked at the GFZ. The project aimed to document the sources of outdoor light sources in public spaces (mainly in Germany but with the possibility of contributing worldwide). The goals of the project were to (I) improve the understanding how different sources of light emissions contribute to the light emissions observed by satellites, (II) investigate and document local differences in the numbers and types of lighting in different places, and (III) create awareness for the transition to sustainable lighting.

The co-designed project developed the Nightlights app, organized light counting campaigns in the fall of 2021, and analyzed and communicated the results. This is a combined text and data publication.

The project was funded by the Helmholtz Association’s Initiative and Networking Fund (grant no. CS-003) and received additional funding from the Helmholtz Association (grant no. ERC-RA-0031), as well as from the European Union’s Horizon 2020 research and innovation programme ERA-PLANET (grant no. 689443) via the GEOEssential project. The project was then extended after receiving funding by the Germany Federal Ministry of Education and Research (BMBF) in Science Year 2023.