Citizen Science Illuminates Night Light Data: Analyzing the Nachtlichter App

The Nachtlichter project engaged citizen scientists in observing and recording night-time light sources using a dedicated app. Participants surveyed pre-defined routes, classifying and counting lights by type, size, color, and brightness. Researchers corrected for the effects of lights turning off during the night and combined the data with satellite observations to analyze the relationship between ground-level light counts and satellite-measured radiance. The study demonstrates that Nachtlichter data offer a more comprehensive picture than existing public databases, providing valuable insights into urban lighting patterns.