The Feuerkugel app: A co-designed mobile application for documenting fireballs

Fireballs, also known as bolides, not only generate excitement among the general public with its spectacular display of light in the atmosphere, but they also hold valuable information about our solar system. Therefore, the record of their occurrences and the reconstruction of their trajectories are much desired, especially when the latter leads to the collection of fireball remnants reaching the Earth’s surface, which packs vast amount of unique information on the universe. However, many fireball events go unrecorded due to the limited coverage and frame rate of existing sky surveillance camera networks. To bridge this gap, a collaborative effort involving astronomy enthusiasts, astrophysicists, and data scientists has given rise to the Nachlicht-BüHNE project, in which a web-app called “Feuerkugel” enables all interested persons to intuitively submit detailed descriptions of fireball events. Each description includes the duration and color of the event, and the direction of the fireball’s trajectory, which can be effortlessly observed by our eyes. These parameters are subsequently used to reconstruct the trajectory of a fireball. As the web-app received increasing attention from the general public and collected a large number of fireball reports, we are examining the quality and quantity of the submitted fireball reports of the last 3 years. Fireball events recorded by the web-app are compared with records of dedicated sky surveillance camera networks in Germany and France. Based on this analysis, further improvements of the current tool that helps human observers to report fireball events and the data processing methods can be implemented. Additionally, we are analyzing the error of the reconstructed flight trajectories. Therefore, the web-app is extended to allow users the selection and mapping of high-flying commercial aircrafts, with known flight tracks, instead of fireballs. The retrieved trajectories of aircrafts are compared with their known flight tracks to estimate the positional error that we transfer to fireball trajectories afterwards. In this contribution, we present the added value arising from the participation of different stakeholder groups, the structure of the web-app resulting from this participative approach and selected results of the quality and quantity analysis