This digital exhibition was collectively elaborated in the course of the ERC ALFA project (CoG 723085, PI Matthieu Husson) with inputs of various kinds from many members. We have spent hours together selecting the manuscripts, shaping the overall architecture and principle of the exhibition, debating each of the few hundred attention points in the manuscripts, discussing the public interface and all the different texts that constitute this exhibition. We hope that it will be a pleasant learning tool for teachers, students, and anyone curious about medieval astronomy and scientific manuscripts.