Born in Eisenach, Grand Duchy of Saxe-Weimar-Eisenach (now Germany), Abbe became director of the observatory at Jena and research director of the CARL ZEISS optical works in Jena. He discovered the Abbe sine condition, which describes a lens that will form an image, without defects of coma and spherical aberration. His mathematical treatment founded the present-day science of optics.