Draloric
First Post
I like anno post casum stellae well enough, although anno post casum cometae contains most of the meaning I think you're striving for. Casus, means "fall," of course, but it also carries the extended senses of "calamity," "plight," "disaster." Cometa means "comet" or "falling heavenly body," but cometa (at least in Medieval Latin--probably earlier as well) also carries the sense of being something portentious. You might also consider a structure like the Roman AUC (ab urbe condita, "from the city having been established/built") dating system. E.g., a cometa casa, or a stella casa "from the star having fallen."
