The essay describes the life and work of the distinguished astronomer Augustin von Hallerstein. It examines the scientific training he received in his native Carniola, his departure from Carniola in his midthirties, and his subsequent correspondence to his homeland up until the time of his death. The author then turns to Hallerstein’s scientific works published by the St. Petersburg Academy of Sciences, his relations with his fellow Petersburg aca demician Delisle, and their joint efforts in astronomy. Hallerstein also collaborat ed on electrical experiments performed in Beijing, and his communications to Europe prove that the scientific work of Jesuits in Beijing did not collapse in the 18'^ century until the suppression of the Jesuit order itself.