In this article, an unknown printed sheet produced by the printing press of the Jesuit-Guarani missions is analyzed. The sheet, whose first words are “Eclipsis Lunae observata in doctrinis…”, was printed in 1708 or later and consists of a single page written in Latin. It contains an astronomical observation made by the Jesuit Buenaventura Suárez and sent to the Royal Society of London. The only known surviving copy is located in the University of Virginia Library. In the introduction, the historical context of the missionary print culture and the state of the art of the
Jesuit-Guarani printing press is provided. In the first part, the production, circulation, and reception of “Eclipsis Lunae obse rvata in doctrinis…” is described. In the second part, the printed sheet is placed within the broader context of the texts produced by the Jesuit-Guaraní printing press.
The (necessarily conjectural) hypothesis is that “Eclipsis Lunae observata in doctrinis…” should be understood both as an astronomical-scientific record and as a propaganda artifact, aimed at showcasing the development of missionary print culture within the world republic of letters.
