This paper presents the way Galileo’s telescopic observations were woven into a new kind of astronomical discourse that provoked extreme reactions by the Catholic establishment of those days. Galileo, I shall argue, invented his own strategies for dealing with the gap opened up by the telescope between appearances and being – between what seemed to be the case and what actually was out there. In doing so, Galileo added a dimension to the practices of signification common in the political, theological and theatrical arenas of Baroque culture. In each of these areas, the gap between “seem and be” was haunting political actors and courtiers, theologians and playwrights. Obviously, the need to cope with such gap gave birth to new or modified cultural forms, among them new forms of representation and allegory. Following Louis Marin’s work on the discourse of representation around the King’s portrait (Marin 1988), as well as Walter Benjamin’s argument on the centrality of allegorical practices in Baroque theatre (Benjamin 1977), I shall isolate two additional arenas in which Baroque forms of representation and allegory were used: in Galileo’s attempt to cope with the visual evidence about the heavens on the one hand; and in the Inquisition trial of the Medici mathematician-philosopher on the other. My aim is to show that the constitution of a new kind of scientific discourse and the challenge it posed to Catholic hegemony took active part in Baroque rituals of representation and allegory, and that those should not be read as mere literary techniques. Rather, Galileo’s use of representation and allegory involved him in a highly sophisticated system of communication relevant for understanding different dimensions of a baroque scholar’s life. In the last part of the paper I will point out how, during the trial of Galileo, allegorical practices were stretched beyond the limit of signification and transformed into a mode of dissimulation – a recognized practice defined by contemporaries as “dissimulazione onesta”.