Inspection of surviving mirrors and related objects shows that they were too crude to offer the early Renaissance painter an optical short-cut to a naturalistic image of his subject. The craftsmanship of mirror makers was independent of and inferior to the quality of theories of image formation of the day.

ABSTRACT Our discussion of Niccolò Tornioli's The Astronomers questions some of the traditional identifications of its characters, although we cannot claim to have solved these figures’ identities and several remain a mystery. We do present new iconographic interpretations of particular scientific instruments, diagrams, and natural phenomena in the canvas. These novel readings occasionally remain conjectural in part because Tornioli represents these entities in a way that makes it clear that he did not fully comprehend them. The errors and obscurities in (...) Tornioli’s painting lead us to two conclusions. First, that his erudite patron Virgilio Spada was unlikely to have been involved in the definition of the painting’s iconographies, as he would have objected to Tornioli’s crass mistakes and obscure imagery. Second, that these errors and indistinct details should be taken at face value, insofar as they accentuate the difficulties of astronomical observation. Beyond highlighting these challenges, we argue that the painting also visualizes techniques for countering them. Specifically, the canvas would have focused early modern observers’ attention on the edifying powers of civil conversations and communal observations with scientific instruments as well as images—including diagrams, celestial maps, and paintings. (shrink)