The frontispiece of Riccioli’s treatise depicts not two, but three major systems of the world. The Ptolemaic system rests discarded (lower right corner) because of the phases of Venus and Mercury (upper left corner). All-seeing Argus looks on, holding a telescope. Urania weighs in a balance the two chief world systems which remain: The Copernican appears as the standard against which alternatives must be measured. Riccioli’s semi-Tychonic system weighs in as the most warranted. A comet and several telescopic discoveries (upper right corner) include the banded appearance of Jupiter and the ring of Saturn.