Little is known about Corbinianus Thomas, a Benedictine monk at Salzburg, but his Firmamentum is one of the unsung treasures of celestial cartography. It contained 54 small charts of individual constellations. Thomas used an interesting nomenclature system: Bayer Greek letter, Roman numeral for magnitude, and Arabic numeral for reference to a star catalog. This system originated on the large globes of Coronelli, as did many of Thomas's figures.
Splendid chart of the constellation depicting Perseus, the Rescuer of Andromeda, slaying Medusa.