HUYGENS, Christiaan (1629-1695). Systema Saturnium, sive de causis mirandorum Saturni phaenomenon, et comite ejus planeta novo. The Hague: Adrian Vlacq, 1659.
4o (194 x 152 mm). One folding engraved plate, 11 engravings in text, 8 woodcut text diagrams, woodcut initials. Later vellum; quarter morocco folding case.
FIRST EDITION OF THE FIRST FULL ANNOUNCEMENT OF HUYGENS' DISCOVERY OF THE RING AND SATELLITE OF SATURN. "Multiple images are used throughout to reveal new findings, narrate movements of the planets and its satellites, and catalog previous research... In another superb display of data, Huygens used multiple images to record and compare previous views of Saturn along with the names of the astronomers who published these views. Depicted [in the illustrated plate] are 13 interpretations of Saturn--all of them wrong--based on observations made before Huygens solved the puzzle of the rings. A foldout from Systema Saturnium, this multiple visually reviews the scientific literature from 1610 to 1645. All these squashed images appear to be stuck flat on the projection plane, as the rings were read two-dimensionally rather than as three dimensional objects encircling the planet" (Tufte, Visual Explanations, pp.106-107).
The mystery of Saturn's "arms" had puzzled astronomers in the decades following Galileo's observation in 1610 of the planet's oval shape. Starting in the 1650s, Huygens and his brother Constantijn acquired great skill in the grinding and polishing of spherical lenses, and the telescopes that they built were the best of their time. In 1655, using their first greatly improved telescope, Huygens spotted a satellite of Saturn, later named Titan. Although still unable to physically make out the cause of Saturn's odd and variable shape, Huygens theorized that it was due to a single flat ring, whose inclination to the line of sight varies. "He arrived at this solution partly through the use of better observational equipment, but also by an acute argument based on the use of the Cartesian vortex (the whirl of 'celestial matter' around a heavenly body supporting its satellites)" (DSB). In 1656 Huygens presented his theory in a one-sentence anagram included in Pierre Borel's De vero telescopii inventore, thus securing priority of the discovery. The Systema Saturnium contains as well "many other observations on the planets and their satellites, all contributing to an emphatic defense of the Copernican system", and an observation and illustration of the Orion nebula. Dibner Heralds of Science 9; Norman 1136.