In this work, Huygens resolved the enigma of Saturn’s changing telescopic appearance by proposing that a ring surrounds Saturn at an angle, varying in visibility from the Earth. When Galileo first observed Saturn, it appeared as if in three parts, with “ears.” Shortly thereafter, the “ears” disappeared to Earthbound viewers, leaving the question of Saturn’s telescopic appearance an enigma.Just as Galileo discovered satellites around Jupiter, Huygens discovered the first known satellite of Saturn (named Titan by John Herschel).This work also includes the first known sketch of the Orion nebula, a cloudy patch in Orion’s sword. In the Starry Messenger, Galileo portrayed new stars visible through his telescope in the central part of Orion, but did not mention the nebula.