Johannes Remus Quietanus or Johann Ruderauf (working 1610 - 1640) was an astronomer and calendar-compiler of Rouffach, Alsace. Though details of his career are sparse, he was one of those who observed the transit of Mercury across the face of the sun in 1631, alerted to the upcoming event in 1629 by his friend and correspondent Johannes Kepler; Pierre Gassendi, however was the only one to publish his observation. Quietanus was the first to employ Kepler's revised Rudolphine Tables in production of a writing calendar.
His Natürliche Practica und Witterung, auf dass Jahr der Geburt Jesu Christi, M.DC.XLII. Im 24. Jahr der beharrlichen Kriegen in Teutschlandt was published by Georg Friedrich Spannseil. He sent copies of his Observationes et descriptiones duorum cometarum (1628) and Oeniponti (1629), intended for Galileo, to Federico Cesi and Giovanni Faber in Rome.