   The Narratio prima was written in 1539 and took the form of a letter to Johann Schöner announcing Copernicus’s findings and describing the contents of the Revolutions. He dealt with such topics as the motions of the fixed stars, the tropical year, the obliquity of the ecliptic, the problems resulting from the motion of the sun, the motions of the earth and the other planets, librations, longitude in the other five planets, and the apparent deviation of the planets from the ecliptic. He asserted that the heliocentric universe should have been adopted because it better accounted for such phenomena as the precession of the equinoxes and the change in the obliquity of the ecliptic; it resulted in a diminution of the eccentricity of the sun; the sun was the center of the deferents of the planets; it allowed the circles in the universe to revolve uniformly and regularly; it satisfied appearances more readily with fewer explanations necessary; it united all the spheres into one system.  Rheticus added astrological predictions and number mysticism, which were absent from Copernicus’s work.