Amazing Astronomy

                                                 Throughout the seven years he spent in Lidzbark-Warminski, Copernicus read several books on the subject of astronomy. Among the sources that Copernicus consulted was Regiomontus's Epitome of the Almagest, which presented an alternative to astrologist Claudius Ptolemy's model of the universe, and significantly influenced his research.
                                                By 1508, Copernicus had begun developing his own celestial model, a heliocentric planetary system. Ptolemy had previously invented a geometric planetary model, which was inconsistent with Aristotle's idea that celestial bodies moved in a circular motion at different speeds around a fixed point, the earth. In an attempt to reconcile such inconsistencies, Copernicus's heliocentric solar system named the sun, rather than the earth, as the center of the solar system. Subsequently, Copernicus believed that the size of each planet's orbit depended on its distance from the sun.
                                               Though his theory was viewed as revolutionary and met with some controversy, Copernicus was not the first astronomer to propose such a theory; centuries prior, in 270 B.C., ancient Greek astronomer Aristarchus of Samos had identified the sun as the solar system's central unit. Aristarchus's ideas were quickly dismissed, however, because Ptolemy's theories were far more eagerly accepted by the influential Roman Catholic Church, which adamantly supported the earth-based solar system theory. Still, Copernicus's heliocentric solar system proved to be more detailed and accurate than Aristarchus's, including a more efficient formula for calculating planetary positions throughout the year.
                                             After moving to the Frombork Cathedral Chapter in the early 1500s, Copernicus further developed his heliocentric model, and went on to design and apply a complex mathematical system for proving his theory. In 1513, his dedication prompted him to build his own modest observatory so that he could view the planets in action at any given time.
                                           Copernicus's observations did, at times, lead him to form inaccurate conclusions, including his assumption that planets' orbit occurred in perfect circles. As German astronomer Johannes Kepler would later prove in the 17th century, planetary orbits are actually elliptical in shape.

 Copernicus Theory :




                                Copernicus' major theory was published in De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), in the year of his death, 1543, though he had formulated the theory several decades earlier.
Copernicus' "Commentariolus" summarized his heliocentric theory. It listed the "assumptions" upon which the theory was based as follows:
"1. There is no one center of all the celestial circles or spheres.
2. The center of the earth is not the center of the universe, but only of gravity and of the lunar sphere.
3. All the spheres revolve about the sun as their mid-point, and therefore the sun is the center of the universe.
4. The ratio of the earth's distance from the sun to the height of the firmament (outermost celestial sphere containing the stars) is so much smaller than the ratio of the earth's radius to its distance from the sun that the distance from the earth to the sun is imperceptible in comparison with the height of the firmament.
5. Whatever motion appears in the firmament arises not from any motion of the firmament, but from the earth's motion. The earth together with its circumjacent elements performs a complete rotation on its fixed poles in a daily motion, while the firmament and highest heaven abide unchanged.
6. What appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve about the sun like any other planet. The earth has, then, more than one motion.
7. The apparent retrograde and direct motion of the planets arises not from their motion but from the earth's. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens."

  Controversy : 
                                    
                                                            Copernicus's written works, Commentariolus and, later, De revolutionibus orbium coelestium (Latin for "On the Revolutions of the Heavenly Spheres"), raised a fair share of controversy. Copernicus's critics claimed that he failed to solve the mystery of the parallax—the seeming displacement in the position of a celestial body, when viewed along varying lines of sight—and that his work lacked a sufficient explanation for why the earth orbits the sun.
                                                          In addition to drawing criticism from scholars, Copernicus's theories incensed the Roman Catholic Church; his model was considered heretical because it was contrary to the Church’s teachings. When De revolutionibus orbium coelestium was published in 1543, just before Copernicus's death, religious leader Martin Luther voiced his opposition to the heliocentric solar system model. His underling, Lutheran minister Andreas Osiander, quickly followed suit, saying of Copernicus, "This fool wants to turn the whole art of astronomy upside down."
                                                          Osiander even went so far as to write a disclaimer stating that the heliocentric system was a theory, not a fact, and add it to the book's preface, leading readers to assume that Copernicus himself had written it. By this time, Copernicus was ailing and unfit for the task of defending his work.
                                                          Ironically, Copernicus had dedicated De revolutionibus orbium coelestium to Pope Paul III. If his tribute to the pope was an attempt to cull the Catholic Church's softer reception, it was to no avail. The Church ultimately banned De revolutionibus posthumously, and the book remained on the list of forbidden reading material for nearly three centuries thereafter.

 Death : 
                                                     In May of 1543, mathematician and scholar Georg Joachim Rheticus presented Copernicus with a copy of a newly published De revolutionibus orbium coelestium. Suffering the aftermath of a recent stroke, Copernicus is said to have been clutching the book when he died in his bed on May 24, 1543 in Frauenburg, Poland.