thumb|''Nicolai Copernici Torinensis De revolutionibus orbium coelestium, Libri VI'' (''On the Revolutions of the Heavenly Spheres, by [[Nicolaus Copernicus of civitas Torunensis, Six Books''). Title page of 2nd edition, Basel, ''Officina Henricpetrina'', 1566.]]

'''''De revolutionibus orbium coelestium''''' (On the Revolutions of the Heavenly Spheres''), first printed in 1543 in Nuremberg, is the seminal work on heliocentric theory and the masterpiece of astronomer Nicolaus Copernicus (1473-1543). The book offers an alternative model of the universe to the Ptolemaic system.

==History ==

Copernicus initially wrote up an outline of his system in a short text called the ''Commentariolus''. A physician's library list dating to 1514 includes a manuscript whose description matches the ''Commentariolus'', so Copernicus must have begun work on his new system by that time. However, most historians believe that he wrote the ''Commentariolus'' after his return from Spain, and possibly only after 1510. At this time, Copernicus anticipated that he could reconcile the motion of the Earth to the perceived motions of the planets quite easily, with fewer motions than were necessary for the Alfonsine Tables, the version of Ptolemaic astronomy popular at that time.

Observations of Mercury by Bernhard Walther (1430-1504) of Nuremberg, a pupil of Regiomontanus, were made available to Nicolaus Copernicus by Johannes Schöner, 45 observations in total, 14 of them with longitude and latitude. Copernicus used three of them in ''De revolutionibus'', giving only longitudes, and erroneously attributing them to Schöner. Copernicus's values differed slightly from the ones published by Schöner in 1544 in ''Observationes XXX annorum a I. Regiomontano et B. Walthero Norimbergae habitae, [4°, Norimb. 1544].''
thumb|left|[[Heliocentric model of the solar system]]
Remarkably the manuscript of ''De revolutionibus'' in Copernicus's own hand has survived. (Autograph manuscripts of published major scientific works from this time are rare.) Close examination of the manuscript, including the different types of paper used, has helped scholars to construct an approximate timetable for its composition. Apparently Copernicus began by making a few astronomical observations to provide new data to perfect his models. He may have begun writing the book while still engaged in observations. By the 1530s a substantial part of the book was completed. But he was still completing his work (even if he was not convinced that he wanted to publish it) when in 1539 Georg Joachim Rheticus, a great mathematician from Wittenberg, arrived in Frombork. In 1542, in Copernicus's name, Rheticus published a treatise on trigonometry (later included in the second book of De revolutionibus). Under strong pressure from Rheticus, and having seen that the first general reception of his work had not been unfavorable, Copernicus finally agreed to give the book to his close friend Tiedemann Giese, bishop of Chełmno (Kulm), to be delivered to Rheticus for printing by Johannes Petreius at Nürnberg (Nuremberg). It was published just before his death, in 1543.

The major work of Copernicus is the result of decades of labor. It rewrote Ptolemaic theory for a moving Earth, and incorporates over a thousand years of accounts of astronomical observations of varying accuracy. In its standard English edition, it contains 330 folio pages, 100 pages of tables, and over 20,000 tabulated numbers.

The book is dedicated to Pope Paul III (in a preface which attempts to articulate that mathematics, not physics, should be the basis for understanding and accepting his theory) and is divided into 6 parts ("books"): 

* The first part contains a general vision of the heliocentric theory, and a summarized exposition of his idea on the World.
* The second part is mainly theoretical and describes the principles of spherical astronomy and a list of stars (as a basis for the arguments developed in the subsequent books).
* The third part is mainly dedicated to the apparent movements of the Sun and to related phenomena.
* The fourth part contains a similar description of the Moon and its orbital movements.
* The fifth and the sixth parts contain the concrete exposition of the new system.

''De revolutionibus'' starts with an anonymous foreword stating that the whole work is only a simple hypothesis, implying that it might only be bold speculation. It is misleading to understand the word "hypothesis" in its modern sense, a proposed law or principle that is to be tested by experiment. Rather, the word should be understood as meaning a convenient bit of mathematics not necessarily related at all to reality. The foreword was at the time generally regarded as Copernicus's own idea, until Johannes Kepler showed that it was an addition by the Lutheran philosopher Andreas Osiander. That Osiander had written the preface was certainly common knowledge among astronomers well before Kepler. Johannes Praetorius (1537-1616) wrote on his copy of De Revolutionibus a comment that affirms Osiander as the author of the preface. <ref>Robert Westman, Three Responses to Copernican Theory in The Copernican Achievement - Robert Westman (ed) (1975)</ref>

In his system Copernicus argued that the universe is made up of eight spheres. The outer, eighth sphere consisted of motionless, fixed stars with the sun motionless at the centre. The planets revolved around the Sun in the order of Mercury, Venus, Earth, Mars, Jupiter, and Saturn. The moon however, revolved around the Earth. Moreover, according to him, what seemed to be the movement of the Sun and fixed stars around the Earth was really explained by the daily rotation of the Earth around its own axis. Even with all of his advances, he retained the circular orbits, because of which he was forced to also retain the epicycles of the Ptolemaic system to prove his calculations correct. Nevertheless, the shift from an Earth-centered, to a sun-centered system was very important and raised serious questions about Aristotle's astronomy and physics, despite Copernicus's adherence to Aristotle.

== Reception ==

The book caused only mild controversy at the time, and provoked no fierce sermons about contradicting holy scripture; Osiander's preface, therefore, may have had some success. In 1546, however, a Dominican, Giovanni Maria Tolosani, wrote a treatise denouncing the theory and defending the absolute truth of scripture. Tolosani also claimed that Bartolomeo Spina, the Master of the Sacred Palace, had intended to condemn the theory but had been unable to press the issue because of ill health. 

According to Olivier Thill's 2002 update of a biography written in 1654 by Pierre Gassendi, many  astronomers, theologians and others knew about Copernicus's theory before 1615. Their stance is given as follows:<ref>Gassendi 2002.</ref> 
{| class="wikitable" 
! Copernicans || anti-Copernicans
|-
|Bernard Wapowski, Tiedemann Giese, Johannes Dantiscus, Nikolaus Cardinal von Schönberg, Johann Albrecht Widmannstetter, Georg Joachim Rheticus, Heinrich Zell, Andreas Aurifaber, Achille Pirmin Gasser, Johannes Petreius, Erasmus Reinhold, Johannes Angelus, Petrus Ramus or de la Ramée, Omer Talon, Robert Record or Recorde, John Feild or Field, John Dee, Pontus de Tyard, Leonardo Botallo, Petrus Pitatus, Johannes Stadius, Regnier Gemma Frisius, Cyprianus Leovitius, David Origano or Tost, Nicodème Frischlin, Nicolao Zoravio, Brunone Seidelius, Christian Wursteisen (Urstitius), Erasmus Oswald Schreckenfuchs, Thomas Digges, Nicolaus Neodomus, Michel Eyquem de Montaigne, Valentin Steinmetz, Diego Lopez de Zuñiga or Didacus a Stunica, Giovanni Battista Benedetti, Francesco Patrizio, Bartholomäus Scultetus, John Blagrave, Jonas Petrejus Upsaliensis, Duncan Liddel, Jean-Antoine de Baïf, Bartholomaeus Keckermann, Christoph Rothmann, Joseph Justus Scaliger (the son of Julius C. Scaliger), Paul Wittich, Valentin Otho, Jacob Christmann, Johannes Amos Comenius, William Gilbert, Giordano Bruno, Michael Maestlin, Tycho Brahe, Johannes Kepler, Joseph Gaultier, Nicolas Fabri de Peiresc, Pierre Gassendi, Pierre de Bérulle, Elia Diodati, Matthias Bernegger, Marin Mersenne, René Descartes, Nicolaus Mulerius, etc.
|Paul Eber, Philipp Melanchthon, Martin Luther, Jean Calvin, Giovanni Maria Tolosani, Julius Caesar Scaliger, Jorgen Christoffersen Dibvardius or Dybbard, Francesco Maurolico, Jean Bodin, Guillaume de Saluste du Bartas, Wilhelm Misocacus, Francesco Barozzi or Barocius, Thomas Blundeville, Johannes Laurentius Gevaliensis, Lambert Danneau, Jacopo Mazzoni, François Viète, George Buchanan, Giulio Cesare LaGalla, Giovanni Antonio Magini, Jean-Baptiste Morin, Christopher Clavius, etc. 
|}

Identification of "Copernicans" or "anti-Copernicans" will vary depending on the criteria used. For instance, Gassendi apparently considered Tycho Brahe to be a supporter of Copernicus, even though Tycho plainly believed that the Earth did not move. Tycho performed many of the essential measurements which Johannes Kepler used to advance Copernicus's position.

It has been much debated why sixty years would pass before Copernicus's work would come under serious attack. The alleged reasons range from the personality of Galileo an order from the Pope to take the position that the system was purely hypothesis. After that, ''De revolutionibus'' was placed on the Index of Forbidden Books along with two less important works (but none of Galileo's, at that time). It was not formally banned but merely withdrawn from circulation pending "corrections" which would clarify the status of the theory as hypothesis (nine sentences, by which the heliocentric system was represented as certain, had to be either omitted or changed). Such corrections were prepared by Index until 1758, when Pope Benedict XIV (1740-58) removed the uncorrected book from his revised Index.<ref name="cath-encyc2">"Benedict XIV." ''Catholic Encyclopedia''. http://www.newadvent.org/cathen/04352b.htm</ref> 

A few years after the death of Copernicus, Erasmus Reinhold developed the Prutenic Tables (Prussian Tables, , ), based on Copernicus's observations. Reinhold's Prutenic Tables were used as a basis for the calendar reform instituted under Pope Gregory XIII. The tables were also used by sailors and sea explorers, who during the fourteenth and fifteenth centuries had used the Table of the Stars by Regiomontanus.

thumb|天体运行论
'''《天体运行论》'''（<small>拉丁文：De Revolutionibus Orbium Coelestium</small>）是波兰天文学家哥白尼所著的一本讲述他自己的天文学说的著作。

==簡介==
1506年，哥白尼在回国任教士不久，开始写作《天体运行论》。1512年，哥白尼把他任职城堡西北角的箭楼建为自己的小型天文台，用自制简陋的仪器进行天文观测，计算、研究。他在《天体运行论》一书中所引用的27个观测数据，大部分是在这里记录下来的。约在1536年，哥白尼写成了《天体运行论》，创立了“日心说”。1543年，《天体运行论》出版。由于哥白尼害怕引起各方面的攻击，他在书的序中写明将他的著作献给教宗保祿三世。他认为，在教皇的庇护下，《天体运行论》也许可以问世。除了这篇序之外，《天体运行论》还有另外一篇教士奥西安德尔写的前言。当时哥白尼重病在身，委托这位教士出版发行。奥西安德尔为使这书能安全发行，假造了一篇无署名的前言，说书中的理论不一定代表行星在空间的真正运动，不过是为编算星表、预推行星的位置而想出来的一种人为的设计。这篇前言在半个多世纪的时间里，骗过了许多人。

据说，1543年5月24日，垂危的哥白尼在病榻上见到了从纽伦堡寄来的《天体运行论》样书。他只摸了摸书的封面，便与世长辞了。

==评价==
《天体运行论》出版后很少引起人们的注意。一般人不懂，而许多天文工作者只把这本书当作编算行星星表的一种方法。《天体运行论》在出版后七十年间，曾经遭到马丁·路德的斥责，但未引起罗马教廷的注意。后来布鲁诺和伽利略公开宣传日心说，危及了教会的统治，罗马教廷才于公元1616年把《天体运行论》列为禁书。

《天体运行论》的出版，正式创立了“日心说”。它是天文学上的一次革命，引起了人类宇宙观的重大变革。

恩格斯评价哥白尼的《天体运行论》：