Miguel A. Granada, Ph.D. (1978), University of Barcelona, is Professor of History of Renaissance Philosophy at the same university. He has published many monographs, translations and articles on Giordano Bruno and the astronomical and cosmological revolution in the early modern period.Adam Mosley, Ph.D. (2000), University of Cambridge, is an Associate Professor in History and Classics at Swansea University. His publications include Bearing the Heavens: Tycho Brahe and the Astronomical Community of the Late Sixteenth Century (Cambridge University Press, 2007).Nicholas Jardine, is Emeritus Professor of History and Philosophy of the Sciences, University of Cambridge. He is author, with Alain Segonds, of La guerre des astronomes, 2 vols (Les Belles Lettres, Paris, 2008).

"Da alle drei Autoren seit Jahren zu den besten Kennern der behandelten Materie gehören, wundert es nicht, dass auch alle Essays höchst lesenswert sind. [..] Der ungewöhnlich Große wissenschaftliche Mehrwert, den das Buch liefert, deutet sich bereits in Miguel Granadas Einleitung an. [...] sowohl durch die sorgfältige zweisprachige Edition als auch aufgrund der hochwertigen wissenschaftlichen Beiträge für alle, die sich mit frühneuzeitlicher Wissenschaftsgeschichte beschäftigen, höchst lesenswert ist."[English translation by Google Translate: "Since all three authors have been among the best connoisseurs of the subject matter for years, it is not surprising that all essays are highly readable. [...] The unusually large scientific added value provided by the book already is evident from Miguel Granada's introduction. [...] both through the careful bilingual edition as well as due to the high-quality scientific contributions for all, who deal with early modern history of science, highly worth reading."-karsten Gaulke, Berichte Wissenschafttsgeschichte, 41 (2018), 194-196."Ultimately, this book by recognized specialists fills an important gap in the history of Renaissance astronomy and cosmology by providing a masterful study of first-hand documents that hitherto had remained unpublished in English." - Jean Seidengart (Université Paris Ouest Nanterre), Journal for the History of Astronomy, 2017, 48(2):251-252. "Readers with an interest in the history of astronomy, scientific method, and cometary studies will profit from reading this book.""The authors are well-known historians of astronomy. [...] The book is thoughtful, well documented, well written, and persuasive. The bibliographies of primary and secondary sources are thorough, as are the indexes of persons, places, and subjects.""This is a model of splendid scholarship on an important aspect of early modern science."- J.R. Christianson in: Isis Volume 106, Number 4 (December 2015): 916-917.

• Preface xiMiguel A. GranadaIntroduction 1Miguel A. Granada1 Christoph Rothmann and Astronomy in Wittenberg 12 Astronomy in Kassel: Landgrave Wilhelm IV and His Programme of Stellar Astronomy 193 The Comet of 1585 and the Dialexis cometae 244 Phases of Composition of the Dialexis cometae 305 Rothmann’s Cosmological Innovations in the Dialexis cometae 366 The Status of Astronomical Hypotheses 557 The Title of the Work 642 Dialexis Cometae qui Anno Christi M.D.LXXXV. mensibus Octobri et Novembri apparuit 67Latin text prepared by Miguel A. GranadaA Discourse on the Comet Which Appeared in the Months of October and November of 1585 67Translation by Nicholas Jardine and Adam Mosley, with annotations by Miguel A. Granada, Nicholas Jardine and Adam MosleyChapter 1. On the Observations of This Comet 78Chapter 2. Concerning the Motion of This Comet in Longitude and Latitude 92Chapter 3. Whether This Comet Had Parallax 104Chapter 4. In Which Sphere This Comet Was 114Chapter 5. Since It Is Commonly Believed That the Spheres of the Planets Are Solid Bodies, How Could the Comet Have Progressedin Them? And What Is to Be Thought on This Question? 120Chapter 6. A Refutation of Some Opinions Concerning Comets; Namely, That They Are Neither Species Appearing without Matter,Nor Perpetual Bodies Together with the Rest of the Stars, Nor Vapours Ignited in the Air 146Chapter 7. The Opinion of the Author about the Matter and Essence of Comets 164Chapter 8. The Uses of the Examination of Comets 178Chapter 9. That That Matter Flowing around the Planets Differs Not at All from Pure Sublunar Air, and Where, Moreover, the ContraryArguments Are Refuted 186Description of the Comet Which Shone in the Year 1596 in the Month of July, but Set Out in a Fuller Form from the Papers of the SameRothmann 2023 Appendices: Related Texts and Translations 207Miguel A. Granada, Nicholas Jardine and Adam Mosley1 Letters of Christoph Rothmann to Landgrave Wilhelm IV of Hesse-Kassel, 1585–1586 2082 Letter of Wilhelm IV of Hesse-Kassel to Heinrich Rantzau, 20 October 1585 2463 Letter of Wilhelm IV to Christoph Rothmann of 18 November 1585, Authorising the Drafting of a scriptum on the Comet 2504 Elias Olsen Morsing’s Account of the Comet of 1585 2524 How to Present a Copernican Comet: The Form and Tactics of Christoph Rothmann’s Dialexis on the Comet of 1585 258Nicholas Jardine1 Introduction 2582 Disciplines: Mathematics vs. Philosophy 2603 Disciplines: Theology 2624 Genres: Dialexis, ‘Critical Doxography’, Historia, Observationes 2675 Persuasive Tactics 2736 Comets as Boundary Objects 2805 The History and Historiography of Early Modern Comets 282Adam Mosley1 1577 and All That: What Every Historian of Astronomy Knows 2822 Historia: Comets, Astronomy, and Historical Astrology 2873 1577 and All That Revisited 3236 A Brief Note on Cometary Parallax 326Adam Mosley1 Tycho, Regiomontanus, and the Problems of Parallax 3262 Rothmann and the Parallax of the Comet of 1585 3343 Conclusion 339Bibliography 341Index of Persons 367Index of Places 373Index of Subjects 374