Epitome of Copernican Astronomy and Harmonies of the World (Great Minds Series)

This 1939 translation of small selected portions of Kepler's later works is fairly close to worthless. I read the two chapters from the Epitome, word for word, and it was not a happy experience even though I have degrees in both physics and mathematics. The translation is very poor, and the editorial notes are non-existent even though they are sorely needed.The Harmony of the World is almost totally worthless since it is 99% numerological mumbo-jumbo. (The plural title "Harmonies" is a mistranslation. See Caspar, page 288.) Even the Epitome chapters are about 50% mumbo-jumbo combined with a verbose chatty presentation of some very false inferences about magnetic forces guiding the orbits of the planets.If you want to get to know Kepler's work, there are two excellent books which I have recently read, " Kepler ", the definitive biography by Max Caspar, and " The Sleepwalkers " by Arthur Koestler, a brilliant critical history of astronomy leading up to and including Kepler.Max Caspar's book, page 239, has the following comment about Kepler's intentions for the Epitome."The second plan concerned a textbook, an outline of the Copernican astronomy, the "Epitome Astronomia Copernicanae". Soon after the appearance of the "Astronomia Nova" in 1609 it had occurred to Kepler to present a comprehensive astronomical world picture, as he himself had built it, based on the Copernican theory with his own new discoveries. He wanted to make the shape he had given astronomy suitable for "school benches of the lower classes"."In other words, the Epitome is not one of the original ground-breaking works which first presented Kepler's 3 famous laws. It is a later work presenting the laws to "lower class" school students in the dialogue form which was quite common at that time for rhetorical and educational works.Positive points:1. The diagrams are pretty good. Not much of the Epitome book 5 makes sense without them!2. On page 15, there is an anticipation of Mach's principle which appeared in the late 19th century."The region of the fixed stars supplies the movables with a place and a base upon which the movables are, as it were, supported."This is a flash of brilliance in a paragraph which is otherwise nonsensical.3. On page 17, there is an interesting anticipation of the 19th century luminiferous ether concept."On the contrary, the ether is more rarefied than our air, since it is very pure, being spread over a space which is practically immense."4. On pages 46-47, Kepler notes that the Sun is (probably) just a star, like all the other stars.5. All of Kepler's 3 laws are presented somewhere in the Epitome, with special emphasis on the elliptic orbits with variable speed.6. On pages 63-66 and 94, Kepler raised the possibility of an inverse square law, which could have led him to Newton's momentous breakthroughs. But he immediately rejected this in favour of the inverse linear law because he was not familiar enough with Galileo's kinetic laws. If Galileo had cooperated with Kepler instead of denigrating his work, Newton's accomplishments could have come 50 years earlier!7. On page 96, Kepler states Newton's first law, and there is some discussion of inertia. But Kepler didn't know about second-order differential equations. So he couldn't make the necessary leaps to get the rest of the theory.8. This Kepler sample-book demonstrates very clearly the close intertwining of medieval mumbo-jumbo with the new rationalism which was emerging in Europe during the 17th century. There are many parts of this book which show astonishing modernity in Kepler's thinking, although most of it is pure imagination and bad logic.Epitome book 5, pages 121-164 is somewhat less interesting because it is mostly a collection of tedious computational methods which are long and drawn-out beyond their valuable content.The "Harmony of the world" is pretty much unreadable if you know anything about physics and astronomy. It does have the 3rd Kepler law on page 180, which might have been its first publication. Otherwise, I think it is not worth reading.Because of the poor translation, editorial notes are absolutely essential, but absent, from this book. For example, the word "virtue" means "force" in this book, and "apsides" mean the furthest and closest points of an orbit, and "prehensive force" [not a typo] must mean gravity, I guess. But there are many words which I cannot decipher. This book really needs a vocabulary section for the obscure terminology.And by the way, the book's binding is weak. After reading this book, I have to tape the pages together to prevent it from completely splitting. Three out of five stars for this book is quite generous in my opinion.

Please be advised that, this is not the complete volume. It only contains 2 chapters from Epitome of Copernican Astronomy and 1 chapter from Harmonies of the World.

Absolutely incredible work by one of the greatest geniuses!

In this volume, Kepler combines much of his work into what he believes to be a more accessible understanding of the planetary orbits. I would recommend this book for the serious student of Astronomy, because although it is less demanding than 'Astronomia Nova', it is quite in depth and certain adjustments are made to the Copernican cosmology which the reader must have some familiarity with. A final notice: this edition of the 'Epitome..' is only sections 4 & 5. The prior sections have never been brought into English.

If you want to learn how these guys thought then it's a great learning experience.Otherwise it's chatter.

If you're interested in the universe and music and math and all that that pertains too, purchase this book.