Talk:Johannes Kepler/Archive 1

message: someone has defaced the page. Specifically the area about his death. Just thought I should let someone know.
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Removed.  It's not clear that previous generations of astronomers had been content to accept authority of ideas.  Kepler had new data which other astronomers had, and it took him 20 years to process it all.
: whereas previous generations of astronomers had been content to accept the authority of ideas from previous generations
----
Removed reference to God.  The people that initially came up with the idea that planets moved in circles were the Greeks who did not believe that planets moved in that way because God wanted them to.  They were polythestic.  The reasons for circles came from Plato, which got absorbed into Christian theology, but that's a whole other article.
Also emphasized the fact that before Tycho, all the data suggested that the planets did move in circles, and that showing that they weren't circles was not obvious (it took Kepler decades.)
Roadrunner
Are the two titles The Cosmic Mystery and Misterium Cosmographicum the same book ? It's a bit  confusing with alternating Latin and English translated titles.Norwikian 10:34, 4 Oct 2003 (UTC)
replies: text: They're the same.  Caesar Lexicorum, 00:46, 30 December 2005 (UTC)
thread_title:  comments 

message: Removed the 'See also" link pointing to his laws of planetary motion. The link was superfluous, as there was already a link to that topic within the body of the text!  Eilthireach 03:57, 27 Mar 2005 (UTC)
thread_title:  The 'See also' link 

message: When I came across the article earlier today, it was extremely unbalanced between his mysticism and his scientific work. Of course these are modern categories, but from the amount of space devoted to them, it came across as though his speculation about the platonic solids were somehow ten times more important than his laws of planetary motion! Part of this may be simply because the treatment of his laws of motion was in the Kepler's laws of planetary motion article, but I thought it was just plain goofy. Given some of the controversy there's been over astrology-related articles, I may also be hypersensitive to what I see as attempts by believers in astrology to push a POV that legitimizes astrology, and blurs the line between science and pseudoscience. I've beefed up the discussion of Kepler's laws with a couple of figures and more text. (Most of this is taken directly from a copylefted book I wrote.) Although this may be seen as duplicating the article on Kepler's laws, it is much shorter and less mathematical, so I think it's appropriate to have it in here.--Bcrowell 5 July 2005 16:35 (UTC)
:It is also hard to understand why so much space is devoted to his nonsensical books whereas there's no mention of Astronomia nova. Bambaiah 13:37, July 12, 2005 (UTC)
::Certianly mathamatical observations outway mystologicalb observations? no?--Hello'from'SPACE 00:12, 15 November 2005 (UTC)
thread_title:  Balance 

message: There a request for Kepler's Third Law from Wikipedia:ACF Regionals 2000 answers
If this is another name for a page that already exists could someone more knowledgeable than me make a redirect.  Or if not could some make an article.--BirgitteSB 15:55, July 12, 2005 (UTC)
:Hi -- The article you refer to has been nominated for deletion. No, there should not be a separate article on the third law. It's covered here.--Bcrowell 17:02, 12 July 2005 (UTC)
thread_title:  Kepler's Third Law 

message: There is a very recent paper entitled "Kepler's Equations : A Kinematical Deduction" by Raul Nunes (a copy of which can be downloaded from http://ThreeBirds.com.br/KE.pdf) which contains a new purely kinematical deduction of Kepler's equations for all types of conics.  It also includes a lot of bibliographic references about Kepler's works and life.
I have added some information about exactly how Kepler was able to use Tycho's observational data to deduce the orbit of Mars and thus his various laws. Peter Maggs 22:12, 15 October 2005 (UTC)
thread_title:  Kepler's Equations 

message: Is there an "s" in the name of the book? I'm asking because someone chopped the "s" out in the on Harmonices Mundi article. Curiously, each of these get a lot of Google hits. See here for the hits without the "s", and see  here for the hits with the "s". It's not clear to me which is right. (I'm posting this here because this article seems to have more traffic.) --A bit iffy 08:16, 18 October 2005 (UTC)
replies: text: The anniversaries section today says that on this day some years ago, Kepler discovered the third law of planetary motion. Huh? You don't discover something like that until years, possibly decades of observing data or reading collected data. Is March 8 the day he settled on its final form? The day he first proposed it? Thought of it? The day it was published in a journal? They day it was submitted to a journal? No discovery of a scientific law happens all in one day. The article on Kepler doesn't specify which. Can we clarify this entry please? 24.243.188.42 02:07, 8 March 2006 (UTC)
replies: text: Google shows that the third law of planetary motion was published in 1619 in Harmonice Mundi. The Wiki article states that it took 2 decades to find the form of the 3 laws. This would make March 8 the anniversary of the day he settled on its final form -- by extensive number crunching (two decades worth). --Ancheta Wis 05:06, 8 March 2006 (UTC)

text: Note: The Kepler article Revision as of 08:36, 9 March 2003 stated the initial March 8, 1618 discovery (and the confirmation on May 15, 1618). But it has apparently been dropped from the article. By the policy of Selected anniversaries we need to reinstate this fact into the article. --05:29, 8 March 2006 (UTC)
thread_title:  Harmonices Mundi or Harmonice Mundi? 

message: Kepler's posthumous 1634 book Somnum is sometimes called SF. (So is The Divine Comedy...)  Trekphiler 01:01, 30 December 2005 (UTC)
thread_title:  First SF writer? 

message: PhilipC, I've reverted your changed of "Lutheran" to "German" in the first sentence, as Lutheran was much more key to his identity than German, since this was the time of the Holy Roman Empire and he worked in both present-day Germany and Austria.  It may be appropriate to include something about Germany later in the intro if you can find a way to do it elegantly.--ragesoss 01:06, 31 December 2005 (UTC)
replies: text: Actually, a "Lutheran school" isn't too far off.  Even though it wasn't peculiar to those disciplines, being a Lutheran academic at that time meant something very different (and perhaps more coherent) than, say, being a Catholic or Calvinist (perhaps on par with "Jesuit").  The education system and the "Philippist" (after Melancthon) educational philosophy were important for the way Kepler thought about the world, and the way he did his (what we would call) science.  The Barker and Goldstein reference goes into some detail about this.  But your concerns about encyclopedic convention are significant.  Let's wait and see if anyone else chips in or comes up with a better way to reword the intro while maintaining the proper emphasis and flow.  Thanks, PhilipC.--ragesoss 00:56, 1 January 2006 (UTC)

text: I grant that German may be a valid descriptor, but I think Lutheran is still far more central for his biography.  Your revision also makes the sentence somewhat awkward.  I'll try to think of a way to include German in the first sentence without disrupting it.--ragesoss 21:08, 18 January 2006 (UTC)
thread_title:  Lutheran vs. German in intro 

message: Theodore7,
I've reverted your recent edits to Kepler. While I appreciate you point about the importance of astrology, this article was already clear about it being a significant part of Kepler's professional work. Many of the people in the article (Tycho, Galileo) were also astrologers, but in the context of this article "astronomer" or "astonomer/astrologer" are fine concise descriptions the way they are, and should not be simply replaced with "astrologer." Replacing "Lutheran mathematician, astrologer and astronomer" with simply "astrologer" is the kind of edit that requires discussion and consensus. I hope you will try to contribute something substantial (and sourced) to Kepler article, but please use the talk page to argue your point before making any more such changes--ragesoss 14:46, 7 January 2006 (UTC)
thread_title:  astrology edits 

message: I've started an approach that may apply to Wikipedia's Core Biography articles: creating a branching list page based on in popular culture information.  I started that last year while I raised Joan of Arc to featured article when I created Cultural depictions of Joan of Arc, which has become a featured list.  Recently I also created Cultural depictions of Alexander the Great out of material that had been deleted from the biography article.  Since cultural references sometimes get deleted without discussion, I'd like to suggest this approach as a model for the editors here.  Regards, Durova 15:42, 18 October 2006 (UTC)
replies: text: Very few biography subjects warrant a separate page just for cultural references. Separating them detracts from the completeness of the article and forces the reader to follow a link for information that belongs in the same article. Cultural references frequently get deleted because they are unsourced or are too trivial to be meet encyclopedic standards. Finell (Talk) 16:36, 18 October 2006 (UTC)
replies: text: I agree that very few biography subjects warrant a separate page, which is why I've posted this suggestion only to Wikipedia's core biographies.  Because, as you say, these references often get deleted I've relied on the core biographies list rather than the size of a current cultural references section to suggest this solution.  If you think it's inappropriate in this case I'll defer to that opinion.  However, I would like to suggest that even "trivial" references can become useful educational tools for important biographies.  In my music history class (dare I say at Columbia University?) a good portion of the class thought they had never heard Richard Wagner's music until the instructor reminded them of the soundtrack to Apocalypse Now and the Warner Bros. cartoon "What's Opera, Doc?"  Respectfully, Durova 05:33, 20 October 2006 (UTC)
thread_title:  [[Cultural depictions of Johannes Kepler]] 

message: It would be nice to include a plot of Tycho's data Kepler used in formulating his laws. I have the raw data (from "Brahe, Tycho. Tychonis Brahe Dani Opera Omnia (in Latin). Vol 1-15. 1913-1929. Edited by I.L.E. Dreyer.") and created a plot using R (see below). I would like to add some regression analysis in order to highlight the periodic nature of the data. This can be a bit tricky with R for non-linear fits. If anyone knows an easy way, let me know and I can recreate the plot. I can also upload the raw data somewhere, if someone would like it?--Thorwald 04:35, 5 November 2006 (UTC)
thread_title:  Tycho Brahe's Mars Observations - plot 

message: Capitalization of the Latin book titles in this article is inconsistent. Is it not true that conventionally only the first word and proper nouns in Latin titles should be capitalized? In any case (sorry about that) let's set a convention and conform to it.Myron 13:53, 16 November 2006 (UTC)
thread_title:  Caps on book titles? 

message: I've re-written this article, mostly from scratch.  Any feedback will be greatly appreciated; I would like to work this into a Featured Article.--ragesoss 06:59, 16 December 2006 (UTC)
replies: text: I think the article is pretty clear about him being an astrologer, though I agree that the ways in which he used astrology in his personal life are telling and could due for some elaboration.--ragesoss 05:22, 18 December 2006 (UTC)
thread_title:  Total re-write 

message: Unfortunately the article is fundamentally defective from the philosophy of science point of view, with its central interest in the logic of scientific discovery.  And as the Wikipedia article  on history of science used to tell us, the very rationale of the history of science is to provide a testbed for the theories of philosophy of science such as its theories of the rationale of theory change. But what it does not tell us is that history of science is itself already constructed and biassed according to various philosophies of science, and Ragesoss adopts standard mistaken inductivist and revolutionist philosophies of the standard mistaken positivist theory of a scientific revolution. Here I make just three major corrective points.
*(1)	Kepler's kinematical laws of planetary motion are most certainly not the foundation of Newton's gravity theory: As Duhem, Popper, Feyerabend and others have periodically pointed out, the planets do not move in ellipses and Kepler's laws are therefore false according to Newtonian dynamics. If they were true, then Newton's theory of mutual gravitational attraction and his planetary gravitational perturbation theory must be false. Newton's astro-dynamics and theory of gravity contradicted Kepler's and falsified his kinematical laws. In fact  whilst writing the Principia Newton was greatly concerned with falsifying Kepler's Rudolphine Tables with such as the non-elliptical gravitationally perturbed motion of Saturn. In fact refuting the Rudolphine Tables based on Kepler's laws was something of a sport amongst English astro-physicists. Thus the opening claim that “Kepler's laws would be the foundation of Isaac Newton's theory of universal gravitation”  must be deleted as illogical nonsense.
*(2)	Circular orbits were not replaced by ellipses:   One of the sillier and scientifically ignorant positivist myths of a scientific revolution is that Kepler successfully replaced circular planetary orbits with elliptical ones, which was supposedly revolutionary. But on the one hand since Appollonian epicycles in antiquity, planetary orbits were not circular but were at most epitrochoid, as even the Wikipedia article on the epicycle points out, and planetary orbits were most certainly not thought to be circular immediately before Kepler's astronomy. And on the other hand planetary orbits are not elliptical according to Newton's dynamics. 'From circles to ellipses' is a total myth. Of course Galileo and Newton and others supposed planetary orbits to be circular or indeed elliptical as simplified models posited for specific theoretical purposes. But false kinematical assumptions made for hypothetical dynamical modelling purposes should not be confused with reality.  Unfortunately the article has been influenced by this basic error. Thus such false claims as the following two and others must be deleted or corrected:
"Since antiquity, it was assumed a priori that the natural motion of planets was circular; retrograge motion was acccounted for, in Ptolemaic astronomy, through circular epicycles, ..."
"All earlier astronomers, including Copernicus, conceived of the planets as dense spots within a system of orbs, spherical shells that rotated to produced the observed motion of planets; a planet's distance from its center of rotation based on many points was assumed constant."
In general  I presume it is an interesting unanswered question whether the orbital trajectories of the solar planets are best approximated on average by a circle, ovoid, epitrochoid, ellipse or any other closed curve, noting Newton's observation that in humanly scientifically unfathomable complex reality, they are not recurrent closed curves at all, since in dynamically complex reality no planet repeats its orbit.
*(3)	Kepler's major historical achievement lay in producing a scientifically progressive Aristotelian inertial astro-dynamics:    Kepler's astro-dynamics from his Astronomia Nova onwards explodes the standard positivist narrative of an astro-dynamical revolution according to which a heliocentric revolution in kinematical astronomy precipitated an anti-Aristotelian revolution in dynamics because a moving earth necessitated an 'anti-Aristotelian' dynamics in which such motion does not require an external mover.  But this narrative is obviously logical nonsense inasmuch as there is no logical reason why heliocentrism cannot be associated with a dynamics that requires external movers for such motion, and indeed it was. For both Copernicus and Kepler posited external movers of the planets - Copernicus posited the planets were moved by rotating celestial spheres within which they were embedded, Kepler posited the planets were pushed around by the sunspecks of the rotating Sun, and Descartes that they were swept around by vortices, and heliocentrism was accepted long before the Thomist-Keplerian doctrine of inertia that bodies inherently resist ALL motion was rejected in favour of Newton's minor revision of it that they resist all motion EXCEPT uniform straight motion. In particular Kepler adopted a Thomist 'inertial' variant of Aristotelian dynamics, according to which all bodies universally have a non-gravitational inherent resistance to motion proportional to their mass 'm', and whereby v α F/m. The radical historical importance of Kepler's 'inertial' astro-physics may be that it was the first astro-physics to theoretically anticipate novel facts before they were observed, for it successfully predicted the dramatic novel facts that the Sun and planets with satellites rotate, first confirmed by rotating sunspots in 1609(?) by the telescopic observations of Kepler's research assistant, John Fabricius. Because on Kepler's Aristotelian inertial dynamics orbiting satellites must be pushed around by something, he therefore posited the Sun and planets with orbiting moons such as Jupiter  must all rotate in order to push their satellites around somehow. These were apparently the first successful theoretical novel predictions of heliocentric astro-physics, and on the Huyghens-Leibniz criterion that the greatest commendation of a hypothesis next to absolute proof is that it successfully predicts novel facts, they might explain the major conversion to heliocentrism soon thereafter. It is a major defect of the article that it entirely omits any mention of this historically highly important scientific development achieved by Kepler and contains no mention whatever of sunspots and of the dramatic theoretical significance of rotating sunspots. Arguably rotating sunspots provide the grail no historian of science has yet discovered, namely what makes the heliocentric revolution rational.
I shall leave you some time to revise the article yourself or else rebutt my criticism before I make any corrective deletions/revisions. But to make clear, you have my constructively critical support in making this a featured article. Whilst I cannot agree with Hegel and Popper that Kepler's scientific achievement was greater than that of Newton, I certainly agree they were far nearer the truth than the standard positivist account, if not for reasons they realised. For without Kepler's notion of 'inertia', rejected by Galileo but most keenly noted and critically revised by both Descartes and Newton, we would never have had Newton's historically crucial inertial dynamics. Season's Greetings. Logicus 20:40, 26 December 2006 (UTC)
replies: text: Testing the Rudolphine Tables: Re point (1) above, it seems that on the one hand the 1639 transit of Venus, specifically observed by the English astronomer Jeremiah Horrocks for that critical purpose, was regarded as a falsification of the Rudolphine Tables because they did not predict Venus would appear in the sun’s disc, and on the other hand a confirmation of Lansberg’s competing astronomical tables based on epicyclical astronomy which did predict it. [See Dreyer.] Logicus 15:44, 7 January 2007 (UTC)
thread_title:  Logicus Criticisms 

message: Logicus's discussion minimizing the relation between Kepler's laws and Newton's theory of gravitation raises a good point and then takes it too far.  Admittedly Keplerian elliptical orbits only apply rigorously in a simple two-body problem, and Newton spent part of his Principia struggling to deal with motions involving three or more bodies.  Furthermore, as Curtis Wilson long ago pointed out, Newton was concerned over the lack of precision of Kepler's laws ("Newton and Some Philosophers on Kepler's 'Laws'," Journal of the History of Ideas, 35 (1974): 231-258).
However, Newton deduced the inverse square law in the annus mirabilis of 1665 from considerations of the motion of the Moon and "from Kepler's rule of the periodical times of the Planets being in sesquialterate proportion of their distances from the center of their Orbs."  (Westfall, Never at Rest, pp.143, 152).  In 1684 Newton's manuscript De motu corporum in gyrum demonstrated all three of Kepler's laws from physical principles (Westfall, p. 404)  Newton's Principia (1687) expands on those, including a demonstration that bodies moving under an inverse square force travel in paths described by conic sections, of which Kepler's elliptical orbits provide a special case(Principia, Book I,Sect. III, Prop. XI, Prob. VI; Prop. XII, Prob. VII; Prop. XIII, Prob. VIII; Prop. XVII, Prob. IX) a demonstration that bodies moving under a centrally directed force sweep out equal areas in equal times (Principia, Book I, Sect. II, Prop. I, Th. I; Prop. II, Th. II) and demonstrations that Kepler's 3/2 power law follows from inverse square gravitation (Principia Book I, Sect. III, Prop. XV, Theorem VII) and that Kepler's 3/2 power law is inconsistent with Cartesian vortices (Principia, Book II, Prop. LII, Theorem XL, Scholium).  Addressing the more complex case of many bodies, Newton found that these bodies "may move among themselves in elipses; and that the radii drawn to the foci describe areas very nearly proportional to the times" (Principia, Book I, Proposition LXV, Theorem XXV).  To speak of perturbed elliptical orbits does not sound at all like a falsification of Kepler's theory.
:Theres a highly readable account of these demonstrations in Feynman's Lost Lecture - The Motion of the Planets Around the Sun by Goodstein & Goodstein - if you're interested! Fizzackerly 16:17, 26 February 2007 (UTC)
replies: text: Logicus comments: Thanks for all this, and will respond as most appropriate. But since at least you do not disgree that Kepler's laws were not the foundation of Newton's gravity theory, I shall delete the logically mistaken claim that they were. Logicus 17:04, 29 December 2006 (UTC)
replies: text: Sed contra.  I thought I made it clear that one of Newton's two original derivations of his law of gravity was based on Kepler's third law and that the third law (as well as the other two) continued to play an important role in Newton's Principia.  That's pretty clear evidence that Kepler's laws were one of the foundations of Newton's gravity theory.  I don't want to get into a revert war, but Kepler's influence on Newton is an important element of Kepler's significance and should remain in the article. --SteveMcCluskey 17:43, 29 December 2006 (UTC)
thread_title:  Kepler's Laws and Newton 

message: "The very idea of an orbit, a trajectory through space, may have been the most revolutionary aspect of the New Astronomy. All earlier astronomers, including Copernicus, conceived of the planets as dense spots within a system of orbs, spherical shells that rotated to produced the observed motion of planets; a planet's distance from its center of rotation based on many points was assumed constant. [17]"
This paragraph must be deleted. Contrary to its first sentence, Field 1988 [See Further References] tells us Kepler "does not use the word orbis in a way which would allow us to translate it as 'orbit' i.e. the planet's actual path in space." [p86, Field 1988] And contrary to the second sentence, (i) Tycho's geocentric astronomy did not 'conceive of the planets as dense spots within a system of orbs' since it abolished the solid orbs, and (ii) a planet's distance from its center of rotation based on many points was not assumed constant at least since epicyclic astronomy.Logicus 19:13, 2 January 2007 (UTC)
replies: text: I'll have to re-check out the book I had cited for that, and compare some other sources.  I know that Andersen, Barker and Chen, among others put a lot of emphasis on Kepler's orbits being revolutionary, but re-reading what I wrote it seems a bit off (especially with respect to the Tychonic system, as you point out).  Something should definitely be said about the emergence of the orbit concept, balancing the different interpretations.--ragesoss 17:18, 6 January 2007 (UTC)
replies: text: Logicus to Ragesoss: In general re your ideological interest here in finding something revolutionary in the astronomy of Kepler's Astronomia Nova, the only significantly historically novel aspect of it I am aware of is that it was the first development of the Aristotelian inertial dynamics developed by Averroes and Aquinas for a heliocentric model. But it was not thereby revolutionary nor in any other respect I am aware of. But of course in the advertising industry and revolutionist historiography of science everything is 'a revolutionary new product', and so possibly Kepler's orbits are for such as revolutionists Andersen, Barker & Chen. But obviously such claims without serious proof are not to be taken seriously. For clearly the concept of a planet having a non-circular re-entrant closed curve trajectory was not original to Kepler; see for example the ovoid orbit for Mercury depicted in the 1558 Rheinhold edition of Peuerbach's astronomy on p341 of Gingerich's 1993 book The Eye of Heaven cited in the Bibliography. And since the notion of a planet performing a trajectory in space without being embedded in an orb is obviously also pre-Kepler and indeed ancient, why bother with such an abstruse issue in an article on Kepler ? Inasmuch as the purpose of history of science is to help determine the logic of scientific discovery and development, identifying exactly what was specifically historically novel in Kepler's work and its problem-solving rationale by means of critical logical thinking is surely more important than repeating the unreliable illogical nonsense spouted by historians of science about what was. Logicus 19:06, 9 January 2007 (UTC)
replies: text: First of all, I deny any ideological interest in finding something revolutionary in Astronomia Nova; I simply wrote this article based on the sources I was most familiar with, on the assumption that others could help balance the article in areas of historical dispute.  Granting that the source I had used might not be significant enough to warrant inclusion, the idea of Astronomia Nova being revolutionary is a strong and recurring idea in the historiography; mistaken or not, it's an issue that needs to be in the article (along with contrary views attributed to other historians).  It is beyond the proper domain of a Wikipedia article to make the kind of decisions about which experts are right and which are wrong that you seem to be asking for.  It's not our place to investigate the logic of scientific discovery, but simply to provide a biography of Kepler, based on existing literature by experts.--ragesoss 19:20, 9 January 2007 (UTC)
thread_title:  Logicus Delete re Orbits 

message: Well, I read this article and found it to be exemplary, but let's go through the motions anyway
# Well written -pass
# factually accurate and verifiable - pass
# broad in coverage - pass
# neutral - pass
# stable - pass
# images - pass
Overall, I'm very happy to make this a Good Article. Deyyaz [ Talk | Contribs ] 18:31, 6 January 2007 (UTC)
replies: text: I wouldn't be so sure about the stable part, as it just went through a complete re-write and there are there are lots of bugs to work out, but thanks.--ragesoss 18:40, 6 January 2007 (UTC)
replies: text:  As yet Logicus cannot give passes at least for 2, 3 and 4, but works towards improvements to that end. Logicus 19:08, 10 January 2007 (UTC)
thread_title:  GA nomination 

message: The interaction of the observations of the transits of Venus and Mercury with Keplerian theory raises important issues in the reception of scientific theories.  The only historian cited as describing the event, Owen Gingerich, saw the transit of Mercury as a fulfillment of Kepler's prediction.  The article's current claim that these observations showed Kepler's elliptical orbit laws were false implies that this was recognized by the observers, when in fact this is not the case.
:In the case of the transit of Mercury in 1631, Kepler had been extremely uncertain of the parameters for Mercury, and advised observers to look for the transit the days before and after the predicted date.  Pierre Gassendi observed the transit on the date predicted, a confirmation of Kepler's prediction.  Gassendi himself was less concerned with planetary theory than with the size of Mercury, which he found to be much smaller than expected.  Planetary astronomers, when considering his observation, used it to improve the values of the inclination of Mercury's orbit to the ecliptic and the location of the orbit's nodes, rather than to reject any astronomical theory. (Albert van Helden, "The Importance of the Transit of Mercury of 1631," Journal for the History of Astronomy, 7 (1976): 1-10.)
:Jeremaiah Horrocks, who observed the 1638 Venus transit, had used his own observations of Venus to adjust the parameters of the Keplerian model, predicted the transit, and then built apparatus to observe the transit.  He remained a firm advocate of the Keplerian model. ("A Monument to Jeremaiah Horrocks," Nature, July 9, 1874, p. 190; Wilbur Applebaum and Robert Hatch,"Boulliau, Mercator, and Horrock's Venus in sole visa: Three Unpublished Letters," Journal for the History of Astronomy, 14(1983): 166-179) 
What we're looking at here is an interesting case study of the reception of a scientific theory – of Kepler's laws.  Perhaps the best way to deal with this is by removing the paragraph on the transit observations and adding a new section on the reception of Kepler's astronomy in the course of the Seventeenth century.  There are two recent articles, which I haven't seen, that should have more to say about this matter:
*Allan Chapman, "Jeremiah Horrocks, the transit of Venus, and the 'New Astronomy' in early seventeenth-century England", Quarterly Journal of the Royal Astronomical Society, 31 (1996): 333-357. 
*Wilbur Applebaum, "Keplerian astronomy after Kepler: Researches and problems," History of Science, 34 (1996): 451-504.
--SteveMcCluskey 16:13, 29 January 2007 (UTC)
replies: text: The article on transits of Venus says: "Johannes Kepler was the first to predict a transit of Venus in 1631, but no one observed it, because Kepler's predictions were not sufficiently accurate to predict that the transit would not be visible in most of Europe." This contradicts the assertion that Gassendi observed it. Does anyone know how these can be reconciled? Rjm at sleepers 10:43, 15 July 2007 (UTC)
replies: text: Apparently Gassendi observed the transit of Mercury, but not Venus. I have edited the article to this effect. Rjm at sleepers 07:24, 19 July 2007 (UTC)
thread_title: Gassendi, Horrocks and the transits

message: Logicus's proposed assessment of the role of Kepler's ellipse law, that "it is a fallacy to say, as some commentators and other encyclopedias have, that planetary orbits were held to be circular before Kepler but elliptical thereafter." is both ambiguous and inadequate.  It is ambiguous as it seems to propose (here I follow the talk page) each of the following negative statements:
* Before Kepler it was not held that planetary orbits were circular.
* After Kepler many people held that planetary orbits were circular.
* After Kepler, no one adopted elliptical orbits, because the orbits weren't really elliptical
But negative statements are inadequate for an encyclopedia.  We are trying to tell our readers the general consensus among historians of the significance of Kepler's work.
As I see it the historians' consensus involves at least two points:
* A shift from a geometrical to a physical mode of analysis. (I won't deal with that issue here).
* A shift from the use of circles to the use of ellipses as the ruling geometrical/philosophical model.
The final point does not imply either that the paths of the planets were actually circular or elliptical, but only that circles or ellipses formed the reigning paradigm.
*As to circles, the consensus is consistent with the fact that in the medieval model the planets followed compound circular motions, both 
** in the more qualitative discussions in the theorica planetarum literature and.
**in the mathematical geometrical models used to compute astronomical tables
*As to ellipses: the consensus is consistent with the fact that after Kepler
**ellipses did not immediately replace the circular paradigm since
***some philosophers (Galileo, Descartes, Huygens) continued to advocate circles and
***some astronomers used circular mechanisms as a way to mathematically approximate Kepler's ellipses.
**Newton and subsequent astronomers used ellipses even while they recognized that the elliptical orbits were perturbed and only approximated ellipses.  For continued use at the present see Osculating orbit.
The cutting point here is that Logicus maintains that if a planet's motion isn't exactly a circle, circularity is irrelevant; if an orbit isn't exactly an ellipse, we can't speak of an orbit as elliptical.  An analogous approach is found in Logicus's earlier assertion that the observation of the 1631 transit of Mercury, which Gingerich described as a fulfillment of Kepler's theory, is seen by Logicus as a falsification of Kepler's elliptical laws and Rudolphine Tables.
Logicus seems to maintain that any discrepancy, no matter how small, leads to falsification, while most historians of science – and many philosophers – see such anomalies as a normal part of scientific activity.  Imre Lakatos pointed out the problems of such strict falsifcationism in a 1973 exchange with Alex Bellamy (M. Motterlini, ed., For and Against Method, p. 90):
::According to the Logic of Scientific Discovery (and, Alex, I think you will find it very difficult to refute this), the rationality of the scientific enterprise... depends  on cutting the propositions into two: basic statements and theoretical statements; falsifiable statements and unfalsifiable statements....
::Moreover, I pointed out—and this is a matter of historical fact, not logic—that all theories are anomaly-laden.  That means that there are always problems in any theory which have to be shelved.  If all theories are born refuted, then it is perfectly clear that all theories are falsified right at the beginning....
Since all theories are born anomaly-laden, historical discussion involves describing how scientists actually deal with these anomalies rather than how they should deal with them if they were following a particular philosophical model.  As an example, consider that while Newton fully recognized the imperfection of Kepler's ellipses, he still opened his demonstration of planetary motion and its perturbations with the statement: "The planets move in ellipses which have their common focus in the centre of the sun; and by radii drawn to that centre, they describe areas proportional to the times of description" (Principia, Book III, Proposition XIII, Theorem XIII).
History is a subtle study and does not employ philosophy's simple logical dichotomies, since they are seldom found in science as it is actually practiced.  Perhaps this explains why Logicus heaps abuse on so many historians.  I will revert Logicus's proposed assessment and hope we can come to a new one that reflects the complexity of history.  --SteveMcCluskey 23:07, 26 January 2007 (UTC)
replies: text: Since Ragesoss has restored my version to this disputed introduction, I've added a few references and a citation to Stephenson on Kepler, astronomy, and physics, replacing the troubling quotation from Sagan discussed above.  --SteveMcCluskey 14:07, 28 January 2007 (UTC)
thread_title: Logicus's Assessment

message: In the article it says: "Kepler broke off his friendship with Paulin shotly after finding out he was in fact a homosexual" I couldn't find any sources verifying this. --129.13.186.2 17:58, 27 January 2007 (UTC)
thread_title:  Homosexual 

message: A Request for Comment (RfC) has been opened at Wikipedia:Requests for comment/Logicus on Logicus's editing on this article and its associated talk page.  
Anyone is welcome to add comments by certifying the dispute, by endorsing either the posted summary or responses to it, or by submitting their own perspective on the events described.
--SteveMcCluskey 02:01, 6 February 2007 (UTC)
thread_title:  RfC on Logicus's editing 

message: One issue brought up at FAC is images, and the uneven spacing of them.  Anyone have access to images related to Harmonices Mundi, Epitome, or witch trials, or anything else for the unillustrated sections?--ragesoss 03:09, 14 March 2007 (UTC)
thread_title:  Images 

message: The term "lutheran" is confusing here, because the seminary Kepler joined was state-run. The dukes of Wuerttemberg were very famous for their advanced education system which the "Maulbronn seminary" was part of, as well as the Tübingen Stift.
To qualify for this elite school system, one had to qualify by passing a state-wide exam, the so-called "Landexamen". Only talent and knowledge was decisive to be recruited, not noble or rich ancestry. 
The aim of that school system was to educate the eventual Wuerttemberg civil servants (higher ranks) and the priests of the Wuerttemberg State Church.
Other famous students of that education system were, i.a., the german poets and writers Friedrich Hölderlin and Hermann Hesse.
Therefore, I will change "Lutheran" to Württemberg state-run". —The preceding unsigned comment was added by Pfg (talk • contribs) 15:42, 19 March 2007 (UTC)
replies: text: It's true that it was a state-run school, but it is relevant that it was a Lutheran seminary; after all, the religious aspect is fundamental to being a seminary, and the Württemberg State Church was a Lutheran one.  I'm adding "Lutheran" back in after "state-run"--ragesoss 15:50, 19 March 2007 (UTC)
thread_title:  Lutheran education system 

message: Despite his desire to become a minister, near the end of his studies Kepler was recommended for a position as teacher of mathematics and astronomy at the Protestant school in Graz, Austria (later the University of Graz). He accepted the position in April 1594, at the age of 23.
It is impossible that Kepler was 23 when he took up the position at Graz, as he was born in December and he arrived in austria in April.
                 1594 - 1571 = 23
But as he arrived in April and not after his birthday Kepler was only 22. Maybe the other dates and corresponding ages should be checked over
Mike
220.235.175.166 14:42, 2 April 2007 (UTC)
thread_title:  Bad Dates and Ages 

message: I have read some of your posts and the homosexual topic was interesting because it's not true. I am related to Johannes Kepler. I found this out from my grandmother and I'd never even heard of him. Bye.
Kristina —The preceding unsigned comment was added by 66.185.6.93 (talk) 15:39, 10 April 2007 (UTC)
thread_title:  Kepler 

message: “Planets sweep out equal areas in equal times.”  Why would the planet care???  I mean, this is so abstract and mathematical.  (And I know a planet doesn’t actually care, but why would an inanimate object act in this fashion?)
What I’m asking for is to explain the whole idea more conceptually.  For example, “A planet is in continuous free fall, and goes faster as it nears the Sun and then moderately sling-shots out, and slows due to the Sun’s continuous gravitation pull, thusly beginning its return trip at a certain point.  The result is an equilibrium with a modest elliptical orbit.”
And if I’m mistaken, please correct me.  And if Kepler didn’t quite take it this far, then maybe we can tell how his theories developed over the next hundred years, for he was a highly influential figure in the history of science.  (And as our article says, he was also a mystical guy, but an honest experimentalist, he really did compare his theories to the available data.)   FriendlyRiverOtter 06:22, 11 June 2007 (UTC)
thread_title:  Planets in continual free fall? 

message: Kepler is the first scientist who determined that human sight results from image projected onto the retina. So should we add it into the article? KyleRGiggs 09:21, 12 July 2007 (UTC)
thread_title:  Retina 

message: I think the Holy Roman Empire part of "Regensburg, Bavaria, Holy Roman Empire" (where Kepler died) is inappropriate.  As Peter Hamish Wilson remarks (in The Holy Roman Empire, 1495-1806, Palgrave Macmillan, 1999) "many scholars dispute whether [the Holy Roman Empire] was indeed a state at all."  Besides, the article adds only a simple "Germany" to "Stuttgart."  I propose to change Kepler's place of death to "Regensburg, Germany" - second choice: "Regensburg, Bavaria, Germany." Iterator12n  Talk  04:12, 15 July 2007 (UTC)
thread_title:  Holy Roman Empire 

message: The first line reads: Johannes Kepler was a German Lutheran mathematician, astronomer and astrologer, and a key figure in the 17th century astronomical revolution.
I don't see that his religious affiliation should be given such prominence.  If it is important to his work, or his outlook, or his personality, then it should be referred to elsewhere and explained there.  However, to define him by his religion seems bizarre.  Would we say "JFK was an American Catholic politician", "Carl Sagan was an American atheist astronomer", "Katherine the Great was a Russian Orthodox ruler" etc?  Kitty Davis 08:12, 15 July 2007 (UTC)
replies: text: I noticed that on the front page and was going to remove it for precisely the reasons you cite, but somebody beat me to it.  •Jim62sch• 11:48, 15 July 2007 (UTC)
replies: text:  His opinions on religion and his troubles with Lutheran orthodoxy are mostly absent in the article. Also the background of Counter-Reformation shaping his stays at Graz and Linz is barely mentioned. --Pjacobi 17:07, 15 July 2007 (UTC)
thread_title:  Lutheran 

message: Good article. I was hoping to find some mention of to Kepler's contributions early ideas of the calculus - in particular Stereometrica doliorum ("Volume-measurement of Barrels"). Just a thought if anyone wants to add new material. Rob Burbidge 13:43, 18 July 2007 (UTC)
thread_title:  Stereometrica doliorum and contributions to mathematics 

message: Only a brief mention is made concerning one of Kepler's most important scientific ideas. This was the magnetic theory of planetary orbits. He was the first to hypothesise some kind of motive force that caused the revolution of the planets. This is only briefly mentioned. It is the foundational idea for the later theory of gravity invented by Newton. It is an important forward step. Yet its importance is neglected. I realise that in this article, Kepler's scientific work is not the main focus. However, at the very least, I would like to see the following included as one of the external links so that this important aspect of Kepler's work will not be further neglected. 
— Preceding unsigned comment added by 72.64.37.102 (talk) 16:27, 19 July 2007 (UTC)
thread_title:  Kepler's Magnetic Astronomical Theory 

message: http://www.xkcd.org/21/
Does Johannes Kepler have anything to do with this joke?
67.53.145.48 14:24, 1 September 2007 (UTC)
thread_title:  xkcd Bookstore Joke 

message: The article is currently in flagrant contradiction between its following two conflicting claims in two different passages as italicised and capitalised here: 
'Work for Tycho Brahe' section
"Two days after Tycho's unexpected death on October 24, 1601, Kepler was appointed his successor as imperial mathematician; he INHERITED Tycho's observations as well as the responsibility to complete his unfinished work."
'Astronomia nova' section
"By the end of the year, he completed the manuscript for Astronomia nova, though it would not be published until 1609 due to legal disputes over the use of Tycho's observations, the PROPERTY OF HIS HEIRS."
Also
"In 1623, Kepler at last completed the Rudolphine Tables, which at the time was considered his major work. However, due to the publishing requirements of the emperor and negotiations with Tycho Brahe's HEIR, it would not be printed until 1627."
I provisionally propose the following replacement from the word Kepler:
'...Kepler was appointed his successor as imperial mathematician with the responsibility to complete his unfinished work. He illegally appropriated [some of] Tycho's observations, the property of his heirs, which subsequently led to 4 year delays each to the publications of two of his works whilst he negotiated copyright permissions.'
However, it is unclear from the literature (i) what exactly this formal responsibility, if any, consisted of, and whether or not it was fulfilled more faithfully by Longomontanus in his 1622 Astronomia Danae and (ii) whether Kepler appropriated and secreted all of Tycho's observations, or only some of them, such as those for Mars especially. 
The question of what happened to Tycho's observations and who had access to them in the 17th century, and especially Longomontanus, is crucial to determining the issue of such as whether Kepler's proposed three ellipse laws were confirmed or refuted by them. 
--Logicus (talk) 15:46, 24 February 2008 (UTC)
thread_title:  Kepler did not inherit Tycho's observations, but misappropriated them 

message: The word "polygons" in a box in the main article seems to be a mistake for "polyhedra" or "polyhedrons".  —Preceding unsigned comment added by 81.135.224.70 (talk) 15:18, 14 July 2008 (UTC)
replies: text: thanks i'll change to perfect solids per image description page, tpbradbury (talk) 21:43, 23 November 2008 (UTC)
thread_title:  Mistake 

message: Another thing named after Johannes Kepler is the Kepler Track.
http://en.wikipedia.org/wiki/Kepler_Track
58.3.78.89 (talk) 10:27, 21 December 2008 (UTC)
thread_title:  Named after 

message: The way Kepler came across the three laws is mentioned in http://www.wlym.com/~animations/
part4/47/index.html  —Preceding unsigned comment added by 87.194.34.71 (talk) 10:32, 28 April 2009 (UTC)
thread_title:  Greater detail 

message: There should be a Wikipedia article on Kepler's Epitome. It is free from the 
tedious matter in his other books.  —Preceding unsigned comment added by 86.137.170.8 (talk) 10:13, 21 May 2009 (UTC)
thread_title:  Epitome 

message: All the learned contributors to this article are invited to the fact that Kepler had written his
own epitaph  :
                       Skybound was the mind, I measured the skies
                       the earthbound body, the body rests   now.
2.It is very intresting and heart moving point in the life of the scientific giant who was very modest, not known to show any attitude in his life marred with struggle, poverty and controvery. So if he ever claimed any prowess of his capabilities even in the shape of an epitaph, it is our duty to pay tribute to him by recording the modest couplet in the light of the fact that Kepler indeed measured the skies.The couplet in itself is a poetic marvel.It is left to the makers of the articles as to where this couplet should be incorporated in the main articles. But incorporated it should be for it is too beautiful to be wasted.And our Wikipedia can't leave out such facts.
Regards
SubzbhartiSubzbharti (talk) 09:35, 17 June 2009 (UTC)
thread_title:  Epitaph 

message: I have found some more information on the epitaph which is from the book, 100 GREAT SCIENTISTS, American Library,in the biography of Kepler. The exact lines of the couplet are as under as per this book:
 measured the skies, now the shadows I measure,
Sky-bound was the mind, earth-bound the body rests.'''
subzbharti  22 Dec 2009
All the learned contributors to this article are invited to the fact that Kepler had written his
own epitaph  :
                       Skybound was the mind, I measured the skies
                       the earthbound body, the body rests   now.
2.It is very intresting and heart moving point in the life of the scientific giant who was very modest, not known to show any attitude in his life marred with struggle, poverty and controvery. So if he ever claimed any prowess of his capabilities even in the shape of an epitaph, it is our duty to pay tribute to him by recording the modest couplet in the light of the fact that Kepler indeed measured the skies.The couplet in itself is a poetic marvel.It is left to the makers of the articles as to where this couplet should be incorporated in the main article. But incorporated it should be for it is too beautiful to be wasted.And our Wikipedia can't leave out such facts.
Regards
SubzbhartiSubzbharti (talk) 09:36, 17 June 2009 (UTC)
thread_title:  Epitaph 

message: The word "legitimize" appears in the second paragraph. I am not sure how exactly the 
legitimising took place. Any activity of Kepler's in this respect was hardly
unique to Kepler. Many others made much the same remarks about Galileo's observations.  —Preceding unsigned comment added by 86.180.182.155 (talk) 12:37, 2 December 2009 (UTC)
thread_title:  Vague 

message: It is not stated clearly in the article whether Kepler's mother was actually tortured or not.  —Preceding unsigned comment added by 86.180.182.155 (talk) 12:29, 3 December 2009 (UTC)
thread_title:  Not clear 

message: With these edits I have removed two external links: astromedia.de because nothing on Kepler was there; and sacred-texts.com because that link is already at Harmonices Mundi which it covers.
The other links are probably suitable, but they need better organising and descriptions. One puzzles me: calderon-online.com is a flash website that attempts to show (I think) using sound and animation musical interpretations of various orbital properties, but I wonder if it makes much sense to a reader.
* Calderón Urreiztieta, Carlos. Harmonice Mundi • Animated and multimedia version of Book V
-84user (talk) 21:08, 15 February 2010 (UTC)
replies: text: I find Calderón's representation of Kepler's Harmonices Mundi to be excellent.  Kepler's text is obscure, and Calderon's presentation of Kepler's text with music and animation is a revelation.  It's just the kind of illustration that belongs in an encyclopedia; I'd keep it.  --SteveMcCluskey (talk) 21:59, 15 February 2010 (UTC)
thread_title:  External links 

message: Substituted at 20:36, 3 May 2016 (UTC)
thread_title: Assessment comment