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Thanks for raising this — what part of the intro was inaccurate? This was the source we used for the Kepler info: https://www.jstor.org/stable/27838992?seq=1#pa

• abecedarius 8y ago
  > Kepler first formulated his hypothesis: planets had elliptical orbits with two foci, and then set out to prove it mathematically. He didn't start with that hypothesis, he came to it after multiple tries at fitting other models like an equant (an offset circle with angular speed controlled from the opposite offset, which is actually a good first-order approximation to the Kepler-law motion at small eccentricity). > Only after repeating his procedures 70 times did he offset his computational errors. With a little less patience, he wouldn’t have proved his theory, and elliptical orbits would have eluded us for longer. I skimmed the paper, and it seems to be about Kepler fitting an equant instead of an ellipse. Apparently he used an iterative method, stopping after 70 iterations? And his numerical errors seem to be responsible for it not converging faster. That makes more sense to me than my misunderstanding that you were saying he ran through the whole calculation from the start 70 times. I jumped to a conclusion about that part, and I'm sorry. Julian Barbour's The Discovery of Dynamics explains what Kepler did in detail (it's not the whole topic of the book, but a big chunk of it). A great book -- I didn't really appreciate Kepler before reading it. Both brilliant and very human.