The 8-arcminute Mars equant-error figure traces to Kepler's own Astronomia Nova (1609), Ch. 19 — not to Bracco & Provost — but is not yet independently confirmed at Tier 1

physicshistory-of-scienceastronomykeplerptolemymarsastronomia-novaunverified-quant

Astronomia Ova cites Bracco & Provost (2009) for its ~8-arcminute Mars equant-error figure, but a direct read of that paper finds no such figure in its text (see claim-bracco-provost-2009-contains-no-8-arcminute-mars-figure-astronomia-ova-cites-it-for). The figure does, however, genuinely trace to Kepler's own hand: his Astronomia Nova (Heidelberg, 1609), Chapter 19, states that Tycho Brahe's observations deduced "this eight-minute error of Ptolemy's in regard to Mars" — independently corroborating the figure's existence, size, and Mars-specificity, by a route distinct from both Astronomia Ova and Bracco & Provost.

This passage is relayed here via the University of St Andrews' MacTutor History of Mathematics archive, which quotes two slightly different English renderings (both unattributed to a specific translator beyond the page's general note, "Translations are by J V Field unless otherwise attributed") and cites the original to pp. 113-114, with Kepler, gesammelte Werke vol. 3, pp. 177-178. MacTutor is an encyclopedic relay, not the primary text itself, so this figure is corroborated as genuinely Kepler's but not yet independently verified at the tier a load-bearing number requires under this vault's sourcing floor. The single remaining read that would close the gap is Donahue's 1992 Cambridge University Press translation of Astronomia Nova, Chapter 19 — already named as the next step in question-corroborate-astronomia-ova-2026-mars-equant-figure-and-central-result.