{"api_version": 1, "bodies": {"moon": {"label": "Moon", "kind": "moon", "mean_synodic_days": 29.530589, "maya_period_days": 29.530864197530864, "confidence": "attested"}, "mercury": {"label": "Mercury", "kind": "inferior", "mean_synodic_days": 115.8775, "maya_period_days": 116, "confidence": "debated"}, "venus": {"label": "Venus", "kind": "inferior", "mean_synodic_days": 583.92, "maya_period_days": 584, "confidence": "attested"}, "mars": {"label": "Mars", "kind": "superior", "mean_synodic_days": 779.94, "maya_period_days": 780, "confidence": "attested"}, "jupiter": {"label": "Jupiter", "kind": "superior", "mean_synodic_days": 398.88, "maya_period_days": 399, "confidence": "debated"}, "saturn": {"label": "Saturn", "kind": "superior", "mean_synodic_days": 378.09, "maya_period_days": 378, "confidence": "debated"}}, "rings_au": {"mercury": 0.387, "venus": 0.723, "earth": 1.0, "mars": 1.524, "jupiter": 5.203, "saturn": 9.537}, "ephemeris": "de440s.bsp", "body_notes": {"moon": {"title": "Moon: 405 lunations = 11,960 days", "summary": "The Maya lunar counts are well attested. The tool shows the lunation as 11,960 / 405 = 29.5309 days.", "points": ["The modern mean lunation is 29.530588 days, the value FAMSI uses for its lunar entries.", "The Dresden Codex eclipse table spans 405 lunations = 11,960 days = 46 × 260 = 5 × 2,392 (FAMSI, Chanier).", "Two lunar equations are named for the places that used them: Palenque, 81 lunations = 2,392 days (29.5309), and Copan, 149 lunations = 4,400 days (29.5302).", "The table moves in steps of 177 days (6 lunations) or 148 days (5 lunations). Chanier and a popular site report this; I did not find it in a scholarly primary source.", "The bar shows the moon's phase (0 = new moon) from the real Sun-Moon angle. The Lunar Series glyphs that count the moon's age on monuments were not checked here."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "mayan.org, Dresden Codex Astronomy (popular site, no named author)", "url": "https://mayan.org/myths/dresden-codex-astronomy/", "read": "full page, low confidence"}]}, "venus": {"title": "Venus: 584 days", "summary": "The 584-day Venus cycle is the best attested of the planetary periods.", "points": ["The modern mean synodic period is 583.92 days. FAMSI lists 584 (= 8 × 73) as the Venus synodic period, and Chanier reports codex evidence for Venus.", "FAMSI lists four intervals: 236 days as morning star, 90 invisible at superior conjunction, 250 as evening star and 8 invisible at inferior conjunction (they sum to 584). A popular site gives 263/50/263/8 instead, so the split is not settled here.", "Arithmetic: 5 × 584 = 8 × 365 = 2,920 days, and the 37,960-day “Venus Round” is 65 × 584 = 104 × 365 = 146 × 260.", "The tool counts days from inferior conjunction. Codex tables are usually described as starting at a heliacal rising, a few days later, so do not expect an exact match to a codex row (my note, not checked against the codex)."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "mayan.org, Dresden Codex Astronomy (popular site, no named author)", "url": "https://mayan.org/myths/dresden-codex-astronomy/", "read": "full page, low confidence"}]}, "mars": {"title": "Mars: 780 days", "summary": "The 780-day Mars cycle (3 × 260) is well attested as the Mars synodic period.", "points": ["The modern mean synodic period is 779.94 days. FAMSI lists 780 as the “Triple Sacred Almanac (Mars synodic period)”, equal to 3 × 260, and marks it as both astronomical and numerological.", "Chanier reports codex evidence for Mars. A popular site places the Mars table at Dresden Codex pages 43–45.", "Mars's orbit is noticeably elliptical, so the day shown (phase × 780) is only approximate.", "Claims that the table encodes Mars's retrograde loops were not verified here. The retrograde flag in the tool comes from the real sky, not from the Maya table."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "mayan.org, Dresden Codex Astronomy (popular site, no named author)", "url": "https://mayan.org/myths/dresden-codex-astronomy/", "read": "full page, low confidence"}]}, "mercury": {"title": "Mercury: 116 days (117 is the alternative)", "summary": "Support for the Maya tracking Mercury's synodic cycle is only tentative in the sources checked, and they differ on its length.", "points": ["The modern mean synodic period is 115.88 days. The tool uses 116, which the FAMSI table lists as the Mercury synodic period.", "FAMSI also lists 117 (= 9 × 13), a cycle associated with a rain god, only as “Mercury synodic period?”. Its legend says a question mark means only tentative support for use by the Maya.", "Chanier, a preprint, takes 116 as the Mercury period and says evidence for Mercury, Venus and Mars appears in the codices, citing other work that has not been checked here.", "Mercury stays close to the Sun and is hard to see, so a table for it is harder to confirm than one for Venus or Mars."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "Bricker & Bricker (2011), Astronomy in the Maya Codices, American Philosophical Society", "url": "https://www.degruyterbrill.com/document/doi/10.70249/9798893980257/html", "read": "not read"}]}, "jupiter": {"title": "Jupiter: 399 days", "summary": "The 399-day period is a tentative identification, and the evidence that the Maya tracked Jupiter is weaker than for Venus or Mars.", "points": ["The modern mean synodic period is 398.88 days. FAMSI lists 399 as the Jupiter synodic period but marks it “*?” (tentative).", "Linden & Bricker (2023) argue that over a 20 × 819-day calendar the synodic periods of all the visible planets line up with station points. Only the abstract was available here, so their evidence is unchecked. The arithmetic itself holds: 19 × 819 = 39 × 399.", "Chanier says references to Jupiter and Saturn appear in “some Maya texts”, in contrast to codex evidence for Mercury, Venus and Mars.", "Bricker & Bricker (2011) has an appendix on Jupiter and Saturn, known here only from its table of contents."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Linden & Bricker (2023), The Maya 819-Day Count and Planetary Astronomy, Ancient Mesoamerica 34(3)", "url": "https://doi.org/10.1017/S0956536122000323", "read": "abstract only, paywalled"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "Bricker & Bricker (2011), Astronomy in the Maya Codices, American Philosophical Society", "url": "https://www.degruyterbrill.com/document/doi/10.70249/9798893980257/html", "read": "not read"}]}, "saturn": {"title": "Saturn: 378 days", "summary": "The 378-day period is a tentative identification, and the evidence that the Maya tracked Saturn is weaker than for Venus or Mars.", "points": ["The modern mean synodic period is 378.09 days. FAMSI lists 378 as the Saturn synodic period but marks it “*?” (tentative).", "Linden & Bricker (2023) argue for a link through the 819-day count. Only the abstract was available here. The arithmetic holds: 6 × 819 = 13 × 378.", "Chanier says references to Jupiter and Saturn appear in “some Maya texts”, in contrast to codex evidence for Mercury, Venus and Mars.", "Bricker & Bricker (2011) has an appendix on Jupiter and Saturn, known here only from its table of contents."], "sources": [{"title": "Van Stone (2012), Numerical Factors and Periods Important in Maya Calendrics, FAMSI (after Carlson 1981)", "url": "https://www.famsi.org/research/vanstone/2012/NumericalFactors.html", "read": "full page"}, {"title": "Linden & Bricker (2023), The Maya 819-Day Count and Planetary Astronomy, Ancient Mesoamerica 34(3)", "url": "https://doi.org/10.1017/S0956536122000323", "read": "abstract only, paywalled"}, {"title": "Chanier, Solution of the Mayan Calendar Enigma, arXiv:1601.03132 (preprint by an independent researcher)", "url": "https://arxiv.org/abs/1601.03132", "read": "full text"}, {"title": "Bricker & Bricker (2011), Astronomy in the Maya Codices, American Philosophical Society", "url": "https://www.degruyterbrill.com/document/doi/10.70249/9798893980257/html", "read": "not read"}]}}, "correlations": {"gmt": 1137142, "thompson": 1137140, "spinden": 1232041, "hochleitner": 1142840}, "tzolkin_names": ["Imix", "Ik", "Akbal", "Kan", "Chicchan", "Cimi", "Manik", "Lamat", "Muluc", "Oc", "Chuen", "Eb", "Ben", "Ix", "Men", "Cib", "Caban", "Etznab", "Cauac", "Ahau"], "haab_months": ["Pop", "Uo", "Zip", "Zotz", "Tzec", "Xul", "Yaxkin", "Mol", "Chen", "Yax", "Zac", "Ceh", "Mac", "Kankin", "Muan", "Pax", "Kayab", "Cumku", "Uayeb"], "long_count_units": {"baktun": 144000, "katun": 7200, "tun": 360, "uinal": 20, "kin": 1}, "calendar_round_days": 18980}