instruments / chronology / cyclic/README-before-the-objection.md · raw

The Lu section as committed before the objection (f166f57, 2026-09-08 13:26). A research program Kieran shapes and a model (the "seat") writes down. "I" in these files is the seat unless a line is quoted as his. The first write-up explained the misses instead of counting them; Kieran's objection ("this is cyclic") is in the file, and so is the retraction. Snapshot of 2026-10-15 from the private repo; local addresses and paths scrubbed, nothing else changed.

topics/chronology — line them up

Kieran, 2026-09-08: "if you're talking about cycles of Halley's comet or eclipses... line them up. for real. there's def no unbroken world history lineage from first principles."

First test: the Spring and Autumn Annals against the computed sky

Record. The 春秋 jing text as transmitted on zh.wikisource (12 dukes, fetched 2026-09-08, sources/wikisource/, revision ids in the manifest). 37 entries say 日有食之 ("the sun was eaten"); 31 carry a sixty-day cycle day; reign-years total 242 by the text's own count. Parsed by pipeline/ (see derived/chunqiu_eclipses.json). Nothing taken from a concordance: no BCE year, no month table, no cycle anchor.

Sky. Solar eclipses from orbital mechanics (astronomy-engine, VSOP87/ELP), no calendar assumed; restricted to eclipses visible at Qufu (35.6 N 117.0 E), the capital of Lu, on the local date.

Search. Two free parameters, exhaustively: the astronomical year of Duke Yin's first year (−1000 to −442) and the phase of the sixty-day cycle (60). A record matches a cell when an eclipse visible at Lu falls in that reign-year, within a month of the stated Zhou month (Zhou month 1 ≈ December/January), on a day whose cycle name is the one stated.

Result (pipeline/align.py --local --slack 0, derived/align_chunqiu_local.json):

first year of Duke Yin	matches of 31	note
−721 (722 BCE)	21	the conventional date; rank 1 of 33,540 cells; z ≈ 53
−667 (668 BCE)	15	54 years later: the exeligmos (three saros) alias
−775 (776 BCE)	14	54 years earlier: same alias
everything else	≤ 11	null mean 0.05

The ten misses at −721: seven have no eclipse visible at Lu in the window (either an error in the annal, an eclipse reported from elsewhere, or the visibility model's ΔT at the horizon); three are cycle-day mismatches, two of them the known duplicate entries where the annal records eclipses in consecutive months (襄公 21 months 9 and 10; 襄公 24 months 7 and 8), which the sky cannot do. Nobody was assumed error-free; the errors are the minority and the alignment holds without them.

The cycle phase at the peak is 49, which implies, if the sixty-day count has run unbroken, that 1 January 2000 was a 戊午 day. Any Chinese almanac can confirm or refute that; if it confirms, the day count runs unbroken from Lu to now, from first principles.

Caveats, left visible. The local-visibility criterion depends on the model's Earth-rotation history (ΔT), which is itself partly fitted to ancient eclipse records; the year alignment does not depend on it (the 54-year aliases do not move with ΔT). With eclipses anywhere on Earth instead of visible ones, the test aliases badly (six first-years tie). The month mapping is approximate (Zhou intercalation). Cross-check against JPL DE422 pending (data/ephemeris/).

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