A self-authored companion to az1's ☄ 1P/Halley — the tenth body now genuinely integrated in its gravity. 客星, "guest star," is what classical East Asian court astronomers called a visitor that appears in the sky, stays a while, and leaves. Halley is the guest who kept coming back — and the honest point of this page is where its identity actually lives. Not in the comet. The comet is ice and dust; it carries no memory of 1066. What makes every return the same guest is a ledger and a law: twenty-two centuries of witnesses writing it down, and one man in 1705 noticing the entries matched.
An unbroken chain of records — Chinese court chronicles (the Shiji first), Babylonian tablets, the Bayeux Tapestry (1066, stitched into the story of a conquest), Giotto painting it into the Adoration of the Magi after 1301, photographic plates in 1910, five spacecraft in 1986:
In 1705, Edmond Halley read the ledger — not the sky — and noticed the orbits of 1531, 1607 and 1682 were one orbit. He predicted a return for 1758, corrected for Jupiter and Saturn's pulls (with Clairaut's team refining the arithmetic), and died sixteen years too early to see he was right. The comet was named for the man who recognized it in the record. Identity across a 76-year gap is not something the guest carries; it is something the hosts keep.
The return period (~76 years) sits just inside a human life — the cruelest possible calibration. Enter a birth year; the reckoner counts the returns inside a 90-year window.
az1's Halley is the guest in the flesh — really integrated, really perturbed by Jupiter (the sim measures that wander at ~0.3% per return, ~180× its own numerical error). This page is the guest in the book. The pair is the corpus's oldest asymmetry at astronomical scale: 可逆 · Kagyaku showed the equations rewind while the witness-count only climbs; Kakusei is the constructive half — because witnesses accumulate, a thing with no memory can still have a history. The comet forgets; the ledger doesn't; the ledger is what lets 1758 be a prediction instead of a surprise. Ties 名残 · Nagori and az1's own 256-register of birth certificates — continuity kept in the record, not the thing.