Andean Pleiades Forecast (Qullqa) (安第斯昴星預測)

THE ANDEAN PLEIADES FORECAST (Qullqa, ‘the granary’) — the indigenous weather forecast that SCIENCE VALIDATED: for at least four centuries, Andean potato farmers have climbed ridgetops around San Juan (24 June) to watch the pre-dawn rising of the Pleiades — bright and clear means timely rains and planting on schedule; dim or small means late, poor rains and planting postponed. Orlove, Chiang & Cane (NATURE 403, 2000) showed why it works: in El Niño years, high sub-visible CIRRUS dims the June Pleiades — and El Niño is what suppresses the October–December rains: the farmers were reading ENSO off the sky centuries before oceanography. THE HELIACAL WINDOW proven from the sky at load with the catalogue’s FIRST live star-rise computation (DefineStar, Alcyone): at Cusco the cluster rises AFTER the sun in late May (invisible, asserted) and leads it by over two hours on San Juan (asserted, monotonic widening between) — the tradition observes at exactly the moment observation becomes possible: THE DATE IS THE ASTRONOMY. The engine computes the window and serves the validated mechanism; it does NOT mint forecasts — the reading belongs to the farmers. Matariki, Camsa and Hesiod named as the cluster’s wider family. Andean becomes two. Pure compute and served science, no LLM.

Cost: 1 TIAN Points per call. tRPC procedure pleiadesForecast.window.