Sirius, Standstill, and the Global Monument Record: A Systematic Survey of Dual Stellar-Lunar Encoding in Ancient Sacred Architecture

This revision supersedes the earlier revisions deposited under this record. All stellar quantities are recomputed at each site’s own construction epoch with a long-term precession model and the proper motion of Sirius; the identity is restated as a function of epoch; and the survey’s classifications follow from the recomputed values. Any figure of the earlier revisions that is not restated here is not maintained. The identity φ + |δ_Sirius| = ε + i, where ε is the obliquity and i the Moon’s inclination, selects a latitude at which the zenith distance of Sirius at culmination equals the Moon’s maximum standstill declination. Because Sirius has a large proper motion and its declination has been nearly stationary only for the last two millennia, the identity latitude is not a constant: it was undefined before the third millennium BCE, stood at 8° N in 2500 BCE, and has stood between 13° N and 11.9° N throughout the Common Era, passing 12.8° N in the twelfth century and 11.9° N today. The identity is therefore a property of the Common Era, and the Lalibela complex (12.03° N) sits on it: 0.75° from the identity latitude of its construction century and 0.16° from today’s. The survey of fifteen monuments is recomputed at epoch. Sirius orientation, assessed as the coincidence of a published axis with the star’s rising azimuth at the site’s epoch within 1.5°, is confirmed at Bete Giyorgis (0.0–0.7°) and Göbekli Tepe (0.2°), is marginal at Baalbek (3.8°), and is not supported at the Egyptian, Nubian, Sahelian, Mesoamerican and Andean sites, whose published axes lie 6° to 31° from the star’s rising at their epochs. Major-standstill encoding, taken from the published literature, is present at Stonehenge, Callanish and (provisionally) Arkaim above 51° N, at Nabta Playa at 22.5° N, and at no Egyptian or Levantine site; at Bete Giyorgis it is stated as a prediction for survey. The bimodal latitude distribution of standstill encoding, present at high latitude where the standstill Moon skims the horizon and absent through the Egyptian corpus where it culminates near the zenith, stands on the literature alone; Nabta Playa remains the intermediate-latitude anomaly, and its published “Sirius” line at 152° corresponds to a declination near −55°, which the star held in the tenth and sixteenth millennia BCE but not in the fifth. A reconciliation is added between standstill encoding and the obliquity readings of stone circles: a standstill declination is the obliquity plus a constant, so the two are one measurement in two vocabularies.