Orion as Calibration Origin: Southern Anchor of the Obliquity Framework and Vernal Equinox Gate of the Vedic Calibration Epoch

Orion as Calibration Origin: Southern Anchor of the Obliquity Framework and Vernal Equinox Gate of the Vedic Calibration Epoch
Research Notes 1–3 of this series identified the northern obliquity structure of the Vedic astronomical system: Vega as topological attractor, Thuban and Polaris as near-tangent precession cone markers, and sin²(obliquity) = 0.1582 as the master CP coupling constant. We now show that Orion completes this framework as its southern anchor. The three belt stars (Mintaka, Alnilam, Alnitak) sit at ecliptic latitudes of −23.55°, −24.51°, and −25.29° — bracketing Earth's obliquity (23.44°) from below. Mintaka sits within 0.11° of the exact obliquity threshold, the same precision as Thuban's northern cone proximity (0.20°). Six of Orion's nine principal stars occupy Mrigashira (lord: Mars); Rigel alone — the constellation's brightest star and deepest ecliptic point (−31.12°) — falls in Rohini, the Moon's exaltation nakshatra, establishing a Moon axis from Vega (northern correction node, Abhijit) to Rigel (southern lunar anchor) spanning the full bilateral obliquity geometry. Precession calculation places the vernal equinox at Orion's belt centroid at approximately 3,986 BCE, within the Rigvedic composition window, confirming Orion as the Year's Gate at the moment of the tradition's encoding. The complete framework is a four-point obliquity compass — Vega (north attractor), Orion's belt (south marker), ecliptic (mirror plane), obliquity (the single governing distance) — calibrated at two epochs separated by 10,000 years and encoded in a single coherent astronomical tradition.