The Angkor Wat equinox is a solar phenomenon considered as a hierophany that happens twice a year with spring and autumn equinox, as part of the many astronomical alignments indicative of a "fairly elaborate system of astronomy"[1] and of the Hindu influence in the construction of the vast temple complex of Angkor Wat, in Cambodia.

[3] In fact, it would be more correct to describe the phenomenon as the exact match of the shadow formed by the sunrise on Angkor Wat's central prang and the western entrance bridge.

[4] Angkor Wat was built by Suryvarman II, literally the Sun-King, during his reign for 1113 to 1150 with "astronomical and cosmic rhythm".

The temples' calibrated use of equinox sunrises to highlight the central tower and the bas-relief of the churning of the ocean of milk would have served as an eternal reminder of this king's "ringing in a new golden age.

[11] Accordingly, the gigantic representation of the churning of the sea actually works as a calendar: it positions the two solstice days at the extreme north and south, counts the days between them, and measures 54 units for the north- and southbound arcs of the sun and moon, emulating the symbolism on the bridge or in the western entrances, which repeat the 54/54-unit pairs several times.