Zenith Passage Alignments at Koh Ker

Koh Ker, a 10th-century Khmer city in Cambodia, features a unique architectural alignment to the zenith passage sunrise, unlike other Khmer temple complexes. The Prasat Thom complex is oriented 14 degrees north of east, with its western end, the Prang Pyramid, providing an unobstructed view to the horizon where the zenith passage sun rises. This alignment includes zenith passage tubes in roofs and linga statues acting as gnomons, designed to capture the exact moment of zenith passage at noon. A project documented this alignment from the top of the Prang Pyramid, providing evidence that Koh Ker's alignments are not anomalous by citing similar features in Java, Sri Lanka, and Angkor.

Barnhart, E. (2026). Zenith Passage Alignments at Koh Ker. Journal of Astronomy in Culture, 4(1). https://doi.org/10.5070/ac3.63828