It seems clear from many sources that time, in the form of astronomy and calendars, is at the heart of feng shui.
In Yaodian, the cardinal directions are determined by the marker-stars of the mega-constellations known as the Four Celestial Animals.
- East: the Bluegreen Dragon (Spring equinox) --- Niao (Bird), α Hydrae
- South: the Red Bird (Summer solstice) --- Huo (Fire), α Scorpionis
- West: the White Tiger (Autumn equinox) --- Xu (Emptiness, Void), α Aquarii, β Aquarii
- North: the Dark (Mysterious) Turtle (Winter solstice) --- Mao (Hair), η Tauri (the Pleiades)
- Deborah Lynn Porter. From Deluge to Discourse. 1996:35-38
- Sun and Kistemaker. The Chinese Sky During the Han. 1997:15-18
- Aihe Wang. Cosmology and Political Structure in Early China. 2000:107-128
- Sarah M. Nelson, Rachel A. Matson, Rachel M. Roberts, Chris Rock, and Robert E. Stencel. Archaeoastronomical Evidence for Wuism at the Hongshan Site of Niuheliang. 2006