Xing, the Star of the Vermilion Bird

Xing, the Star, is the twenty-fifth of the twenty-eight xiu and the fourth mansion of the southern palace, the Vermilion Bird, the central mansion of the summer quarter. Its name means star, identified with stars in Hydra, seen as the neck of the celestial bird. In the later astrological tradition its animal totem is the Horse. As one of the twenty-eight lunar mansions it marks a portion of the Moon's path. These are the conventions of the Chinese astronomical and calendrical tradition, in which the twenty-eight xiu divide the sky into four palaces of seven mansions, the Vermilion Bird of the south spanning the summer heavens; each mansion is measured from a determinative star that fixes its beginning along the celestial equator.

Xing at the centre of the summer quarter, read as the celestial bird's neck, sits among stars in Hydra that fall within the same general stretch the Vedic scheme divides between Magha and the two Phalguni nakshatras, and the determinative-star method used to fix Xing's own boundary meant Chinese astronomers regularly re-measured this and the neighbouring mansions against observation as precession slowly shifted the underlying stars relative to the solstitial and equinoctial points the calendar depended on.