Astrological beliefs were part and parcel of the science of astronomy in those days, and Zhang Heng was naturally an astrologer, but unlike those of today, notes Professor Huang bluntly, "All ancient astrologers were expert observers of the heavens. Today's astrologers don't know anything about the stars."
由於天文官擔負著天人感應任務，張衡更是「占星家」，「只不過古代占星家都是專業觀星人，今天占星家卻普遍不懂星星，」黃一農不諱言古、今占星家的大不同。