Zhāng Héng 張衡 (78–139) was the great Eastern-Hàn polymath — astronomer, mathematician, inventor of the seismoscope, court fù 賦 poet. Not to be confused with Zhāng Héng 張衡 (d. 179), the second Celestial Master, son of 張道陵 and father of Zhāng Lǔ 張魯. Daoist texts sometimes attribute hymns pseudepigraphically to “Zhāng Héng” — the intended figure is typically the Celestial Master son, though ambiguity persists (cf. KR5c0376 Tài shàng dòng shén wǔ xīng zàn).