Eustachio Manfredi (September 20, 1674 - February 15, 1739) was an Italian astronomer and mathematician. He attended Jesuit school, then studied at the University of Bologna, graduating with a degree in law in 1691. At the same time he devoted himself to scientific studies in mathematics and astronomy, and to literature. In 1698 Manfredi obtained the chair of mathematics at the University of Bologna. In 1707 he and Vittorio Francesco Stancari discovered the comet C/1707 W1. He wrote several works on astronomy. He demonstrated to church officials the heliocentric system (revolution of the Earth around the Sun), and as a result of this, the Church admitted the scientific natures of Galilean system and removed from the index many works of Galileo Galilei. In 1711 he became director of the Astronomical Observatory of Bologna, a position he held until his death. He died in 1739 at the age of 64.