NHAS - Today in Astronomy History

	375	Chinese astronomers observe and record an occultation of Mars by Venus.
	1742	British scientist and astronomer Edmond Halley dies. He was instrumental in getting Issac Newton's Pricipia Mathematica published, having paid the printing costs out of his own pocket. He created a world map depicting prevailing wind directions - believed to be the world's first meteorological chart, and conducted a study of mortality rates as they related to age, eventually leading to the first actuarial tables for life insurance. Halley's work on the orbits of comets lead him to believe that the comet of 1682 was periodic and was the same object as the comet of 1531, and 1607. He further speculated that this same comet had appeared in 1305, 1380, and 1456. Having established a period of 76 years, he predicted it would reappear in 1758. The reappearance of Halley's Comet on Christmas Day, 1758 secured him everlasting fame, although he did not see it, having died 15 years earlier.