Edmond Halley

Edmond Halley was an English astronomer, geophysicist, mathematician, meteorologist, and physicist. From an observatory he constructed on Saint Helena in 1676–77, Halley catalogued the southern celestial hemisphere and recorded a transit of Mercury across the Sun. He realised that a similar transit of Venus could be used to determine the distances between Earth, Venus, and the Sun. Halley encouraged and helped fund the publication of Isaac Newton's influential Philosophiæ Naturalis Principia Mathematica (1687).