Edmond (or Edmund) Halley, FRS (8 November 1656 – 14 January 1742) was an English astronomer, geophysicist, mathematician, meteorologist, and physicist. He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720. From an observatory he constructed on Saint Helena in 1676–77, Halley cataloged the southern celestial hemisphere and recorded a transit of Mercury across the Sun. He realized that a similar transit of Venus could be used to determine the distances between Earth, Venus, and the Sun. Upon his return to England, he was made a Fellow of the Royal Society, and with the help of King Charles II, was granted a master's degree from Oxford.
