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Edmond Halley (1656 - 1742)
Edmond Halley was an English astronomer, interested primarily in observations of the Moon, the movements of planets, and the laws of gravity. He studied at Queen's College in Oxford, and after graduating in 1676, moved to St. Helena to observe stars in the Southern Hemisphere. This may have been because he was bored of observing the stars visible from England, or because the weather is better in St. Helena (or even both!). After returning to England in 1678, he published Catalogus Stellarum Australium which roughly translates as Catalogue of Australian Stars (it was fashionable at the time to give astronomical books Latin names, even though nobody actually spoke the language!) which detailed the stars he had observed while down under.
Although contributing to many other scientific projects, Halley is most famous for predicting the return of Halley's Comet (of course, it wasn't called Halley's Comet at the time!). He looked at details of a comet that had been observed in 1682. He noticed that this comet shared characteristics with a comet that had appeared in 1531 and another in 1607. He realised that these three comets might actually be the same one, and that approximately every 75-76 years it reappeared. He predicted that the comet would reappear again in approximately 1757. Although he died fifteen years before then, Halley's theory proved correct, and his comet was observed again in 1758, slightly later than he predicted although this delay was due to gravitational influences of Jupiter and Saturn. The fact that Halley was able to predict when his comet would appear meant that scientists could look through older observational records and find out when else the comet had been spotted. They discovered that ancient records from Chinese astronomers from possibly as far back as 467 BC showed that an object that they had observed was in fact Halley's Comet, with many other observations of the same object in between then and now. Halley's Comet is next expected to be visible in 2061 or 2062. As well as his comet, craters on the Moon and Mars and a research station in Antarctica are named after Edmond Halley.