Jupiter and Saturn are splendid planets. With their associated rings and satellites, they excite the admiration of all observers. One perceptive writer compared the giant planets to French impressionist paintings. “Jupiter's orange and yellow bands are so roiled up that its disk might have been painted by van Gogh at Arles. Saturn, with more delicate bands of ochre, resembles a Monet haystack in a sunlit mist. Uranus' disk, though, is so featureless and limpid as to suggest the still pond around a Monet water lily” [1].

Saturn, recorded from the seventh century BC by the Babylonian astronomers, was the outermost planet known to the ancients. Uranus was the first planet to be discovered since antiquity. Its discovery by William Herschel (1738–1822) in 1781, although often called accidental, resulted from his careful checking of star positions and so was inevitable. He called it George's Star (Georgium Sidus) after King George III, who presented Herschel with a lifetime pension. Such nationalistic fervor did not receive universal acclaim and the planet was soon given the classical name of Uranus. Next it was discovered that the orbit of Uranus was being affected by another large body further away from the Sun. Study of these variations in the orbit of Uranus led eventually to the discovery, in 1846, of another large planet, Neptune.