On March 31, 1781, William Herschel, a German musician and composer, looked through a homemade 7-foot-long telescope in his back garden in Bath, England and saw something odd. He thought it was a comet, but it didn't act quite like other comets. And when scientists of the time calculated the object's distance and motion, they declared that it was actually a planet, the first new planet to be discovered since ancient times.
Herschel wasn't any amateur astronomer. He was a gifted telescope maker and observer of the skies, and he was well known to scientists of his time. Several of these scientists, including the president of the Royal Society, Sir Joseph Banks, urged Herschel to name his planet in honor of the king, George III, figuring that the king would have to honor Herschel in return and that this might allow Herschel to leave music and pursue astronomy full time.
The strategem worked. Herschel named the planet Georgium Sidus (the Georgian Planet) and, after much negotiations and an audition, the king hired Herschel as his personal astronomer at Windsor. The pay wasn't great—only £200, less than he earned as a musician and conductor in Bath—but his only duty was to entertain the royal family when requested, leaving plenty of time for observing the skies.
Herschel would continue making discoveries, including two moons of Saturn, two moons of his Georgian Planet and infrared radiation. He also coined the word "asteroid." It should also be noted that he had a most excellent assistant, his sister Caroline, who was a gifted astronomer in her own right (but a subject for another day).
The name Georgium Sidus didn't stick, though. Other, non-English astronomers of the time argued that the name just didn't fit the pattern. The other five known planets—Mercury, Venus, Mars, Saturn and Jupiter—were all named after gods and goddesses of classical times. Eventually the planet was named Uranus, the father of Cronus (Saturn) and grandfather of Zeus (Jupiter), though the name didn't come into use until after Herschel was dead.
The garden where Herschel discovered his planet and the home to which it is attached are now the Herschel Museum of Astronomy.