The story
Welcome to 19 New King Street. Take a moment to look up at this modest, honey-colored Georgian townhouse. To any passerby in the late eighteenth century, this was simply the comfortable home of a successful German-born musician named William Herschel.
But behind these limestone walls, a quiet revolution was brewing—one that would quite literally double the size of the known solar system. As you stand here, imagine the house as it was in the 1770s. William lived here with his sister, Caroline.
By day, the rooms echoed with the sound of music lessons and rehearsals; William was the organist at the Octagon Chapel nearby. But by night, the house turned into a laboratory. The basement was not used for laundry or storage, but for the messy, grueling business of telescope making.
William and Caroline would spend hours casting and polishing metal mirrors. It was dangerous, exhausting work. In fact, William was so dedicated to the polishing process that Caroline often had to feed him by hand so he wouldn’t have to stop and ruin the mirror's curve.
Now, follow the story through the house and out into the small, rectangular garden at the back. It is a humble space, typical of Bath’s terraced housing, but on the night of March 13, 1781, it became the most important spot on Earth. William had hauled his homemade seven-foot reflecting telescope out onto the paving stones.
He was conducting a systematic survey of the night sky when he noticed something unusual in the constellation of Gemini. It wasn't a point of light like a star; it had a distinct disk shape. Initially, Herschel thought he had discovered a comet.
But as he tracked its slow, steady orbit from this very garden, the truth became undeniable. He had found a seventh planet. It was the first planet to be discovered using a telescope, and the first discovery of its kind since antiquity.
In a move of brilliant political maneuvering, William decided to name his new find "Georgium Sidus," or "George’s Star," in honor of King George III. He hoped the gesture would win him royal favor, and it worked; the King appointed him "The King’s Astronomer," providing a pension that allowed William to quit his music jobs and focus entirely on the stars. While the name didn't stick outside of Britain—astronomers eventually settled on "Uranus" to keep with the tradition of mythological names—the legacy of that night at 19 New King Street remains.
Today, this house is a museum dedicated to the Herschels. As you explore, you are walking in the footsteps of a brother and sister who looked at a familiar sky and saw something no one else had ever seen. It serves as a lasting reminder that you don't need a mountaintop observatory to change history; sometimes, all you need is a homemade lens and a clear night in a Bath backyard.