For thousands of years Saturn marked the edge of the known solar system, until a teenage military deserter who made his living playing the oboe doubled its size in a single night. This episode follows William Herschel from the Battle of Hastenbeck, where his father told him to flee, to Bath, England, where he became organist at the Octagon Chapel, composed symphonies, and fell into astronomy through Robert Smith’s books on harmonics and optics. It explains why glass lenses suffered from chromatic aberration, why Herschel ground speculum metal mirrors for up to 16 hours a day, and how eliminating the secondary mirror in his Herschelian design saved precious starlight.

The heart of the story is the partnership with his sister Caroline, who recorded his shouted observations by candlelight, discovered eight comets with her own sweeper telescope, and became the first woman in England paid as a professional scientist. The episode covers the March 13, 1781 discovery of Uranus, the failed attempt to name it after King George III, the royal pardon for desertion, the near-fatal foundry explosion while casting a 1,000-pound mirror for the 40-foot telescope, the cataloging of over 2,400 nebulae, and the 1800 prism experiment that revealed infrared radiation. It also explores his stranger ideas, including inhabited suns and a link between sunspots and wheat prices.

• How Anders Lexell’s orbital calculations proved the new object was a planet, not a comet
• Why the massive 40-foot telescope was a practical nightmare and the 20-foot did most of the work
• How decades of binary star tracking gave the first proof that Newton’s gravity works beyond the solar system
• The thermometer placed just past the red band that registered invisible heat
• How the Herschel catalogs became the backbone of the NGC numbers still used today