How an Amateur Astronomer Discovered Uranus

William Herschel discovered a new planet with a telescope of his own design—and an assist from his sister Caroline.
A stained-glass window at the Coats Observatory near Glasgow, Scotland, depicts William Herschel.
A stained-glass window at the Coats Observatory near Glasgow, Scotland, depicts William Herschel. / Lairich Rig, Wikimedia Commons // CC BY-SA 2.0

On March 13, 1781, William Herschel looked through his telescope and saw Uranus. It was a monumental discovery for the world of science, but that wasn’t the only reason it was impressive.

First, the telescopes of the time were extremely limited. Herschel’s homemade device was more or less a tube-shaped magnifying glass, especially when compared to today’s high-powered sky-scanning technology.

Second, Herschel was a relative newcomer to astronomy. He’d spent most of his earlier life as a successful composer and musician, only developing an interest in the night sky at the age of 34. A few years later, Herschel was up one night, staring at the constellation Gemini, when he found a comet—or so he thought. The object in question looked more like a flat disk, and while it moved, it appeared to be too slow to be a comet. Further observations confirmed that Herschel had in fact found a new planet—the first to be discovered with a telescope.

As the discoverer, Herschel figured he had naming rights. He suggested Georgium Sidisliterally “George’s Star”—in honor of his patron, King George III, but his contemporaries argued for a more dignified and less nationalist name. They opted for Uranus, following the established protocol of naming planets after ancient gods.

In Greek mythology, Uranus is the primordial god of the sky and the son/husband of Gaea, the goddess of the Earth. Their many offspring included the Titans, dieties who overthrew their father and established Cronus, the youngest Titan, as the ruler of the world. Cronus (a.k.a. Saturn of Roman myth) was eventually overthrown by his son Zeus and his siblings, who became the Olympian gods. With that kind of provenance, “George’s Star” didn’t stand a chance.

William Herschel would go on to discover more than 2500 nebulae, coin the word asteroid, and invent several new telescopes. But he didn't do it alone: Supporting him in every scientific effort was his younger sister Caroline, who tirelessly polished his telescope mirrors, stayed up all night to record celestial observations, and edited and published his groundbreaking star catalogs. Her own list of achievements is extensive. Caroline Herschel described 14 new nebulae, assembled a catalog of star clusters, and discovered eight comets, among other firsts.

The Herschels’ discoveries paved the way for new technology and scientific approaches—and it all started with Uranus.

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A version of this story was published in 2016; it has been updated for 2024.