William Herschel
No one knows quite when William became interested in astronomy, but his sister Caroline’s memoirs recall him discussing the night sky with her on their journey to England. Shortly after their arrival, he began building his own telescopes – at first simply by assembling lenses obtained by local glassmakers, but later, as his needs grew more demanding, by casting mirrors and building reflecting telescopes of his own design.
Eventually, William had instruments that were fit for his plans – not just to observe the night sky, but to carry out detailed surveys in search of comets and other undiscovered objects. His telescopes were the best of their age, and his reputation soon began to spread. His first project involved a systematic catalogue of closely spaced stars, with William spending all his available nights at the eyepiece and Caroline making careful notes. At the time most people assumed that stars were randomly scattered through space, but the discovery of numerous close pairs convinced him otherwise. There were too many to be accounted for by chance alignments, so some of them at least must be paired binary stars in orbit around each other.
In March 1781, William spotted the planet now called Uranus. When he first saw the spherical bluish blob in the constellation of Taurus, he assumed it was a comet – it was Astronomer Royal Nevil Maskelyne who began to wonder whether the unusually solid-looking object might be a planet beyond Saturn. A few months later, continued tracking of the object’s movement confirmed that it was indeed a remote planet. Herschel suggested naming it George’s Star – after King George III – and the king returned the honour by naming William his personal astronomer and granting him a salary of £200 on condition that he moved to Windsor, with an additional £50 for Caroline to work as his assistant. The Herschels, both brother and sister, abandoned their musical careers to become some of Europe’s first professional scientists. They would go on to make countless other discoveries.
“His first project involved a systematic catalogue of closely spaced stars”