An amateur astronomer doubled the size of the known solar system
William Herschel was scanning the night sky with a homemade telescope in his garden in 1781 when he spotted an object that refused to stay a point of light. He first assumed it was a comet. It turned out to be a new planet — Uranus — the first ever found that wasn't known to ancient observers.
— William Herschel, Account of a Comet — Philosophical Transactions of the Royal Society, 1781