William Herschel

William Herschel (1738-1822) was the first astronomer to systematically look beyond the solar system into the depths of intergalactic space. His early sky survey formed the foundation of today’s NGC (New General Catalog) of deep sky objects.

Born into a musical family in Hanover, Germany, Herschel mastered the oboe and made his living as a professional musician. He played in the Hanoverian Guard during the Seven Year War, but abandoned his military career and fled to England.

Herschel was blessed with a winning personality, so he made many friends in England and secured a lifetime appointment as an organist in Bath. He continued to compose, and he was pretty good at it… you can listen to a sample of his work here.  Yet he was bored, and turned for challenge to astronomy, starting with the popular works of James Ferguson. Herschel was captivated by the mysterious “nebulae”, the distant “cloudy stars”. But he was frustrated by the crude aberration-ridden refractors of the day and was the first to build and use large aperture Newtonian reflectors to see deeper into space.

He built more than 400 telescopes. In his most ambitious attempt, he tried to make a 36” metal mirror using a cast of hardened horse dung. The cast leaked molten metal onto the floor of his workshop, causing flagstones to explode and ricochet off the ceiling. This episode aside, Herschel made some of the finest large-aperture telescopes in the world at that time and earned income by selling them to kings and wealthy individuals throughout Europe.

A replica of the telescope with which William Herschel discovered the planet Uranus.

But Herschel was more than a mechanic. He became a supremely patient and skilled observer. His detailed knowledge of the stars enabled him to discover an unexpected celestial wanderer: the planet Uranus. This discovery, made in 1781 with a 6” reflector, gained him fame and freedom: he was granted fellowship in the Royal Society and a rich stipend from King George III.

With his hand-made reflectors, and with the help of his sister and assistant Caroline, he was the first to discover that many nebulae were made of stars (these were the globular and tight open clusters). But he also concluded some nebulae (planetary nebulae, for example) were made of a “shining fluid” of unknown constitution, which remained unknown until the 19th century.

Herschel assumed we lived in a vast cluster of stars and set out to map it by counting stars in different directions. He correctly concluded we lived in a flat disk of stars… a galaxy. He made many more conjectures of astonishing accuracy. He believed the Orion Nebula was “the chaotic material of future suns”. And he believed the Andromeda “nebula” was an island of millions of stars. He had no way of proving these conjectures, yet he was correct.

Despite his wealth, fame, and accomplishments, Herschel never lost his love “for this magnificent collection of stars” in which we live. He observed almost until his demise. May we all find a calling we enjoy as much.