May 13, 2008

In Today's One Minute Astronomer...

William Herschel: World's First Deep-Sky Astronomer

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.

---- Highly Recommended ----

Discover the fascinating story of humanity's exploration of the universe... no math required! If you're interested in astronomy, this book is sure to appeal to you. Learn more...

-------------------------------

The Basics

• 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. He made many friends in England and secured a lifetime appointment as an organist in Bath. 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 aberration-ridden refractors of the day and learned to build 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 the time.

A Deeper Look

• 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 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.

• 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.

Good To Know

Herschel made many 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.

Personal View

Despite his wealth, fame, and accomplishments, Herschel never lost his love “for this magnificent collection of stars” in which we live. In the summer of 1819, at the age of 80, he wrote his sister to come dine with him and help him see a great long-tailed comet. May we all find a calling we enjoy as much.