Saturday, May 23, 2020

William Herschel the Man Who Discovered Uranus

Sir William Herschel was an accomplished astronomer who not only contributed volumes of work that astronomers use today, but also composed some pretty hip music for his time! He was a true do-it-yourselfer, building more than one telescope during his career. Herschel was fascinated with  double stars. These are stars in close orbits with each other, or that appear close to one another. Along the way, he also observed nebulae and star clusters. He eventually began publishing listings of all the objects he observed. One of Herschels most famous discoveries was the planet Uranus. He was so familiar with the sky that he could easily notice when something seemed out of place. He noticed that there was a dim something that seemed to move slowly across the sky. Many observations later, he determined it ws a planet.  His discovery was the first one of a planet that had been noted since ancient times.   For his work, Herschel was elected to the Royal Society and made Court Astronomer by King George III. That appointment brought him income he could use to continue his work and build new and better telescopes. It was a good gig for a skygazer of any age!   Early Life William Herschel was born on November 15, 1738 in  Germany and brought up as a musician. He began composing symphonies and other works as a student. As a young man, he worked as a church organist in England. Eventually his sister Caroline Herschel joined him. For a time, they lived in a house in Bath, England, which still stands today as a museum of astronomy.   Herschel met up with another musician who was also a math professor in Cambridge and astronomer. That sparked his curiosity about astronomy, which led to his first telescope. His observations of double stars led to studies of multiple star systems, including the motions and separations of the stars in such groupings. He catalogued his discoveries and continued to search the skies from his home in Bath. Ultimately he ended up re-observing many of his discoveries again to check their relative positions. In Over time, he managed to find more than 800 new objects in addition to observing already-known objects, all using a telescope he built. Ultimately, he published three major listings of astronomy objects:  Catalogue of One Thousand New Nebulae and Clusters of Stars  in 1786,  Catalogue of a Second Thousand New Nebulae and Clusters of Stars in 1789, and  Catalogue of 500 new Nebulae, Nebulous Stars, and Clusters of Stars  in 1802. His listings, which his sister also worked on with him, eventually became the basis for the New General Catalog (NGC) that astronomers still use today. Finding Uranus Herschels discovery of  the planet Uranus  was almost entirely a matter of luck. In 1781, as he was continuing his search for double stars, he noticed that one tiny point of light had moved. He also noticed that it wasnt quite star-like, but more disk-shaped. Today, we know that a disk-shaped point of light in the sky is almost certainly a planet. Herschel observed it a number of times to make sure of his finding. Orbital calculations pointed to the existence of an eighth planet, which Herschel named after King George the III (his patron).   It became known as the Georgian Star for a time. In France, it was called Herschel. Eventually the name Uranus was proposed, and thats what we have today.   Caroline Herschel: Williams Observing Partner Williams sister Caroline came to live with him after the death of their father in 1772, and he immediately had her join him in his astronomy pursuits. She worked with him to build telescopes, and eventually began doing her own observing. She discovered eight comets, as well as the galaxy M110, which is a smaller companion to the Andromeda Galaxy, and a number of nebulae. Eventually, her work caught the attention of the Royal Astronomical Society and she was honored by that group in 1828. After Herschels death in 1822, she continued to do her astronomical observations and expand his catalogues. In 1828, she was also given an award by the Royal Astronomical Society. Their  legacy of astronomy was carried on by Williams son, John Herschel.   Herschels Museum Legacy Herschel Museum of Astronomy in Bath, England, where he  lived part of his life, remains dedicated to preserving the memory of the work done by William and Caroline Herschel. It features his discoveries, including Mimas and Enceladus (circling Saturn), and two moons of Uranus: Titania and Oberon. The museum is open to visitors and tours.   There is a renaissance of interest in William Herschels music, and a recording of his most popular works is available. His astronomy legacy lives on in the catalogs that record his years of observations.

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