William Herschel – Biography
William Herschel was a German astronomer who discovered Uranus and other celestial objects, and he is the father of the astronomer John Herschel. Born in Hannover, Germany (November 15, 1738 – August 25, 1822).
Herschel began to calculate, design and build their own telescopes. Less than a year after having bought the Ferguson’s book, Herschel estimated and polished the most perfect and powerful mirrors around the world, because he understood immediately that the future depended on the reflecting telescopes.
He was building the instruments and observing the sky at the same time. As early as February 1774 he had already observed the Orion Nebula, discovered in 1610.
On March 13, 1781 Herschel noted an unregistered object at first glance, that looked like a comet: by studying this object carefully soon managed to determine that it was actually a new planet, Uranus.
Herschel had discovered the planet Uranus by testing his newly built reflecting telescope, of seven foot long, six inch diameter, ƒ14. He had pointed it to the constellation of Gemini and observed a star which was not supposed to be there. The object shone with a yellow color and moved slowly.
Herschel observed the object every night and came to the conclusion that he had discovered the seventh planet in the Solar System. He asked other astronomers to confirm the diagnosis, and all agreed with him: a new planet was located to twice the distance of Saturn.
In 1783, Herschel discovered that the Sun was not quiet as he had always believed. He showed that our Sun is moving and dragging the Solar System towards the star Lambda Herculis. He named the point where this movement is directed as “solar apex”. Four years later, on January 11, 1787, he discovered two moons of Uranus: Titania and Oberon.
In 1788, William Herschel married the widow Mary Baldwin Pitt, who had been married to the powerful London merchant John Pitt. Lady Pitt had lost her first husband two years before she met Herschel. William Herschel and Mary had one child, John Herschel, born at Observatory House on March 7, 1792.
William spent two years building a large telescope, and finished in 1789, with an aperture of 1.2 m. So he pointed the telescope to the night sky for the first time on August 28 and discovered the sixth Moon of Saturn, Enceladus, in few minutes. On September 17 he descovered the seventh Moon, Mimas, which gives an idea of the outstanding optical quality of that enormous instrument. This telescope was the largest telescope in the world for over fifty years, to be defeated only by the “Leviathan” of Lord Rosse, who had a mirror of 1.98 m in diameter.
William Herschel also discovered planets, moons, comets and more than 2,500 galaxies and nebulae, and realized that the Sun takes us towards Hercules.
He studied the movement of stars, designed a very correct model of the Milky Way on the basis of their statistics of populations of stars in each sector of the sky, showed ideas about the nature of nebulae, and filed a primitive theory of “Island Universes” (galaxies) which had been advanced by the philosopher Immanuel Kant.
William Herschel died on August 25, 1822 at his home in Slough, at the advanced age of 84. As a curious fact should be noted that the planet discovered, Uranus takes 84 years to its orbital period, so Herschel was born and died when Uranus was in the same position.