Herschel, << HUR shuhl, >> Sir William (1738-1822), was a British astronomer who founded stellar astronomy, the study of the region beyond the solar system. He was the first astronomer to observe that many indistinct objects in the heavens are star systems similar to the Milky Way. Herschel discovered over 2,500 such objects and more than 800 double stars. He used telescopes he built. The mirror of one of these had a diameter of 4 feet (1.2 meters). It was the largest telescope until 1845.
In 1781, Herschel discovered the planet Uranus. He later found two satellites of Uranus and two satellites of Saturn. His other achievements include pioneering studies of the sun’s motion through space, of the relative brightness of stars, and of infrared rays.
Herschel was born on Nov. 15, 1738, in Hanover, Germany. He settled in England in 1757. He died on Aug. 25, 1822. His sister Caroline and his son, John, were also astronomers.
