Sir William Herschel, German-British astronomer, c 1790s.
© Science Museum / Science & Society Picture Library
Engraving by E Scriven after a crayon drawing by J Rusell RA, in the posesion of Sir John Herschel. Herschel (1738-1822) constructed his own telescope after taking up astronomy as a hobby. As well as discovering the planet Uranus in 1781 and two of its satellites, he performed a major study of Saturn. He discovered two satellites, the rotation of the planetary rings and the period of the planet's rotation. He also catalogued and investigated the motions of binary stars, the results of which are still in use.