William Radcliffe Birt (1804–1881) was an English amateur astronomer in the 19th century. His name is used for the Birt crater, a minor crater on the Moon. Birt worked extensively with John Herschel, carrying out a great deal of meteorogical research on atmospheric waves, from 1843 to 1850. A lot of his work is held in the Scientist's Collection at the American Philosophical Society.
Probably on Herschel’s recommendation, Birt became involved with the Kew Observatory in the later 1840s under the Directorship of Francis Ronalds. He analysed and published the latter’s detailed atmospheric electricity and meteorological observations. They also worked together on a new design of kite for making meteorological recordings in the upper air. Birt was formally appointed in late 1849 as Ronalds’ assistant but their relationship soured shortly afterwards and Birt was requested by the Kew Committee to leave in mid-1850.
The lunar crater Birt is named after him.