George Parker, 2nd Earl of Macclesfield (c.1695–1764), celebrated as an astronomer, spent much time conducting astronomical observations at Shirburn Castle, which his father had bought in 1716. Here he built an observatory and a chemical laboratory. The observatory was "equipped with the finest existing instruments" and the 2nd Earl of Macclesfield used it from 1740. In 1761 the astronomer Thomas Hornsby observed the transit of Venus from the castle grounds.