Sir Robert Stawell Ball was an Irish astronomer. He worked for Lord Rosse from 1865 to 1867. In 1867 he became Professor of Applied Mathematics at the Royal College of Science in Dublin. In 1874 Ball was appointed Royal Astronomer of Ireland and Andrews Professor of Astronomy in the University of Dublin at Dunsink Observatory. In 1892 he was appointed Lowndean Professor of Astronomy and Geometry at Cambridge University. His lectures, articles and books (eg. Starland and The Story of the Heavens) were mostly popular and simple in style. However, he also published books on mathematical astronomy such as A Treatise on Spherical Astronomy. His main interest was mathematics and he devoted much of his spare time to his "Screw theory". He served for a time as President of the Quaternion Society. His work The Story of the Heavens is mentioned in the "Ithaca" chapter of James Joyce's Ulysses.