Historians of science regard John Herschel (1792 - 1871) as one of the most influential British natural philosophers of the nineteenth century. He made important contributions in chemistry, optics, and the philosophy of science, but he was most widely regarded for his astronomical work. His investigations and publications on double stars, nebulae, variable stars, and constellation reform extended throughout his career and form an important chapter in sidereal astronomy prior to the advent of astrophysics. This dissertation is the first extensive survey of Herschel’s stellar astronomy, drawing upon his correspondence and unpublished diaries and manuscripts in addition to his scientific papers and texts. After a survey of historical ideas regarding the physical nature of the stars, the study examines Herschel’s relationship with nineteenth-century positional astronomy and argues that Herschel viewed star catalogues as a means of obtaining information on the physical nature of stars. By exploring Herschel’s contributions in double star and variable star research, this study illustrates how Herschel brought these fields of inquiry from the astronomical periphery, making them subjects of physico-mathematical research endeavors pursued by multiple observers. The work next contextualizes Herschel’s prismatic analysis, situating Herschel’s spectral investigations within his optical and photographical researches and offering an explanation of his ultimate response to spectroscopy. Finally, it concludes with a survey of Herschel’s influence on science writers throughout the nineteenth century to illustrate how his stellar conceptions were accepted and disseminated more broadly.
This treatment of Herschel’s stellar astronomy addresses broader questions in the history of nineteenth-century science. Firstly, it shows the evolution of conceptions regarding the stars in the decades leading up to spectroscopy. Drawing on assumptions common since the time of Copernicus, Herschel was instrumental in establishing and communicating many newly measured stellar properties. Secondly, this investigation complicates the division between amateur and professional astronomers during this period as Herschel attempted to recruit members of both observing communities for his projects. Herschel’s work marks the transition of sidereal astronomy from being the sole property of those with large telescopes as he advocated for programs in which even naked eye observers could make important contributions to understanding the stars.