Investigations of the interstellar medium at Washburn Observatory, 1930-58

Between 1930 and 1958, the Washburn Observatory of the University of Wisconsin-Madison was home to pioneering photometric research into the interstellar medium by Joel Stebbins and Albert Whitford. Between 1933 and 1941, Stebbins and Whitford published seminal research on the photometry of stellar reddening, using the Washburn 15-inch refractor and the 60- and 100-inch reflectors at Mount Wilson Observatory. Many factors were responsible for the Washburn Observatory's pre-eminence in this area. This paper reviews their research on interstellar dust during the years 1922-58, the observational technology and scientific methods that were developed at the Washburn Observatory during that time and the scientific discoveries that originated there. We discuss the factors that enabled Washburn Observatory to become a leader in photometry during the first half of the twentieth century. We also draw on the recollections of past and present Washburn Observatory scientists to understand how Washburn's standing led to a subsequent programme of research into the interstellar medium at the University of Wisconsin-Madison. The resulting portrayal of Washburn Observatory provides insights into the evolution of astronomical research in America, from the beginning of the twentieth century until today.