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Session 27 - History and Teaching of Astronomy.
Oral session, Monday, June 10
Old Madison,

[27.01] James Craig Watson, First Director of Washburn Observatory: His Obsession with the Intra-Mercurial Planet Vulcan

W. Sheehan (Hutchinson, MN)

The first director of the Washburn Observatory, Watson began his career at the University of Michigan, where he discovered more than a score of asteroids and planned (but did not live to carry out) the first search for a trans-Neptunian planet. He became a strong supporter of Le Verrier's hypothesis that a planet closer to the Sun than Mercury (Vulcan) was causing the anomalous advance of 38" of arc per century of Mercury's perihelion, and mounted a special search for Vulcan at the July 29, 1878 total eclipse, at Separation, Wyoming, recording two strange reddish stars near the Sun which he assumed were intra-Mercurial bodies. With the exception of Lewis Swift at Denver, Colorado, no one else confirmed his observations, and they were sharply criticized by Clinton College (New York) astronomer C. H. F. Peters. Nevertheless, Watson remained absolutely convinced of what he had seen, and his move from Ann Arbor to Madison in 1879 was partly motivated by the prospects of obtaining better instruments with which to further his search for Vulcan, which became the obsession of his later years. He was in the process of constructing an underground solar observatory from which he hoped to see stars near the Sun in broad daylight when he died, unexpectedly, in 1880. Though it is now known that Vulcan does not exist, Watson's observations at the July 1878 eclipse remain problematic; it is probable that he observed at least one and possibly two pygmy comets in the neighborhood of the Sun.

Program listing for Monday