Barnard’s Mysterious Star Near Venus

Edward Emerson Barnard is regarded as one of the greatest astronomical observers of all time, who discovered numerous comets, the fifth satellite of Jupiter, and pioneered the wide-angle photography of the Milky Way. Given his well-earned reputation as the most judicious and reliable observer of his time, an observation of a seventh-magnitude star near Venus with the 36-inch refractor of Lick Observatory on 13 August 1892, which has never been explained, has long intrigued and baffled astronomers and historians of astronomy. Barnard recorded it incidentally while searching for Venusian satellites, and though at the time no doubt regarding it as an ordinary field star, he later established it did not correspond in position to any known star. As was usual with him for doubtful observations, he did not publish, at first. Yet later he did, for reasons unknown, fourteen years later. In this paper, we consider Barnard’s observation in the context of his career and struggle to establish his reputation as an observer, and also summarize the results of our own investigations to try to determine, at long last, just what he likely saw. In particular, we have exhaustively listed and tested all possible astrophysical, atmospheric, and telescopic mechanisms for a transient source (including novae, comets, asteroids, variable stars of all types, and various classes of ghost images), and we refute them all at a high confidence level. The only remaining possibility is that the problem comes from some ordinary error in Barnard’s report. We conclude that Barnard must have seen the 11th magnitude field star (TYC 1348-1601-1) and simply reported its magnitude as brighter than it actually is (due to his lack of any comparison star in twilight and his unfamiliarity with the 36-inch telescope)

Astrometry · Celestial sphere · Milky Way · Observatory · Refracting telescope · Telescope · Historical Astronomy and Related Studies · History and Developments in Astronomy · History of Science and Natural History