Rome, Italy: Unidentified planet — 2 October 1839
Astronomer De Cuppis of the Royal College: unknown body similar to a planet passes in
front of the sun. This is one of the main observations selected by Le Verrier to compute his orbit of Vulcan. The object was “a perfectly round and defined spot, moving at such a rate that it would cross the sun in about 6 hours.”
Source: E. Dunkin, “The suspected Intra-Mercurial planet.” Monthly Notices of the Royal Astronomical Society 37 (February 1877): 229-30. 426. Case: W379