Paris Observatory, France — 28 August 1686
Mystery planetoid near Venus
A second observation by Cassini of the supposed satellite of Venus, which would later be named “Neith.” Venus was a morning “star” at the ltime, with heliocentric longitude 59° and elongation 38°. The object was estimated to be A the diameter of Venus and it showed the same phase as Venus. Cassini then revealed his two sightings.
Source: “The Problematical Satellite of Venus,” in The Observatory 7 (1884): 222-226. Case: W253