unknown location — 20 May 1759
Unexplained satellite of Venus
Astronomer Andreas Mayer reported an observation of a planetoid object seemingly orbiting Venus.
Source: Mayer’s observation first appeared as a very brief footnote in his book, Observationes veneris gryphiswaldenses (1762), 16-17. The full report was first published by Johann-Heinrich Lambert in 1776 in Astronomisches Jahrbuch oder Ephemeriden fur das Jahr 1778 (Berlin, 1776), 186. Case: W295