Transit of Venus Observatory

In 1769, an international scientific effort was organized to observe a transit of Venus in order to determine the size of the solar system. This rare event, when Venus passes in the front of the Sun’s disk, makes such calculations possible when measured from widely separated sites. The American Philosophical Society sent Owen Biddle and Joel Bailey to Lewes from Philadelphia to establish a temporary astronomical observatory to record the transit on June 3, 1769. Their observations, combined with measurements from other astronomers, placed Lewes in the forefront of 18th-century astronomy. The observatory was located near this site.