Samuel Dunn's drawing of Venus in contact with the sun in 1769

Object notes   Associations

A detail from the large plate which appeared in Samuel Dunn's "A Determination of the Exact Moments of Time" (London, 1770). Dunn attempts to record exactly the appearance of Venus when in contact with and close to the limb of the Sun.

Far from being a perfect circle Venus appears as a dark ball with feathery threads reaching out to the edge of the sun. This phenomenon (the "black drop") caused much uncertainty over the exact timing of Venus's contacts with the limb or edge of the Sun.

The printing is very dark and it is difficult to read the text that appears in the body of Venus and in the background sky beyond the Sun.

Related Objects

• Samuel Dunn's analysis of the 18th-century transits

Source

Object contributed by Museum of the History of Science, University of Oxford