Credit: © The Royal Society
Image number: RS.9604
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Ingress of Venus during the 1769 solar transit
Date
12 June 1769
Creator
William Hirst (British) , Astronomer, Astronomer
Object type
Archive reference number
Material
Dimensions
height (painting): 195mm
width (painting): 325mm
width (painting): 325mm
Subject
Content object
Description
Sketches of the Transit of Venus at the beginning of the 1769 event. Ten figures [only nine of which were used in the eventual published plate], from the earliest showing of the planet to the appearance of the “black drop” effect. Hirst observed using a 2-foot long reflecting telescope to x55 magnification. Eight individual pieces of paper pasted onto a single backing sheet. With pencilled instructions to the engraver. Not signed.
Hirst’s textual account gives the following details: “The first intimation which I had of the near approach of the planet, was by the sudden appearance of a violent corruscation, ebullition, or agitation of the upper edge of the Sun...I plainly saw a black notch breaking in upon the Sun’s limb, and which seemed a portion of a much less sphere than that of Venus...The same phaenomenon of a protuberance, which I observed at Madras in 1761, at both internal contacts, I observed again at this last transit: at both times, the protuberance of the upper edge of Venus diminished nearly to a point before the thread of light between the concave edge of the Sun and the convex edge was perfected...but Venus did not assume its circular form till it had descended into the solar disc...”
The illustration appeared as plate 10 and 11 of the published paper “Account of several phaenomena observed during the Ingress of Venus into the solar disc” by William Hirst, Philosophical Transactions of the Royal Society, vol.59 (1769) pp.228-235.
Hirst’s textual account gives the following details: “The first intimation which I had of the near approach of the planet, was by the sudden appearance of a violent corruscation, ebullition, or agitation of the upper edge of the Sun...I plainly saw a black notch breaking in upon the Sun’s limb, and which seemed a portion of a much less sphere than that of Venus...The same phaenomenon of a protuberance, which I observed at Madras in 1761, at both internal contacts, I observed again at this last transit: at both times, the protuberance of the upper edge of Venus diminished nearly to a point before the thread of light between the concave edge of the Sun and the convex edge was perfected...but Venus did not assume its circular form till it had descended into the solar disc...”
The illustration appeared as plate 10 and 11 of the published paper “Account of several phaenomena observed during the Ingress of Venus into the solar disc” by William Hirst, Philosophical Transactions of the Royal Society, vol.59 (1769) pp.228-235.
Associated place