A cardboard box with a pinhole in one end and a sheet of vellum on the backside, so that the sun fluttering among the trees is projected onto it. This moving image edit is derived from about 4 or 5 takes on the day venus was to cross the sun's path. As it turned out I got the day wrong, but it wouldn't have mattered as the image that formed on the vellum was so soft and wispish and the trees were in the way that there was no chance whatsoever venus could be seen passing by.