Human error

It was fortunately on the night side of Earth at the time, and in a position of bright illumination by the sun. Two of the observers had movie cameras attached to their ten-inch mirrors.    Raymond Fisher Jones (15 November 1915 – 24 January 1994) was an American science fiction author. He is best known for his 1952 novel, This Island Earth, which was adapted into the eponymous 1955 film.