Earth from Apollo 8.

As well as the famous ‘Earthrise’ image, Apollo 8 brought back striking photographs of the Earth alone. Although not quite full (‘gibbous’ is the term), this was our first sight of the Earth as a distant blue marble – or, as the Apollo crew thought of it, a Christmas tree ornament. The image was used by John McConnell in the Earth Flag, as used in the first Earth Day in 1970.