Leonardo da Vinci's careful descriptions of the reflection of light by the moon inspired the author to compose a piece for choir on ways of perceiving the moon. In The Two Moons, Leonardo's words are contrasted with two additional texts: facts from a textbook on astronomy and a poem by Denise Levertov. The author discusses the challenge of transforming text and idea into musical sound. Further he discusses exploring natural phenomena by means of parallel efforts in art and science.