According to a saying, what color in the night sky is a sailor's delight?

The common phrase "red sky at morning" is a line from an ancient rhyme often repeated with variants by mariners and others: "Red sky at night, sailors' delight. Red sky at morning, sailors take warning." The concept is over two thousand years old and is cited in the New Testament as established wisdom that prevailed among the Jews of the 1st century AD by Jesus in Matthew 16:2-3.

Source: Wikipedia