A connected sun and moon tattoo represents the joining of two opposites. It could show the joining of good and bad, or male and female.
The sun is considered a masculine design, because of its strength. It is thought to be one of the strongest forces in history and represents many things, such as courage or life. The moon is considered female, and signifies mystery or magic. It also symbolizes the way human nature changes quickly. Joining the two together creates a design of opposites. This could show unity, love, yin and yang or anything else the tattooed person chooses.