A composite chart is the study of the relationship between two people. It's the point where two birth charts come together as one singular chart. It's based on the date, time, and place of birth of the two persons involved, and it represents an astrology chart of the dynamics between them. A relationship synastry chart examines how well you're going to get along based on an in-depth comparison of each planet in both charts. A composite chart takes the energy of the relationship and gives it its own persona, if you like, examining how it's likely to act and evolve. While a relationship synastry chart looks at compatibility, a composite chart looks more at the karma and the destiny of a particular pairing.