cosmology is a branch off of astronomy, cosmology is the study of large scale properties of the universe as a whole. Astronomy is the study of celestial objects, such as stars, planets, galaxies, etc.
Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is "the scientific study of the large scale properties of the universe as a whole."
