DustbringerAdmiralThrawn

Check out Nicole Glover's Murder and Magic series. It is set in post Civil War Philadelphia with the two main characters used constellation magic when they were conductors on the underground railroad. The short of it is drawing certain constellations with your finger provides certain results (i.e. one provides light, one provides projectiles, one a shield, etc.). It can serve as an example of what you like and dislike in building your own.