Triangulum galaxy
In the French astronomer Gérard de Vaucouleurs' revised Hubble Sandage (VRHS) system of galaxy morphological classification, the Triangulum Galaxy is classified as type SA(s)cd. The S prefix says that it is a spiral galaxy. The A is assigned when the center of the galaxy lacks a bar-shaped structure, unlike SB class barred spiral galaxies. American astronomer Allan Sandage's "(s)" notation is used when the spiral arms emerge directly from the center, instead of an inner ring like an (r)-type galaxy. Finally, the cd suffix describes the openness of the arms. cd means loosely wound arms.