<P> Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance . There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence, devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage . </P> <P> The Hubble sequence is a morphological classification scheme for galaxies invented by Edwin Hubble in 1926 . It is often known colloquially as the "Hubble tuning - fork" because of the shape in which it is traditionally represented . Hubble's scheme divides galaxies into three broad classes based on their visual appearance (originally on photographic plates): </P>

Who created the classification system that divides galaxies by shape