The Morgan classification aka Yerkes classification (a galaxy classification scheme) classifies galaxies by their prominent stellar spectral class(s), then according to morphology, and then according to the angle of view.
|af||a to f class|
|fg||f to g class|
|gk||g to k class|
|D||other rotational symmetry (e.g., lenticular galaxy)|
|cD||extremely large D galaxy|
|L||low surface brightness|
|N||small bright nucleus (N galaxy)|
|Ep||elliptical with dust absorption|
Inclination (as seen from Earth) is indicated by a number 1-7, 1 for face-on to 7 for edge-on.
Note that variants on the phrases Morgan classification and Yerkes classification are also used for classifications of other types of astronomical objects, such as classifications of stars and of galaxy clusters.