Named in honor of William W. Morgan {1906–1994}, whose career at the Yerkes Observatory since 1926 has been devoted to morphology, the classification of objects by their form and structure. He and P. Keenan {see planet  (10030)} introduced stellar luminosity classes and the two-dimensional classification of stellar spectra strictly on the basis of the spectra themselves. With D. Osterbrock {see planet  (6107)} and S. Sharpless he discovered spiral arms in the Galaxy from spectral studies of O and B stars. Morgan invented the UBV system of magnitudes and colors, and with N. Mayall {see planet  (2131)} he developed a spectral classification system for giant galaxies. (M 15089) _ _.