The Principal Investigator (PI) is a previous Presidential Young Investigator who has used much of his previous award to design and build a robotic telescope to monitor the light output of supernovae with time. The PI now proposes to complement his light curve work with a coordinated program of high dispersion spectroscopy. His goal is to establish a far greater degree of homogenity in the classification of supernovae than has existed in the past in order to define the evolutionary histories of these objects, as will as the characteristics of their progenitor stars. This work will help determine the mass ranges of stars that are apt to lead to certain kinds of supernovae. It will provide new estimates of the dispersion of observable properties, such as luminosity, leading to a more confident use of supernovae as "standard candles" and to improved distances of external galaxies.
