The Los Alamos National Laboratory KrF Aurora laser optical system is described. Conceptual, first-order, and detailed designs are presented for the major 248-nm ultraviolet optical subsystems. In Aurora, a 5-ns front-end pulse is replicated and time encoded into a 96-beam, 480-ns pulse train, angle encoded, amplified, and then time and angle decoded so that all the 5-ns pulses arrive at the target plane simultaneously. The encoder and the centered optical system that directs the pulse train through the amplifiers have been installed, one major alignment system has been built and tested, and most decoder optical components have been designed and ordered. The plan is to have the entire optical system installed and initial integration completed by October 1987.