Morphological studies of nighttime dark current data from the Nimbus 4 backscattered UV experiment clearly indicate enhancements during the period of the full moon. This analysis is based on processed and filtered data which have other known perturbations induced by energetic particle events. In order to obtain truly quiescent dark current background values for the 5-day study intervals centered about several full moon sequences and for the corresponding new moon intervals, the data were further screened so that isolated elements showing spurious or abnormal enhancements could be removed selectively (~3%). The results demonstrate the presence and uniqueness of a lunar signal, induced by atmospherically backscattered UV radiation. On the Nimbus 4 instrument this signal is not sufficiently strong to provide an accurate map for global nighttime ozone. However, these results do suggest this as a potential application for future, more sensitive instruments.