Manifestations and possible sources of lunar transient phenomena /LTP/

An observing program designed to monitor sites of lunar transient phenomena (LTP) is discussed in the context of the distribution of LTP sites and possible sources of the events. It is noted that the distribution of LTP sites shows a strong preference for the edges of maria and a paucity in the north and south highlands, suggesting a relationship with dark smooth material known to be volcanic and implying internal activity at the sites. The observing program, which is aimed at those LTP described as brightenings, has been conducted to determine the normal brightness of each observed feature for all phases of a lunation and to establish a quantified 'seeing' scale. The procedure for establishing the albedo scale of a given feature is outlined, and some observations of the crater Dawes are analyzed as an example.