Manifestations and possible sources of lunar transient phenomena (LTP)

Several different manifestations of lunar transient phenomena (LTP) have been reported. These include: (1) brightenings - both sudden and slow, (2) reddish - both bright and dull, (3) bluish -both bright and dull, (4) fairly abrupt dimmings or darkenings, and (5) obscurations, which may be accompanied by any of the other four manifestations. Approximately 200 lunar features exhibiting such anomalies have been reported at least once, but 80% of all observations are found in less than a dozen sites and 60% are found in about one-half dozen sites. An observing program is being conducted for the Association of Lunar and Planetary Observers which is designed to monitor the LTP sites, the seismic epicenter sites and non-LTP comparison sites. It addresses the ‘brightenings’ category of observations and is designed to establish normal brightness of each observed feature for all phases of a lunation. It also seeks to establish a quantified ‘seeing’ scale. About one-half dozen observers have reported albedo measures (estimated from an albedo scale set up by each observer). The most extensive new data on albedo versus age (phase of Moon) are for the crater Dawes. Several LTP effects have been discerned in Dawes. In addition, seeing estimates, based on the behavior of a star's diffraction disk, provided some unexpected results when disk behavior is compared with other subjective estimates of seeing.