Lunar Luminescence

Abstract

IN a recent article, Kopal¹ has directed attention to a report by Sir William Herschel² of ‘volcanoes’ in the neighbourhood of the lunar crater Aristarchus seen in April of 1787. Both he and Middlehurst³ note the similarity between Herschel's description and two recent reports by Greenacre^4,5 of reddish luminescence near Aristarchus in October and November 1963. In Table 1 are listed 16 additional transient luminescent events in the vicinity of Aristarchus observed during the period 1783–1963. Included in the second column of Table 1 are the colour, the visual magnitude, and the dimensions of those luminescent spots for which these data were reported. Of the 19 observations listed, the first 16 were made 2–6 days after new Moon; that is, when Aristarchus was on the dark side of the lunar surface far from the terminator. The three most recent observations were made shortly after full Moon, with the crater in sunlight. In addition to these reports, the literature contains references to luminescent events in the vicinity of several other lunar features including Pitatus²³, Heraclides Promontory²⁴, Alpine Valley²⁵, Carlini²⁶, Alphonsus²⁷, and Kepler²⁸. All these events, except those involving Alphonsus and Kepler, were on the dark side of the Moon. The latter two events as well as the luminescence of Aristarchus observed by Kozyrev²² in 1961 were recorded photographically. Several of the remaining events were observed visually through different telescopes by two or more independent observers.