Lunar Day Twenty-One

Abstract

Tonight we start with a look at sunset over one of the most often studied and mysterious of all craters - Plato (Figs. 22.1 and 22.2). Located on the northern edge of Mare Imbrium and spanning 95 km in diameter, Class IV Plato is simply a feature that all lunar observers check because of the many reports of unusual happenings. Over the years, mists, flashes of light, areas of brightness and darkness, and the appearance of small craters have become a part of Plato’s lore. On October 9, 1945 an observer sketched and reported “a minute, but brilliant flash of light” inside the western rim. Lunar Orbiter 4 photos later showed where a new impact may have occurred. While Plato’s interior craterlets average between less than one and up to slightly more than 2 km in diameter, many times they can be observed - and sometimes they cannot be seen at all under almost identical lighting conditions. No matter how many times you observe this crater, it is ever changing and very worthy of your attention!