Tranquil Sunshine
Explanation:
Last month, LPOD featured KC Pau's image of a full Moon view of Mare Serenitatis; here is the companion, shot on the same night, of Mare Tranquilitatis. Once again when the sun is overhead and shadows disappear, a less familiar Moon appears. As you sweep your eye over the mare, it becomes obvious that it is not all the same hue. A series of rather large light circles extend from near Arago to Carrel to Jansen (see mouseover). These are the areas of slightly higher surface structures that I call the Lamont-Gardner Megadome Alignment. Another more delicate type of feature, only visible near high noon, is a dark rim around some craters. Dawes has such a collar, as do the five craters I've arrowed, but the really amazing dark ray crater is Dionysius - take a look! These dark collars and rays are due to the crater ejecting dark mare material that must be beneath the lighter surface rocks. Finally, notice the bright-rimmed craters. Proclus, with its asymmetric rays is obvious, but also look at Theon Junior and Senior. Bright rimmed craters expose fresh surfaces (due to landslides) that have not yet been darkened by solar radiation. These are some of the youngest craters on the Moon.
