You might think that the day of the Full Moon would be the perfect time to familiarize yourself with the surface of our sole natural satellite. From Earth, we can only ever see one side of the moon, but during a full moon, all of that side is visible, after all. But if you’re trying to get a good look at the Moon’s craters and “seas,” the Full Moon is no friend of yours. At that point, the Moon is at its brightest, with everything pretty much equally lit. To get the best view of a lunar feature, it’s actually ideal for the sun’s light to cut across it at an angle, showing the land formation in stark relief. To view lunar features with your binoculars under these conditions, you want to look for them just after they become illuminated, when they’re still right on the line separating lunar day from lunar night (a line called “the terminator;” presumably the term came before the movie). Here are a few major lunar landmarks you can pick out with your binoculars as the moon progresses through its phases.
Mare Fecunditatis, Mare Tranquillitatis and Mare Serenitatis: The Seas of Fertility, Tranquility and Serenity are the real stars of the first few phases of the moon. They come into view as the Waxing Crescent Moon turns into the First Quarter Moon–first Fertility, then Tranquility, and last, Serenity. Despite the first part of their names, they aren’t actually seas, but huge, dark lunar mares, basaltic plains that were formed by volcanic eruptions long ago. Look for three large spots in a diagonal row, working their way from around the middle of the Crescent Moon up toward the lunar north pole. These features will remain visible until they fall on the dark side of the terminator (seriously, how ominous does that sound?) as the Moon moves into its Waning Gibbous and Last Quarter Moon phases.
Copernicus Crater and Tycho Crater: Things get more exciting as the First Quarter Moon turns into the Waxing Gibbous, revealing enormous pock marks on the Moon’s surface. At more than fifty miles in diameter, Tycho Crater is hard to miss. Look at the lower half of the Waxing Gibbous Moon. See the light-colored circle with bright rays extending out from it in every direction? That’s Tycho. Copernicus Crater is even larger, coming in at nearly sixty miles across. It’s higher up on the Waxing Gibbous Moon, a big bright spot surrounded by the darkness of lunar mares. Both craters remain visible during the Full Moon, until lunar night overtakes them (it sounds ominous even when I don’t say “the terminator,” doesn’t it?) as the Moon transitions from its Last Quarter phase to the Waning Crescent phase.