…continuedA Month of Moonwatching
Prominently splashed across the eastern half of Oceanus Procellarum (Ocean of Storms) is one of the Moon's grandest features. Copernicus, a spectacular 58-mile-wide crater, is distinguished by deeply terraced ramparts that rise 3,000 feet above the surrounding plain. The crater's interior has a broad, relatively flat floor with conspicuous central mountains.
The Moon's disk is now gibbous, a rounded shape seen for several days before or after full Moon.
Tucked inside the northern side of Mare Humorum (Sea of Moisture) is the prominent flooded crater Gassendi. It spans almost 70 miles, has walls rising to 6,100 feet, and contains a number of central peaks. The central peaks are evident, but Gassendi has a gap in its southern wall, where the shadows go from black to light gray. A network of clefts, seen as thin streaks under high power, crisscrosses the crater floor. Some of these may be challenging to spot, depending on the size of your telescope and the steadiness of the atmosphere. Jutting into the northern rim is the craterlet Gassendi A. It's about a third the size of the main depression, yet its walls are almost twice as high. And while in the area, don't overlook the spectacular set of raised rilles that run across Mare Humorum's broad floor, on the side opposite Gassendi.
Full Moon (Day 14)
When the Moon is bright and full, I find binoculars to be ideal for studying the rays that spray out like bright spokes from prominent lunar craters. Near the southern limb is Tycho, a 53-mile-wide crater that's the hub of the Moon's best ray system. Another set radiates from Copernicus. See if you can detect these ray systems with your eyes alone.
Because of the lack of shadows during a full Moon, it's a challenge trying to identify features that a few days ago were near the terminator, when shadows helped define their shape. However, the straight-on sunlight makes it possible to observe other characteristics in the landscape particularly well. For example, darker shadings become apparent in the maria variations that are due to differing ages and compositions among these ancient volcanic flows. To me Tranquillitatis looks darker overall during full Moon than other maria do, and the eastern and southern shores of Serenitatis look darker than its interior. Check for yourself.