twenty-seven
day moon
The Moon's thin crescent will tonight only be visible for a short while before sunrise, low in the east. As the Moon appears close in the sky to the Sun, it follows that much of the moonward-facing side of the Earth is sunlit. Consequently there is a great deal of "earthshine" reflected back onto the Moon (many times brighter than a full moon shining on the Earth) making the dark portion of the Moon's disc faintly visible. This phenomenon - a dim full phase combined with a thin sunlit crescent - is sometimes called the "new moon in the old moon's arms".

Pythagoras Close to the northern cusp, the class 1 walled plain Pythagoras is a prominent feature, showing fair contrast between shadow and highlight.

At the opposite end of the crescent, about 1/6 of the way up from the southern cusp, another walled plain - the large class 5 Schickard - is now just a smooth hollow on the terminator. Between Schickard and the limb lies the highly foreshortened class 2 Inghirami. Midway between here and the southern cusp, another class 5 walled plain, Bailly, occupies almost the full width of the Moon's crescent. It is the largest crater on the entire nearside.

With favourable libration, a series of slight bumps may be seen on the limb between the midpoint and about 1/4 of the way up from the southern cusp. These are the Cordillera Mountains - the outer ring wall of the farside Mare Orientale, which itself may be glimpsed with exceptional libration.