Phases of the Moon

Every night that we look at the moon during a month, we see a different amount of it lighted — and this lighted area moves across the moon — starting at the right side and ending at the left side.

Moon Photo in High Contrast

The high-contrast section of the moon that McCarthy referred to is called the "lunar terminator" — the long line in the sand (or regolith, if you prefer) that divides the moon’s Earth-facing side between darkness and light. This terminator line moves around constantly depending on the phase of the moon, revealing or concealing new sections of the lunar surface each day. Because the terminator line heightens the contrast between the light and dark sides of the moon’s face, shadows look elongated and intensified in craters closest to the terminator.
With this in mind, McCarthy trained his camera on the craters closest to the lunar terminator every night for two weeks as the moon waxed toward complete illumination. By the time the moon was full, McCarthy had a series of high-contrast, high-definition photos of every crater on the moon's Earth-facing side. Blending them into a single composite image was "exhausting," he wrote, but ultimately resulted in the gorgeously detailed shot seen above — an image that McCarthy calls the "all terminator" moon.
This impossible composite can't really be considered a true photograph of the moon, but the finished whole certainly amounts to more than the sum of its shady-cratered parts.
Source: https://www.space.com/terminator-moon-composite-image.html