Lunar detail is visible when the Moon is near quarter phase than when the Moon is at full phase. This happens for many reasons, but primarily because the Sun is hitting the moon on the side we can see when it is near its quarter phase. The many figures on the Moon, such as mountains, cast shadows when the Sun hits them, making these details on the moon much more profound than they are when there is no Sun or shadows. The brightness, mixed with the shadows and the fixed markings on the moon like craters and mountains, make the Moon most visible when it is at quarter phase.
