Newton drew what he thought, not what he saw.
what we actually do observe, is a close to earth, 2D representation, of a 3D object in far space. as only light can travel through space, only light IS the information, shadows do not reflect, nor travel, shadows remain static, on the object's surface where created. what we do observe is a mix of light, and the absence of light, completing the circle of the moon's circumference, with our minds, as seen on the edge of our atmospheric screen.