Here is a snapshot of Rukl 20 with the Sun 5 degrees above the horizon at the center. The lunar surface is derived from ldem_64.jp2 produced by the LOLA science team. The surface should be tilted about 15 degrees away from the view but it is not. 15 degrees x 15 degrees: 15 to 30 N, 15 to 30 W. Lambert is the large solitary crater at the upper right.
Quoting from the Wikipedia entry for Lambert Crater: “Just to the south of Lambert’s ramparts is the lava-covered rim of a crater that is almost completely covered by the mare. The diameter of this ghost crater is slightly larger than Lambert, but it is difficult to spot except when the Sun is at a very low angle. The feature is designated Lambert R.”
This image is from the Moon Wiki, the Rukl-based Index to the-Moon Wiki created by Jim Mosher.
It’s an idea to recreate the atlas in 3D and animate the lighting.
I believe the lighting artifacts are due to a one percent specularity of the surface in the animation.