The rings appear to be near flat to our viewpoint and the lightsource is up and only slightly behind the planet - so the moons shadow would be lower and stretched, (your doing this in a 2d program?? Now I'm really amazed.... )
I'm not sure I agree with that... I think that based on the distance of the moon from the rings, the shadow is about right... unfortunately, I don't have any 3d software to test this stuff out in...
That's a week and 2 days of progress - I've done a few more things today - but I'm somewhat taking today off on creating on that so I don't burn out before finishing (and I have some REALLY hard to create parts coming - and some will have to have UV textures in order to look right)....