So Ike is close enough to Duna, and both are far enough from Kerbol, that if this system were real the shadow would still have a very sharp edge to it? Huh, the more you know...
I don't know if the engine can support it, but some dithering or something around the edges of the shadow would help a lot to remove the fakeness that the shadow's sharpness produces, even if it wouldn't be completely realistic. it really looks like someone took a solid black circle of construction paper and just pasted it over Duna.
Regardless, really happy with the addition of shadows. It's another one of those features that I didn't know I needed until I watched the Mun's shadow on Kerbin, but now I doubt I could be fully satisfied playing this game without it.