This would further contextualize the position of solar system objects as relevant to the players on the surface: 

I discretized a surface plane (at 1x1 meter intervals) and placed an 800 Dton sphere over it, then did an intersection test between each surface point and the sun to see if the sphere is blocking the sun and it does look much like a shadow creeping across the ground, playing forward at 2 hours per second. Positioning is the same as the last render, +55 degrees latitude. 

Ideally I would voxelize the playing volume and be able to determine lighting conditions at each point in the volume, but the first goal will be to be able to load complex geometry and rapidly compute lighting conditions across it, as well as be able to display terrain in so that the players have good context of their environment. 

And now that timothy has posted his traveller adventure report, I have some reading to do!