[radarsat1]

Great write up, that was a fun read.

In understanding how the rotation was implemented, it took me longer than it probably should have to realize that the normal map (which I think of in terms of lighting) is actually a radial position on the sphere.

I had to go back and forth with the final and original code a few times, and finally noted that "n" gets renamed to "point" when it becomes an argument to colorLookup.

This dual usage of the normal for lighting brightness calculation and as a radial position on the sphere surface for looking up the color makes sense in retrospect but is also a somewhat subtle aspect that you might want to address more explicitly in your text instead of just silently renaming the variable in the code.