One can at least instantiate a Rhino Sun system and compute sun vectors from this (that’s what I did here). You should also be able to fiddle with the sun system within the Rhino document from e.g. GHPython. I’d think it’d be similar to editing lights, clipping planes etc.
Which algorithms are being used and their accuracy is a bit more unclear. For full transparency and the ability to reference methods/papers, I’d also go with Ladybird/Honeybee.