This is a good question. I have not looked, and the closest thing I have done is to measure the color temperature and intensity according to my camera for direct sunlight just before sunset (seems to be about 2700K, 1900lx).
I would think that you could get a decent estimate using SMARTS if you adapted the input file to a ray going through a lot more atmosphere, but I’m not sure. I haven’t looked at the code and it might do something like make approximations that only work for short path lengths or low optical densities or something.
This is a good question. I have not looked, and the closest thing I have done is to measure the color temperature and intensity according to my camera for direct sunlight just before sunset (seems to be about 2700K, 1900lx).
I would think that you could get a decent estimate using SMARTS if you adapted the input file to a ray going through a lot more atmosphere, but I’m not sure. I haven’t looked at the code and it might do something like make approximations that only work for short path lengths or low optical densities or something.