Implementing an atmospheric shader in three.js is a fun way get an understanding of the interaction of the different scattering components, light, and observer’s position. Plus you get a pretty cool effect to play around with after you’re done.

The explanation that made it click for me a while ago was by someone who implemented a shader https://www.alanzucconi.com/2017/10/10/atmospheric-scatterin... — the explanations that don't end up producing an image all seemed to skip over one detail or another.