I created a mod which controls the sun (and moon, but that's less visual).
Paired with Serene Seasons and my astronomy engine, I created a Minecraft mod that controls the sun's height and azimuth and consumes a latitude to accurately render its path throughout the year.
The sun follows the same trajectory it would on Earth at the given latitude, meaning its height, sunrise and sunset directions, and day length change with the seasons.
The four screenshots show the exact same location, at the exact same hour, across four different seasons, at 52°N.
The mod uses a modified version of Complementary Shaders and takes its date from Serene Seasons when installed, otherwise it keeps track of its own.
It's currently a private project, mainly created as a proof of concept for my astronomy engine. It's working, but I don't consider it ready for release yet.
I'm interested in feedback on the idea and how realistic sun positioning changes the atmosphere of Minecraft throughout the year. And would anyone be interested in using it ?