Resolved Physically Based Sky - Rotating around Polar star?

Tying to create realistic night sky with HDRP.

Physically Based Sky have Space Rotating (Vector3) and Texture (with some stars).

The question is... How to rotate my night sky around Polar Star (some specific star on Texture) with Space Rotating (Vector3)?

Is it possible? Or maybe need a feature request for this, Unity?

 

You can dig into astronomical coordinate systems if you want scientific accuracy or you can spin the space skybox around an axis you can manually set. Could maybe bruteforce finding the right values at runtime (if not easy, point a camera at the star and use its rotation/use debug draws etc.)

It'd be too specific to implement by Unity and the means are already here to implement it if you know what you're looking for.

 

In case your star map is already in celestial coordinates (like this one https://svs.gsfc.nasa.gov/4851) you can simply rotate it along the Y axis, the polar star stays always at the very top.

 

Rotating only one axis works in places like Equator and North/South poles... If Polar star at very top, we are in Arctica. But my game is not about Polar Bears.

 

Then just multiply it by another rotation representing your position on the planet, something like this;

Code (CSharp):

1. Vector3 spaceRot = (Quaternion.Euler(90 - latitude, 0, 0) * Quaternion.Euler(0, dayTime, 0)).eulerAngles;

 

Good, Quaternions works like a charm. Thank you all for the answer!