Found

    Galactic year

https://sites.google.com/view/abraham-c/found/galactic-year

See also (background):

https://sites.google.com/view/et-background/milky-way/Rotation-period

233.050.855,4 years ... https://sites.google.com/view/a-code-f-001/files/26-xxx/26-9xx/26-96x/26-969