https://en.wikipedia.org/wiki/Axial_tilt#Solar_System_bodies gives the axial tilt of all planets with two decimal precision, but how and when were they measured so precisely ?
I guess it's "easy" for Mars, Jupiter and Saturn (thanks to the rings ?) but how was it measured for Venus under its clouds, or Uranus + Neptune that are so far away ?
Links to scientific publications would be appreciated.
Thanks