What is retrograde planetary perihelion precession?

[magheera]

I know what each word mean independently, I'm just confused as to what sort of motion is trying to be described as a whole.

[tiny-tim]

hi magheera! :smile:

perihelion precession means that the perihelion moves slightly each orbit

usually, this is prograde, which means in the same direction as the orbit itself

retrograde means the perihelion moves in the opposite direction to the orbit

[magheera]

fantastic! Thanks so much.