Briefly, the Moon acts like a car travelling around a traffic roundabout where the same side always faces the centre as a property of its orbital motion. Call it revolution.
There was a purpose in introducing Kepler's perspective on a non-rotating yet orbiting Moon as his Somnium work lends itself to misinterpretation on that account. His revolution is orbital motion and uses the poles of the ecliptic, which the Earth also has, as inferred by the ecliptic plane.
https://books.google.ie/books?id=OdCJAS0eQ64C&pg=PA80&lpg#v=onepage&q&f=false
The RA/Dec framework tries to dispense with the ecliptic poles and tries to gauge everything off the daily rotational characteristics on the Earth like so.
https://www.youtube.com/watch?v=WvXTUcYVXzI&t=104s
Contributors here should already see there are complex issues involved, and the least of them all is a discussion on the Moon's orbital motion of the Earth. The first Sun-centred astronomers worked off the ecliptic plane and poles rather than the clockwork solar system, which works off RA/Dec conceptions.
"The third movement is the declination movement. For the axis of daily rotation is not parallel to the axis of the great circle but is inclined to it by such a part of the circumference, which in our time is almost 23 and a half degrees. Thus, the Earth's centre always remains in the plane of the ecliptic, i.e. on the circumference of a great circle, and its poles revolve, drawing small circles on both sides around the centres equidistant from the axis of the great circle. This movement, too, takes place over almost a year and is almost equal to the revolution of the great wheel" Copernicus, Commentariolus.
All this becomes important when dealing with Kepler's representation of Mars over sixteen years and, once again, misinterpreted by a mathematician. It does involve what is called frames of reference in modern terminology.
https://en.wikipedia.org/wiki/Johannes_Kepler#/media/File:Kepler_Mars_retrograde.jpg
[ I imagined this would not be posted to Google Groups given that this discussion group is meant to be frozen in time.]