First off, I would be suspect of and cautious about any claim to proprietary ruler ships by any of the Planets or Luminaries to any of the Astrological Parts.
I've yet to see any examples, by direct demonstration or by citation to such, from anyone to substantiate this claim.
In addition, in my estimation and opinion, the "jury is still out" as to whether every one of the Astrological Parts indeed is of affect to everyone, too.
I have found, from my many years of study that the late 20th century American clairvoyant, the renowned, Edgar Cayce, to be correct as to regarding the readings in which he spoke about the amount of influence of the Planets have on mankind in general. That, according to Edgar Cayce, most people are affected by only two to six of the Planets and those numbers, most very likely, are including the influence of those Planets yet to be re-discovered and were unknown in his time and still presently so in this age.
There is a disagreement as to whether that statement included the Luminaries but I am of the camp that is certain that He was referring to the planets from Mercury to Pluto and that the Luminaries are a ''given", as how could they not affect everyones' life on that level as everyones very life is dependent upon their physical presence and the influence they have upon the earth?
As Cayce added the words, "...and all angles to the Ascendant", as to what astrological influences do assuredly have effect on people, I have taken that to mean all Astrological Parts that have the Ascendant as the "Personal Point" of the formula from which the Part is derived from...and at this time, to most likely be regardless of whether any particular planet isn't a direct influence upon anyone in particular astrologically.
At this time I believe that those planets that are of influence on any given person to have an increased weight, or amount of influence, of compulsion, upon any astrological part in which it is also involved in the formula of.
What I do personally find open to debate is whether it is the "Significator" or the "Trigger" that has preeminence in the formula and be that there actually is a, what might be labeled as, a "domain of ruler ship", I have found that the planet that is in the position of being the trigger, when it is also of the more outer region, or orbit, of the two is decidedly the dominate influence.
I agree with Jupiter Asc, in that the House placement does have it's due to be contended with and that the "promise of the natal chart", or "overall tenor" as I am more apt to label it, is also a factor that has to be addressed.
I don't recommend "skyscript" as a reference for such matters though. The proprietor of that website makes no secret of the fact that she is neither Degree Symbolism friendly nor will admit that the Astrological Parts are "symbolically active", as to which I have given dozens of demonstrations to the contrary, that indeed in fact they are. Nor has she shown any indication of admitting that some of the prevailing titles given some Parts and what influences that are said to be of their domain are questionable, if not altogether downright dubious, as I and a few other members of this forum...notably, and most praiseworthy in particular, Phoenix Venus, have questioned, challenged, examined, analyzed, assessed and derived more appropriate identifications of realms of influence, through given demonstrations and evidence by examples through the natal charts of well known historic personages and those of current fame and or public notoriety.
All of which I keep listed in a thread, I originated, here in the Degree Symbolism forum that invites all to contribute their own findings and give demonstration of as for, reason to substantiate any "Traditional" or published title and influence, that which is being declared of sound integrity or to challenge same and provide the same in demonstration or reference to authority by citation, as for that basis of sound reason to question and, or, challenge.
The reason so few Astrologers have implemented the use of Astrologicl Parts in natal analyses is the very reason that there are too many websites and people as like the proprietor of "Skyscript", that claim to be some sort of "authority" on astrological knowledge, on the internet and, or, are published, that haven't any real clue as to what most of the Astrological Parts really do influence or how, or why...and won't admit to their inadequacies or budge from their positions.
It's sad really... it's like watching some very aged Hollywood celebrity cling to distant and vague memories of yesteryear's acclaim and fame, that still want to play the same roles at the end of their careers that they played in their youth and foolishly believe that they can..or as like the Vatican denouncing anyone that proposed that anything other than the earth was the center of all ephemeral activity four hundred years ago.
When I was in grade school my second grade teacher told us that the reason that we had winter and summer seasons was factually a matter of when the earth is closer to the Sun in relation as to when it was further at other times... as that was the accepted scientific opinion in her college days. Despite the fact that notion was proved otherwise some years before i ever set foot in a classroom, she either was declaring it so out of defiance and nonacceptance of more recent scientific finds and disclosures as to the otherwise, or for her being ignorant of the more recent developments of the knowledge, since her youth.
