In posts #301 and #302 Antinor01 and elucidator each answered this question, at least for the simplest case, with the answer: “Birthdate, time, location”.
It can also been inferred that discussing with the subject makes for a more fun experience for the astrologer. (Which isn’t surprising, really.) Apparently this also makes the results of the reading more accurate, presumably through a combination of cold reading (conscious or unconscious) and explicitly clarifying the generalities with details supplied by the subject. Of course, this stuff sounds like cheating to me, and not part of the astrology itself as such, which (from the sound of it) is strictly calculable and unvarying based on the aforementioned birthdate, time, and location.
Based on the four readings Czarcasm posted, absolutely not; all four seem to be mixing in various other astrological-ish sources, including in one case astrological palmistry. ( :dubious: ) Also, elicidator has many times mentioned that there is a relatively low amount of agreement amongst the whole of astrologers as a whole about how this stuff is to be done.
(And if that wasn’t enough, wiki lists three different sets of dates for what a (for example) “Taurus” is: Tropical: April 21 - May 21, Sidereal: May 15 - June 16, and Solar: May 14 - June 19. So clearly there are different systems in effect! (Under two of which, I’m not even a taurus like I thought I was, but am instead a whatever-comes-before-a-taurus. Who knew.)
I found the first to be the most analytical, and it seemed to make some rather confirmable predictions, especially if you deliberately ran it for prior dates and checked against your history.
The second was creepy and scary and evil-seeming; I didn’t dwell on it.
The third was corrupted with palmistry, with that mixed in over the top of the ‘normal’ astrology that I couldn’t tell what was what; it did make some fairly specific testable claims however.
And the fourth was like, way trippy and let the flowers sing and crystals chime, man. (And it didn’t seem overly specific, either, though I might just be misunderstanding it, as it was rather incomprehensible to me for some reason.)
I wonder if any of these resemble the kind of stuff the astrologers in this thread are familiar with, if any of them do?