In Which I Think More about Astrology and I'm Still Confused

It leaves many unanswered questions, the most pressing (after how anyone could take this seriously) being, what happens when humans leave Earth to colonize other planets?  Or at least build habitable far-flung space stations and develop a huge squabbling conglomerate of Terran inhabited space?  Do the astrologically-inclined still use Terran constellations?  Do they declare (constellations aren't really discovered so much as declared) their own constellations?  Named after whom or what?  I really hope the answer is not movie actors or pop singers.  And how many zodiac signs does each planet need?  What about multiple suns and moons?  What about planets in which there is daylight always and stars are never seen?  Once there is an astrological system developed, how is this reconciled with the astrological systems of other planets?

A simple example:  A young Martian lad is going to Terra for schooling.   Being of an astrological persuasion he knows that he can be described as sun in Asimov, Phobos in le Guin, and Deimos in idbehold.  This means he is bright, adventurous, genetically disposed to a full beard, ideologically inclined to feminism, and primed to expect an infinite supply of power ups from ambient fate with a minimum amount of effort on his part.  As the stereotypical (if discriminated against due to Martian accent) college student he is at a party making amorous advances toward young women of his own social class.  He meets a smashing young lady who reveals that she is a Taurus with moon in Libra.  How does our Martian lad determine if she is a proper romantic pairing using only astrology rather than respectful overtures of conversation to determine what she is like as a person?