Astrology seems to be re-emerging in genre fiction after a twenty-year sleep. This is good. What isn't quite so good is that all too often when people hear the word "astrology" they expect the bastardized version of astrology you find on the newspaper comic pages: one that reduces all people to one of twelve archetypes.
This has never been what real astrology does. Though the signs do describe archetypes, each person's chart features ten astrological planets each in its own sign, each placed in one of the twelve astrological houses, all interacting with each other in ways that make some strong, some weak, some keys to the individual's character, and some muted in their effect.
This is why real astrology describes real people, with all the conflicts, contradictions, strengths and weaknesses that real people display.
Let's look briefly at what Sun Sign Astrology might tell us about a person, and then compare it with what real astrology might say.
Sun sign astrology tells us that a person born with the sun in Leo is "proud, regal, theatrical, creative, and may have child-like traits or be heavily invested in his or her children." We all know people like that, but what you've got here is really an archetype not a description of the one twelfth of all humans alive who were born between July 23 and August 23.
Real astrology tells us a lot more about a "Leo" because it looks not only at what sign the Sun was in at birth, but also where the Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto were. Each planet describe a facet of personality and each may be found in a different sign.
The most important factor on a real astrological chart is NOT the sign of the Sun, it's what sign (and degree) was on the horizon at the moment of birth--that of the Ascendant. That is because the position of the Ascendant determines how the chart is divided into Houses. Houses, in turn, determine what area of life a planet (including the Sun) will express in.
A person whose Sun was in Leo might have been born before dawn, which would put their Sun in the First House. Their life would be about self expression and they'd express their creative Leo ego energy in a way that might strike others as selfish. The person with a First House Leo Sun is likely to be a Prima Donna--and that's what they're supposed to be.
Another Leo born the same day just before sunset would have their Sun located in their chart's Seventh house. Their life would be about partnership. They'd still be creative, theatrical, and childlike at heart, but they might well choose a partner to express those traits for them and stand out of the way while the partner does his or her thing. They'd have and Aquarius ascendant if born that time of day, which would make them appear to the world to be a far more objective, political, impersonal kind of person. Only those who knew the person very well would be aware that all three of this person's spouses were dramatic, childlike, creative people and realize how this "Leo" expressed the Leo archetype.
The placement of the planets besides the Sun are vital too.
The Moon moves into a new sign every two and a half days. It describes many things about a person, the most important of which is their early childhood environment, the person's perception of their mother, and what they expect from the world (which is of course conditioned by the early childhood experience.)
A Leo with an energetic, impulsive, perhaps even angry, Aries Moon will have a very different childhood and learn a very different way of interacting with the world than a person would who was born into the environment described by the oversensitive, self-sacrificing, religious or perhaps addicted or dishonest Pisces Moon, though the two individuals might have been born less than three days apart.
Add because these Moons are probably going to be placed n a different House on the chart, the complexities increase. A person with a Pisces Moon in the Tenth House might have mother who was all too well known in their home town for a drinking problem. Another Leo with a Pisces Moon placed in the Second House might have had a childhood dominated by a mother who was unable to manage her finances or who was bilked of them by a con man. These people will have very different core issues which have in common only that they make it difficult to express the creativity and warmth their Leo Sun might give them.
How well the individual's Sun and Moon relate toe each other makes a difference in personality, too. A Leo whose Aries Moon makes a pleasant Trine with that Leo Sun will tend to have parents (also represented by Sun and Moon) who get along and the person will be able to express themselves with ease because nature (Sun) and nurture (Moon) are in harmony.
The Leo with the Pisces Moon has a tougher time. These planets connect in a way that is uncomfortable, so the individual's upbringing with its undertone of confusion, deception, or sacrifice for others, may make it hard for them to feel comfortable expressing themselves in the classic confident Leo manner.
These examples barely scratch the surface, but they give you some idea of why real astrology is a wonderful tool for understanding the rich complexity of real people.
And because complex real people are the characters readers enjoy reading about the most, real astrology can help you add layers of complexity to your characters. Using a real chart will remind you that each person is a complex collection of psychological traits, some of which they express easily, some of which are blocked, and some of which are incompatible with each other.
A real chart can point you to which conflicts are most likely to be the toughest and most rewarding for your characters. Give a character a Sun Sign personality that demands they achieve a certain kind of self-expression but give them other Planets that makes it tough to express that self, and you have the beginnings of an enjoyable novel.
Using real astrology forces you away from archetypes. Your Leo who is a Prince living in a palace is boring. Give him a Capricorn Moon in the Sixth House. Now his parents are defeated by an enemy shortly after his birth and he's raised as a servant. Sprinkle in some Pisces on his chart, so that he's been deceived about who he really is. Then give him a Sagittarius Mars that propels him into a journey that will lead him to the lessons he needs to become what he feels he is inside.
Suddenly you have what looks like an interesting story--one that is character-driven--and one that uses astrology to create characters that have the mix of archetype and complexity that characterize real people.