Consider these four poles of influence:
1) Ascendant: the Self.
2) Descendant: the Other(s), the partner or the public who have utterly independent will from my own.
3) Nadir (IC): the Home, the (Earth) Mother, that which nourishes and protects us.
4) Midheaven (MC): the Social Status, Work, the (Heavenly) Father, that which leads us away from home, into the world.
In the 12 division of Houses in a horoscope, these 4 poles exert their influence continuously, often challenging us through the very polarity of their demands. To live a balanced life, we must stand between these four opposite poles, able to go back and forth between them as necessary.
The synthesis idea of “Hemisphere analysis” comes from this:
1) What happens if most or all planets are concentrated on the East (i.e. left side)? This suggests that the psychic resources are pulled together in order to protect the Ascendant, the Self. There may be defensiveness, or constant need for self justification. Why is this so?
To come into balance, there needs to be a flow of psychic energy directed to the West, meaning Other(s) – giving of self to others, and showing/sharing one’s personal resources with the public.
2) If most of the planets are concentrated on the West (right side), great deal of psychic energy is spent on understanding, serving, or giving to others. There is a danger that one’s self may be left behind. To balance this tendency, there needs to be time taken for oneself (Ascendant), to do what one wants and needs to do.
3) If most of the planets are found in Northern (i.e. bottom half of the chart) hemisphere, The psychic resources are tied to home – most often the developmental concerns within early home.
We suspect that there is an unfinished business from early home that may be hindering the full bloom of identity. Here one needs to “leave home”, either figuratively or literally, by breaking out of limiting patterns that were modeled by his/her family.
4) If most of the planets are found in Southern (top half) hemisphere, the psychic resources have been pulled away from the home base, perhaps too soon. There may be no safety net to protect the identity development – we sense a vulnerability to being pushed around by the circumstance, even victimized by it.
To balance this, one needs to find a safe “home base” (back to the IC), people that he/she can trust to create that sanctuary of safety and nourishment. This allows for psychic grounding to occur, and one is less vulnerable to being pushed around by the world.
Noel Tyl talks about the hemisphere analysis in more detail here.