I am doing what I call and astrological background on a friend and I am amazed at how simular the contexts are given the stationary and moving bodies you cant help but wonder what force drove people all over the world to think so much alike

PLANETARY ASPECTS-east & west, a comparative view.
All systems of astrology acknowledge aspects, which exist between the planets in the chart. Aspects means, acquired influence, projected by the planets to certain points from the given position in the zodiac. In Western astrology, these aspects are carefully calculated considering the exact degrees, between planets.V edic astrology,judges aspects relative to sign.A planet aspects sign as a whole.Vedic astrology distinguished aspects only by their strength as major or minor & does not ascribe any particular quality to different aspects. Western astrology ascribes a different nature to different aspects.Some aspects like square tend to be malefic others tend to be benefic.

Basic astrology
Now basically your sun sign is your 'core beliefs, values, ego' and Asc is your physical body, mode of expression and mask and persona that we all wear and hide behind, but definitely not what's going on underneath. What's going on underneath is your Sun sign. Moon sign, house placements and aspects describe your emotional and intuitive responses, also describes your view of your mother, as saturn describes your father by sign and house position.

So, think of a glass milk bottle the bottle is your Asc and your sun the milk, but the milk still has to 'come out' through the glass neck of the milk bottle....

Now aspects within a natal chart represent 'facets' of our personality, because we are all multifaceted beings. What these do is 'break down and compartmentalise' these facets into smaller bite size chunks. This does take quite a lot of self analysis and objectivity to 'see yourself' and why you do certain things and behave in certain ways. Actually it can be quite good therapy...

Your natal chart is like a photograph as unique as your fingerprint, BUT the 10planets in the sky have not stayed where they were in your natal chart, they have all moved. Predictive astrology is mostly maths where those 10planets are now and the mathematical aspects they make to your natal charts ie: 180'=opposition, 90'=square, 60'=sextile and 120'=trine.

So your personality, grows, develops, changes, matures as we get older, this is reflected by your sun sign changing from it's natal position to the next sign along, so does your Asc and MC sign change. In fact from sun to mars espec are important, as the outer planets really don't move much, using a 'day for a year' secondary progressions.

If you want to research more into Secondary progressions try here
http://cafeastrology.com/secondaryprogressions.html
http://en.wikipedia.org/wiki/Astrological_progression
http://www.aquamoonlight.co.uk/progressions.html
http://www.astrologyweekly.com/forum/forumdisplay.php?f=67

Most of the western astrologers today used the Tropical zodiac for astrological purposes.Tropical zodiac is not based directly on the stars, but on the equinoxes.The first degree of Aries of the tropical zodiac ,is identical with the point of the vernal equinox,the place of Sun at the first degree of spring. It does not start with any specific group of stars.
Vedic astrology uses the zodiac which corresponds to the actual constellations or the fixed stars.It is called as Sidereal Zodiac
Thus two different methods of determining the signs of the zodiac exist,based on the different kind of calculation. Neither is necessarily wrong.