In antiquity astronomy and astrology were one and the same and it was a lot more accurate too. It seems some rift some schism has compromised the art and split it into an art and a science. Astronomers think  astrology is some archaic mythology left over from a time when people worshiped gods, and astrologers think astronomy is far to much math to bother with, but one is merely a counterpart to another and both are needed for it to be whole.

I'll explain using sun signs then. There are twelve zodiac signs, that are commonly accepted. These are star formations that have mythology a story and an energy that they embody. Each star formation takes up a certain amount of space in the sky. When the sun falls between earth and a particular sign, then the sun is in that sign. You know how when your traveling there's not like a boarder that cleanly divides one region from the next, it's not like you go through a lush environment and then when you come into the next one suddenly there's a cut off the it's arid desert. It's more gradual, like there is an overlap. It's the same for the sun traveling through signs.

With houses the zodiac is divided into 12 houses each ruling a different energy. A planet in orbit will fall at some degree to any one of the houses. When it is exact is when it is in the center of a house, any where else it is in degrees negative or positive to the house position, and when it is not exact, that is in between then it has less influence. When it is most exact it when it has most influence. So looking at a chart, and an aspect being one thing in position to another from a point of reference, which includes planets in houses and the sun in signs, the aspects that are most exact bear the most relevance.

Again, why do you insist on going 'off topic' this thread is for 'house cusps'

Again you want to discuss approaching/departing mathematical aspects or atronomy??

you said,
"With houses the zodiac is divided into 12 houses each ruling a different energy. A planet in orbit will fall at some degree to any one of the houses. When it is exact is when it is in the center of a house, any where else it is in degrees negative or positive to the house position, and when it is not exact, that is in between then it has less influence. When it is most exact it when it has most influence. So looking at a chart, and an aspect being one thing in position to another from a point of reference, which includes planets in houses and the sun in signs, the aspects that are most exact bear the most relevance."

and the point being?? There are ALL sorts of astrologers too, you sound like a Traditional Astrologer that doesn't even consider the outer planets as being relevent.

Well I'm a modern astrologer that Teaches, Lectures & uses Equal house system

There are about 8-10 popular house systems too, the other mostly widely used, only cos it's the default on astro dot com, is Placidus, which uses unequal size houses

Just to go off topic cos it seems everyone wants to
Solar Arcs
Solar arcs are really simple, especially for beginners, just move the Angles, Asc, Desc, MC, IC 1' for each year of your life onto planets and vice versa. Not just used for rectification either. Under age 12 though these interpretations are directed towards family changes, maybe relocation, job changes, illnesses, additions to family etc.

Rectification of birth time
http://www.youtube.com/watch?v=KW0G2S2Ti4I
http://www.youtube.com/watch?v=OYMX9X2C1BQ&NR=1
• Transiting Pluto square, conj opp Asc, Desc, MC, IC
• If under 12’ when it conj an Angle then their age was under age 12 it’s parents adjustments. A death, change within father’s work, a separation, remarriage.
• Adults or teens, 1st job, identity transformation MC.
• Pluto conj Desc = death, health concerns, geographic, significant relationship or break up, but has to be ‘life transforming’
• Also try transiting Neptune, something dissolving, disappearing, confusing etc.
• Timings of transits… is it the 1st hit? More often it’s the middle retrograde hit… but could be the last direct hit also. 1’ =4minutes in time.

http://www.frankstar.com/solararc.htm
http://thezodiac.com/arcs.htm
http://www.donmc.com/Comparing%20Transits%20and%20Solar%20Arcs%20II.htm
http://en.mimi.hu/astrology/solar_arc_directions.html
http://en.wikipedia.org/wiki/Astrological_progression