(If you haven't read Parts One and Two yet, you'd better go back and have a look at them now.)
Finally, with our Cruise Ship analogy, let's have a look at that cloud of diffuse smoke we're leaving behind as we pull out of port. These are what are called the "minor" aspects.
There are lots of minor aspects, which all come from dividing the circle into ever-smaller pieces, and the more you divide the circle up, the less effect those aspects have. For example, the semi-square and the sesquiquadrate (think of them as the "half a square" and "the square and a half"). They have roughly the same effect as a square, but are much less pronounced and less troublesome. Any proper square will have a much more obvious observable effect on your personality, but these two can show up as minor annoyances. Basically, if you understand everything we've covered so far, you know what you need to know.
Two of the minor aspects stick out a bit more as far as their importance and usefulness, though: the quintile (one-fifth of a circle, or 72 degrees) and the septile (one-seventh of a circle). The quintile represents a relationship between two planets that takes effort to bring out, but once you do it reveals you have a talent for it. You can also have a bi-quintile (144 degrees of separation) which acts the same way. A quintile is kind of like that guy you know who can write reasonably well, and is always talking about that great novel he wants to write... but he never seems to get any further with it than talking about it.
The septile has a lot to do with fate, destiny, and the deeper meaning of life. This would make them a gold mine of astrological spirituality if it weren't for the fact that every other aspect out there is a lot louder and more demanding, and the septiles are hard to define in hard-and-fast terms anyway. If you based an entire astrology consultation on septiles, there would be a lot of hand-waving and talk about Karma, but nothing of actual practical use coming out of the meeting. If you see a lot of septiles in someone's birth chart without a lot of other stuff going on, you may be dealing with someone who would rather chant, pray, and cast a spell to win the lottery than go out and actually get a job in order to make money, for example.
So, although sometimes interesting, for the most part every aspect not mentioned in Part One and Two can be safely ignored. There are also noviles, vigintiles, quattuorvigintiles, undeciles, semi-deciles, quindeciles, and a horde of other really minor aspects... and more than one astrologer has referred to them all as "The Futiles." To be honest with you... professional astrologers don't really need to worry about them, so you probably shouldn't either. And besides, this is an astrology dating site, not a Depth Psychology clinic. Let's figure out if someone is worth a first date before we start analyzing them to death, shall we...?
Now that we know that the aspects affect how planets communicate their energies to each other, and that the type of aspect affects the nature of what's being said... how does this all work out in practical terms?
You probably already know that each planet in your birth chart "rules" a number of things in your life. For example: Mercury "rules" communication, your thought processes, your nervous system, how you speak, your siblings, and so on. Mars "rules" aggression, the sex drive, ambition, how hard you work, your blood pressure, how well you handle knives and machinery, and other things. Further: the nature of each of these functions is affected by the Sign that the planet is in -- Mars in Capricorn may be harder working, more focused, and more efficient than, say Mars in Gemini... but Mars in Gemini may be more imaginative in its efforts, or may be more likely to divide its efforts into two or more projects at once.
The nature of how each planet works is also very strongly affected by the type of aspects it receives from other planets, and what planet(s) it gets aspected by. Next time, in the conclusion to this series, we're going to hook Mercury and Mars up with different aspects and see how it affects how they do their jobs.