If you are so far into astrology that you know which sign and house your planets occupy and the exact degree of all these, plus your descendant, Midheaven, Immum Coeli and more, you might like to work out the decans and dwaads of all these and see what they tell you. Checking charts for compatibility between two people is another obvious matter when it comes to decans and dwaads.
The Midheaven will show where a person's aims and ambitions lie and what they want to make of life. This neglected area of astrology should also be studied for the effect it has on the psychology of a person, because this can show what they are really striving for. Differences in the Midheaven dwaad typically account for the different behavior and nature between even the closest of twins, which shows just how important this is. Many people make happy relationships and partnerships with those whose Sun is in the same sign as their Midheaven, and the decan or dwaad will also have a bearing on this.
The descendant shows the kind of outlook and behavior that a person seeks from those whom he chooses to like or to love. It doesn't mean that a person should marry a person whose Sun or ascendant is in the same sign as their descendant, only that they should share the values that it encompasses. Study the descendant position in full to see what it is that a person is looking for in others.
The lmum Coeli shows the kind of background a person came from and also the kind of home and family life they would like to have. It can refer to the circumstances of the beginning and early days of a person's life, and according to tradition, this also shows the circumstances at the end of life.
The word synastry comes from the Latin word sinister. This doesn't mean that Dracula is about to jump out of your closet, it is simply the word for left in the same way that dexter means right. In astrology, this usually refers to a lover, possibly a good friend or a business partner; thus what we are referring to here is the compatibility between two people's horoscope charts. For this, you can include the positions of the Sun, Moon, ascendant, descendant, Mars, Venus and anything else that you would like to study. If a relationship between two people is particularly good while on the face of things, their charts are not particularly compatible. In this case, take a look at the decans and dwaads as they may show a truer picture.
Sometimes looking at the decan of just one planet can tell you a great deal about the way it operates. For instance, someone with Mars or Venus in Sagittarius may be prone to chase the opposite sex if in the Sagittarius or Aries decan, but is far less likely to do so when in the Leo decan. Always consider the planet that rules the decan or dwaad in question. For instance, a Venus ruled dwaad will act in a different way from a Jupiter ruled one.
The sign, house, decan and dwaad of the part of fortune can tell you how you will make your way in life and how you can expect to make money or make your way in the world.
Many people find themselves attracted to a particular type of person, sometimes in a fated or an obsessive manner, or they may find that a particular star sign turns up among their relatives, friends and lovers whether they look for this or not. Whatever the scene, study the sign, house, decan and dwaad of the vertex to discover what is going on.
Absolutely anything that you choose to look into that appears on a horoscope will have its relevant decan and dwaad, so you can apply this to asteroids, midpoints and anything else that you fancy investigating. Try taking a look at the Black Moon, because this is a particularly destructive force on a horoscope.