When we talk Astrology, we generally are referring to signs, planets and houses and how they relate in the birth chart. Not every point in the chart, however, has a physical object associated with it. For instance, the most important point on the chart is the ascendant, which is nothing more than the point rising on the eastern horizon at the time of birth. The Lunar nodes are like the ascendant: mathematical points in the sky that represent the lunar and solar eclipse points. They act like a compass, each being exactly one hundred and eighty degrees from each other. Perpertaully retrograde, they move counter clockwise around the chart, unfolding our Karma.
The north node of the moon is called Rahu and the south node is called Ketu. In Vedic mythology, the demon Rahu tricked the god Bhrama, standing in line to drink the nectar of the gods, Soma. Just as the demon was about to take a drink, Bhrama took the Sun and cut the demon in half, separating the head from the body. The head got a taste of Soma, but never got to experience it's results because it was separated from the body before it could swallow, so Rahu represents a constant hunger that can never be satisfied. Ketu, the south node, represents the body of the demon. It works thought detachment and cuts us off from out material existence to appreciate spirituality. Wherever Rahu is placed in the chart, we have an intense passion and tend to be pulled toward this direction in our lives, Wherever Ketu is place represents where our past life Karma has been accrued. We tend to go to that place because it feels natural to us, like returning to your bed after a long trip away from home.
The Lunar nodes change signs about every year and a half. In 2017, Rahu will move into the sign of Cancer and Ketu will move into the sign of Capricorn. When the nodes change signs, it signals a change of direction in our lives, depending on the houses that are impacted. For instance, if your ascendant is located in the sign of Capricorn, Ketu will be moving into the first house and Rahu will be moving into the seventh house. Each house of the zodiac exists with it's opposite located 180 degrees from itself, which represents an axis related to the subject matter of the houses. In this example, the first house represents our-self and the 7th house represent how we relate to other people. For a year and a half, relationships tend to be the main focus of our lives, especially of you are in a Rahu or Ketu dasha.
As a general rule, the house placement of a planet is more important than the sign placement. This is because the house placement is dependent on the placement of the Sun, Moon or the Ascendant, whereas a planet will be in the same sign for everyone born on that day. When I do a consultation, I like to look at the positions of the nodes to get an idea of your passions and areas of comfort. For instance, a person with Rahu in the 10th will put passion into work, which would cause difficulties at home with Ketu in the forth. When we read our charts, we want to keep in mind that the ascendant represents the body, the Moon is our mind and how we feel about things and the Sun is our sense of self. Using the above example, the person could have the Rahu in the 10th from the ascendant and have a passion for work. If it was in the 12th house from the moon, the person would FEEL like they were losing a of jobs and feel restless at work. If this transit was in the same house of the Sun, they would get a huge ego boost from the transit.