The Moon reflects the subconscious, emotional and fluctuating side of the personality. The Moon is considered the ruler of Cancer, and its natural house is the fourth house. In the astrological chart, the Moon is considered a personal planet, reflecting basic psychological functions within the personality.
The Moon is the only natural satellite and nearest body to the earth. From our position, the Moon's observable size equals the observable size of the Sun. As such, it can be contended that the Moon's influence in the personality is as potent, if not more so, as observed in the natural phenomenon of solar eclipse. In this way, its situation in the astrological chart can be crucial in the reflection of a healthy and balanced personality.
Although for simplicity's sake, the Moon in considered a planet in astrology, it is of course not really a planet, but a satellite. Even so, it is considered one of the most important elements in the astrological chart.
The Moon is personal in that it mostly deals with private matters and is not open to public issues. It deals with its own matters, is self-experiencing and is rather accepting of its qualities. Not only that, but it is regulatory in the sense that other planets are guided by its light.
The Moon is considered the baggage of the personality, emotional impressions that have settled deeply. It reflects the darker, unconscious side of the personality, qualities that can sometimes even be renounced by the conscious, "sunny" side. Its expression is often so "automatic" that the person, being so build into that compartment, may be completely blind to the patterns, often getting only a taste of the superficial consequences.
It shows emotional drives which are difficult to explain. It is also the emphatic side of the personality, the maternal and protective instincts. Likewise, it reflects the most fundamental needs of the personality, which may be more unconscious than conscious, and may not be apparent at first sight. It is reflective of the person's loyalty, especially towards its natural affiliations: family, culture and past.
The location of the moon in the houses reflects what is our home base, where do we really come from. Although it is placed in the house after the house of the Sun, where the personality begins forming, and it has as much emotional significance for the individual.
It is the house of the home, and it is the place where we go to rewind and refill our emotional batteries. It is our refuge and where we go when life gets rough. Naturally, when balanced, the individual leaves this place and focuses on the house of the Sun. Returning to this place can sometimes even feel nostalgic.
It indicates areas where we feel emotionally compelled to delve, especially in times when our emotions are higher. It shows where we keep returning, what we are intricately, emotionally involved with. The Moon shows where we go and what we do when we are in our emotive mode. Furthermore, it is the back flavor of everything that we do.
In non-natal charts (return charts, progressions...) a prominent Moon reflects a period of a heightened emotional state. There are often worries that cause this, especially worries about the family or some important family member. There may be a need to take care or help each other.
Alternatively, there may be other emotional issues and difficult moods that cause pain and introversion. There may also be some failures, or other problems that are responsible for this. Even the conjunctions to the Moon will usually reflect some problematic manifestation.