The Solar-Lunar Cycle

The phases of the Moon are central to our conception of the celestial body. It’s ever-changing, cyclicly growing and shrinking state has been one of humanity’s longest fascinations. The Moon is a wondrous thing, reflecting the light of the bright Sun in a way that can actually be looked at. For millennia, it was the only source of nocturnal light. Periods where the Moon was dark (around the New Moon) meant that the day effectively stopped at sunset and little could be done effectively in the night. Alternatively, around the Full Moon there was such a capability to see that work could be done long into the night, parties could be had, and performances held under the lunar spotlight.

The phases were noted for other influences too including the cycles of hormonal change, the bleeding of certain bodies, the growth of plants, the motion of the tides, and many other physical factors. Each month, the Moon plays out a small version of the entire solar cycle through the Zodiac, reflecting the Sun’s light wherever it currently is. Because the Sun continues to move as the Moon does, completing a cycle with the Sun takes a little longer than returning to a single location in the sky.

The Moon’s cycle with the Sun is about approximately 29.5 days long (or 29 days 12 hours 45 minutes give or take a few). During the Moon’s journey through the stars, the Sun’s average motion takes it almost an entire zodiac sign. This results in consecutive New Moons typically taking place in consecutive zodiac signs (with an occasional repeat). This lunar phase cycle ties together the two “lights” in the sky, keeping them connected even when they are apart.

Waxing and Waning

Astrologers have been defining the size of the lunar phases for centuries. At the most basic level, there are two phases: waxing and waning. The waxing phase involves a growing Moon, the sliver of light on the right hand side, heading toward Full. At this stage, the Moon appears in the evening sky after sunset, illuminating the night with an increasing light. After the Full Moon, it wanes and decrease back to New. In this period, the sliver of reflected light is on the left and the Moon rises before the Sun in the morning sky. Steven Forrest also draws a lunar binary between the bright Moon (the half centered on Full) and the dark Moon (the half centered on New). Out of these two divisions of the cycle, the four lunar Quadrants easily emerge.

In traditional astrology, the waxing phase is associated with growth, increase, production, and potentials. The waning phase is associated with loss, decrease, inaction, and death. This often had natural and material implications attached to it and was not always greatly utilized in the interpretation of birth charts. At the most, a waxing moon may have been able to offset and mitigate some difficult situations that a waning moon was said to not resist. Lunar phase was also partially utilized in certain techniques to determine powerful positions in the chart. However, several authors also focused on smaller phase divisions, like those in the following,

Lunar Quadrants

The Quadrants of the Moon have been historically related to the four seasons of the solar journey and assigned qualities to describe their nature as described by Ptolemy and Porphyry. Spring corresponds to the 1st Quadrant (0-90º), Summer to the 2nd (90-180º), Fall to the 3rd (180-270º), and Winter to the 4th (270-360º). In each quadrant, the Moon increasingly grows into a particular quality (hot, cold, wet, dry) that describes its current expression. This is especially helpful in the system of Arabic astrologers like Abū Ma’shar, who sought to define all of the physical changes that could occur to the nature of a planet. The Moon inherently acts a certain way, but in this framework the Quadrants describe subtle changes to its qualities and nature through its relationship to the Sun.

Ptolemy assigns the wet quality to the 1st Quadrant. Moisture creates humidity which results in the hot 2nd Quadrant. Heat dries out, leaving the 3rd Quadrant to have the dry quality. This leads to a cool down and cold completely the 4th Quadrant. Cold draws out moisture, which restarts the process again. This system of flow and exchange is a central part of Aristotelian natural physics, ties together the entire lunar cycle into a repeating process of flow and interchange. In Abū Ma’shar, one quality per Quadrant became two in order to better represent the process of coming to be and going away that was described in natural physics.

The quadrants are described in a more psycho-spiritual framework by the early 20th century astrologer Dane Rudhyar and later by Steven Forrest (among others). In this system, each quadrant describes an internal orientation toward life and the world. The 1st is described as “subjective, unconscious, idealizing” and the Second “maturing, engaged, and seeking interaction” as the Moon heads toward its Full phase. After this, the 3rd Quadrant “shares knowledge, accepts or resists the past” while the Fourth “prepares for ending and release, making momentary meaning.”

When speaking about the qualities assigned to each lunar quadrant, Ptolemy uses an adjective phrase meaning “increasingly”. According to Rob Hand’s commentary, Ptolemy means that the Moon grows in its indication throughout the quadrant. So instead of picturing the entire 1st Quadrant as wet, it is “increasingly more productive of moisture.” At the New Moon, there is not much moisture yet, but by the time the Moon is nearing 90º of separation, it has become quite wet. This same principle can be applied to the modern view of the lunar quadrants. Instead of seeing the entire quadrant as embodying a singular internal state, there can be a handing over of one state to the next. So the subjective idealism of the 1st Quadrant grows into the engaged interaction of the 2nd and so on.


Many different astrologers across history have defined different lunar phases. The 8-phase model that is so popular today was popularized by Dane Rudhyar in the early 20th century. It divides each quadrant in half, yielding eight 45º sections. Interestingly, a very similar phase cycle exists in early Hellenistic astrologers like Vettius Valens. He names the same degree separations for phases, but adds a few extra phases to deal with the visibility of the Moon when near the Sun.

For Rudhyar, the 8 phases represent developmental processes. He uses analogies both of plant growth and pregnancy at different times to describe the growing of the waxing phases, reaching towards life and the sharing and spreading of the waning phases. It is less a system of identifying distinct visual phases and ore of a way to describe certain lunar states of being. The states are then linked with personality types and ways of being.

Being concerned with more than just personality description, the older phase models tend to be more physical description of the lunar phases. Valens adds “first rising” when the Moon is 15º separated from the Sun and just becoming visible in the evening sky as well as “setting” when the Moon has disappeared under that 15º range but not yet caught the Sun and been New. Each further emphasizes the liminal nature of the New Moon, identifying differences between when the Moon can still be seen and when an entire night is spent in the dark. He also describes a “first waning” to differentiate between what is truly a “full” moon at 180º from the Sun and the beginning of its loss of light.

Similar descriptions come from other Hellenistic authors, although occasionally with different degree values for the phases. For instance, Paulus and Porphyry both say crescent and gibbous moons start at 60º and 120º from the Sun on each side (waxing gibbous at 110º for Porphyry). This places the phase change at the same place as an aspect, a sextile or a trine. In a similar fashion, Firmicus tells his reader to pay attention to the Moon’s aspects, only mentioning phase names in passing without degrees attached to them.

Centuries later, Abū Ma’shar laid out a 16-phase cycle of the Moon in his Great Introduction. Interestingly, it keeps the same basic phase division found in Valens and recreated by Rudhyar. Divisions are given at 45º and 135º for crescent and gibbous, not at the aspect values. However, the 16 phases come from a detailed description of the Moon conjunct and opposite the Sun. It takes into account many different theoretical concepts like “bonding”, “under the beams”, “combustion”, and “cazimi”. The version of the phases captures everything, but likely isn’t helpful for understanding how lunar phase works in birth charts. However, it is extremely useful for understanding the technical state of the Moon in relationship to the Sun.

In my practice, I tend to utilize Valens’ phase divisions in league with the general Rudhyar approach. It is immensely helpful to differentiate between the visible and invisible Moon around the conjunction and it offers more nuance than the purely numerical phase divisions. This way, New and Full Moon’s can be treated as singular experiences and the rest of the soli-lunar relationships can be described adequately through the phases. However, the aspect approach is also worthwhile, as aspects are important descriptors of interplanetary relationship. Play around with exactly where you draw the line for crescent and gibbous moons. Know that the Moon is not an exact being and so any strict definitions are likely to fail at times. Keep an open mind and experiment with different phase models.

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