Moon Phases

What is a moon phase in astrology?

A moon phase is the stage of the lunar cycle shown by how much of the Moon’s sunlit side faces the Earth, which depends on the angle between the Moon and the Sun. As the Moon orbits the Earth, that angle grows from 0° to 360° in about 29.5 days, the synodic month, and the lit part grows and shrinks with it. Every phase is therefore also an aspect: the new moon is a Sun–Moon conjunction, the quarters are squares, the full moon an opposition.

The familiar eight-phase astronomical sequence combines four exact moments with the crescent and gibbous intervals between them. These are the appearances listed below; Rudhyar’s eight equal astrological intervals are a separate way of dividing the same cycle:

Phase	Moon ahead of the Sun	When you can see it
New moon	0°	not visible; it rises and sets with the Sun
Waxing crescent	between 0° and 90°	low in the west after sunset
First quarter	90°	high in the evening sky, half lit
Waxing gibbous	between 90° and 180°	from afternoon into the night
Full moon	180°	rises at sunset, sets at sunrise
Waning gibbous	between 180° and 270°	rises in the late evening
Last quarter	270°	rises around midnight, half lit
Waning crescent	between 270° and 360°	low in the east before sunrise

The moon phase is not the moon sign. The sign tells you where the Moon is in the zodiac; the phase tells you where it is in its conversation with the Sun. A waxing crescent in Aries and a waxing crescent in Libra share a rhythm, while their signs give them different tones.

Where the moon phases come from

People have tracked the Moon’s changing face for as long as they have counted time. The English word “month” comes from the same root as “moon”, and many calendars still follow the cycle: the Islamic calendar is purely lunar, with months that begin when the new crescent is first seen, while the Hebrew and Chinese calendars combine lunar months with the solar year.

Astrologers of antiquity used the phases in practical ways, for example by judging whether the Moon was waxing or waning when a matter began. A waxing Moon, growing in light, was linked with increase; a waning Moon with decrease and completion.

In the twentieth century, Dane Rudhyar’s book The Lunation Cycle (1967) turned the phase into a part of the birth chart. He divided the cycle into eight 45° segments, with names such as “disseminating” and “balsamic” for the later stages, and read the phase of birth as a key to a person’s basic orientation. Modern lunar calendars, with their new-moon intentions and full-moon reviews, grew from this tradition.

How to work with moon phases

Find your birth phase. Measure how far the Moon stood ahead of the Sun at your birth, counting forward through the zodiac. Under 180° you were born in the waxing half of the cycle; over 180°, in the waning half. Waxing-born people are often described as builders and starters, waning-born ones as people who refine, share and complete.

Read the phase together with the signs. A full moon with the Sun in Taurus and the Moon in Scorpio pulls on the axis of security and intimacy; a full moon in Leo and Aquarius on the axis of self and group. The phase gives the rhythm, the signs give the subject.

Use the monthly cycle as a frame. Many people set an intention at the new moon, act on it at the first quarter, see what has become visible at the full moon and let go of what has not worked at the last quarter. It is a way of reflecting in step with a natural rhythm, not a rule that something must happen on a given date.

Read the phase as a theme. Full moon symbolism concerns culmination, visibility and opposition; new moon symbolism concerns conjunction and the start of a cycle. Use those distinctions to frame a question about your current circumstances, alongside the signs and the natal chart.

The Moon Calendar in the Larisa app calculates the current phase and how many days into the cycle the Moon is, together with the next intention window, which makes it easy to follow this rhythm month by month.

Moon phases in four examples

Born at the new moon. The Sun and Moon at 14° Gemini bring conscious identity and emotional needs into conjunction. Gemini gives both a language of curiosity, ideas and exchange. Ask how the person distinguishes what they want to express from what they need to feel secure within the same conversation.

Born at the full moon. The Sun in Sagittarius and the Moon in Gemini, exactly opposite. Set Sagittarius’s search for meaning and conviction beside Gemini’s curiosity and exchange of ideas. In a relationship question, ask how a stated belief meets the need to hear another view; read the opposition through that contrast.

A month followed with the phases. Someone starts a writing project at a new moon in Virgo, reaches the first real obstacle at the first quarter, shares a draft at the full moon and cuts what isn’t working at the last quarter. The phases did not decide the outcome; they gave the month a shape.

Born in the waning crescent. With the Moon 330° ahead of the Sun, just before the new moon, the birth falls at the end of the cycle. Rudhyar called this phase balsamic and read it as one of completion and preparation. Such people may feel older than their age, or drawn to finishing what others began.