Moon Phase at Birth

What the Moon phase at birth describes

Every month the Moon passes the Sun, pulls away, faces it across the sky and returns. The cycle takes about twenty-nine and a half days from one New Moon to the next, and you were born somewhere along it. Sign and house tell you about the Sun and Moon one at a time. The phase describes them as a relationship: how far your emotional life has travelled from your purpose, and in which direction it is moving.

Astrologers have watched the lunar cycle for as long as there has been astrology, but the eight birth phases used here come from Dane Rudhyar, who set them out in The Lunation Cycle in 1967. Rudhyar treated the Sun as the purpose of a life and the Moon as the means by which that purpose takes shape in the world. At the New Moon a new impulse is planted. By the Full Moon it has become visible, something that can be seen from outside. In the waning half it is shared, questioned and finally released, leaving room for the next seed.

A phase is a temperament, not a fate. Two people born in the Gibbous phase can have charts that differ in almost every other respect, but they tend to share an attitude: here, a habit of refining and improving, a sense that something is nearly ready. The phase pages describe that attitude, how it shows in love and at work, where it goes wrong and how to work with it.

How to find your phase

Take your Moon's position and subtract your Sun's, counting forward through the zodiac. If the Sun is at 10° Taurus (40° from the start of Aries) and the Moon at 20° Leo (140°), the Moon is 100° ahead of the Sun. If the result is negative, add 360°. Then look up the range:

The example's 100° falls in the First Quarter phase. Each phase lasts a little under four days on average, though the Moon's speed varies, so some phases run shorter or longer.

Two points catch people out. First, Rudhyar's phases begin at the exact aspect, not at the moment the sky looks a certain way. A person born a few hours before the exact Full Moon belongs to the Gibbous phase, even though the Moon looked full that night. Second, the phase is not the same as the Sun–Moon aspect. A Moon 100° ahead is past the square and not yet trine, and an orb-based aspect reading would treat it differently.

You can also estimate the phase from signs alone. Count the signs from your Sun to your Moon: the same sign means New or Balsamic, the opposite sign means Gibbous or Full, and every Sun and Moon combination page names the two phases its signs allow.

Waxing and waning births

The first four phases belong to the waxing Moon, the light growing from a sliver to full. Rudhyar read these as phases of building: the impulse is still being turned into a form, and people born here tend to learn by doing, to look forward and to measure themselves by what they make. The New Moon person acts on instinct; the Crescent pushes against the pull of old habits; the First Quarter meets resistance and decides; the Gibbous studies and perfects.

The last four belong to the waning Moon, the light shrinking back toward dark. These are phases of meaning: what has been built is now understood, shared or questioned. The Full Moon person sees things in relation to others; the Disseminating person passes on what has been learned; the Last Quarter turns inward and revises beliefs; the Balsamic lets go and prepares for what comes next.

The split is not a ranking. Waxing births are not younger souls and waning births are not wiser ones. The difference is orientation: toward forming something, or toward understanding what has been formed. Many people find they lean on the opposite half of the cycle at different points in life, and the phase pages suggest practices for each.

Rudhyar also paid attention to the lunation before birth: the sign and house of the last New Moon before you were born, which he read as a seed for the whole life. That is a separate technique and these pages do not cover it.

Using the phase with the rest of the chart

Read the phase after your Sun and Moon signs, not instead of them. A Full Moon phase birth always puts the lights in opposite or nearly opposite signs, so the phase page and the Sun–Moon page describe the same tension from two angles. A New Moon birth usually puts both lights in one sign, and the Sun–Moon page then describes a single concentrated temperament.

The houses of the Sun and Moon show where the phase is lived. A First Quarter birth with the Sun in the tenth house and the Moon in the first faces its crises of action in career and self-assertion; the same phase with the lights in the fourth and seventh plays out at home and in partnership.

The Moon's speed at birth, its sign and its aspects to other planets still matter. The phase describes the shape of the Sun–Moon relationship; the rest of the chart fills in what that relationship is made of.

If your Moon sits within a degree or two of a phase boundary, read both pages. A birth at 44° sits at the end of the New Moon phase with the Crescent close behind, and many people born on a boundary recognise something of each. The birth time decides the exact figure, because the Moon moves about half a degree an hour.