Moon (astrology)

Definition

The Moon in astrology is the luminary nearest the earth and the fastest-moving body in the chart. Ptolemy gave it a moist, softening power and, with Venus, called it feminine and nocturnal. In the modern tradition the Moon's sign and house are read for emotional temperament and the habits a person falls back on.

Primary source

Most of the moon's power consists of humidifying, clearly because it is close to the earth and because of the moist exhalations…

— Ptolemy, Tetrabiblos I.4, Of the Power of the Planets, trans. F. E. Robbins (Loeb Classical Library 435, Harvard University Press, 1940). Open-access copy

Deep Understanding

Ptolemy describes every planet through the four qualities of ancient physics: hot, cold, moist and dry. The Moon is the moist one. He explains its moisture by its nearness to the earth and the vapours rising from it, and he adds that it shares a little of the Sun's heat through the light it borrows. Its action, in his words, is to soften.

The Moon is also the one body whose quality changes visibly within a month. In his chapter on aspects to the Sun, Ptolemy says the waxing Moon from new to first quarter is more productive of moisture, from first quarter to full of heat, from full to last quarter of dryness, and from last quarter to its disappearance of cold. He reports that the ancients counted it, with Jupiter and Venus, among the beneficent planets. He gives it Cancer as its house, and in the chapter on parents he links the Moon and Venus with the mother, as the Sun and Saturn are linked with the father.

In the cosmology of the seven spheres the Moon's is the lowest, the one closest to the earth, and Gnostic readers counted it among the seven planetary rulers of the hebdomad. The two lunar nodes, the North Node and the South Node, are the points where its orbit crosses the Sun's apparent path. The modern tradition reads the natal Moon for the inner, reactive side of a person: what they need, how they seek comfort, and the moods that come and go.

Often confused with

Lunar Principle: the alchemical luna, a receptive quality in matter and in the psyche, where the Moon here is the body in the sky and its place in a chart. North Node: a calculated point on the Moon's orbit, where the Moon is the luminary itself.

In Practice

Keep a month of short evening notes: the Moon's phase, the sign it is in, and one line about the day. Ptolemy tied the phases to changes of quality, and modern astrologers tie the sign to temperament. A month of your own notes lets you set their claims beside what you actually saw.

Stefan's Alkimia. (2026, October 1). Moon (astrology). Pleroma Guide. https://pleroma.guide/en/lexicon/moon

Stefan's Alkimia. “Moon (astrology).” Pleroma Guide, 1 Oct. 2026, pleroma.guide/en/lexicon/moon.

Stefan's Alkimia. “Moon (astrology).” Pleroma Guide. October 1, 2026. https://pleroma.guide/en/lexicon/moon.

@online{alkimia2026moon,
  author = {{Stefan's Alkimia}},
  title = {{Moon (astrology)}},
  organization = {{Pleroma Guide}},
  date = {2026-10-01},
  year = {2026},
  url = {https://pleroma.guide/en/lexicon/moon},
  langid = {english}
}