Neptune

Definition

Neptune in astrology is the eighth planet from the Sun, found at Berlin in 1846 from Le Verrier's calculations and unknown to every ancient astrologer. Modern astrologers tie it to feeling, dreams, mysticism and dissolution, and to Pisces, a sign Ptolemy had given to Jupiter. Alan Leo's The Art of Synthesis called it the Mystic.

Primary source

The nature of Neptune is at present little understood. … The statements made must, however, be read as opinions and not as definite knowledge.

— Alan Leo, The Art of Synthesis (Astrology for All, vol. IV), ch. XII, Neptune, the Mystic, p. 103 (London: Modern Astrology Office, 3rd ed., revised, 1912). Open-access copy

Deep Understanding

Neptune was the first planet found by calculation rather than by searching the sky. Urbain Le Verrier worked out its position from irregularities in the orbit of Uranus, and Johann Galle found it at the Berlin Observatory on 23 September 1846, within about a degree of the prediction. For the second time in sixty-five years, astrologers had a body that no ancient text described. Its meaning was built from the myth of the sea god and from the charts of people born with it prominent.

The Art of Synthesis, the fourth volume of Leo's Astrology for All series, is frank about how new that meaning was. Its chapter on Neptune opens by calling the planet's nature little understood, explains that the chapter gathers notes by several students who had studied it closely, and asks that they be read as opinion. Those notes make Neptune the planet of Chaos, of a state without shape or definite form, with less direct influence on the physical plane than any other planet; its sphere, they say, lies mainly in the psychic or emotional plane. They also give it two sides: to most people chaos and confusion, to a few a planet of pure love, friendship and wisdom. In every horoscope, the chapter holds, Neptune stands for a nebulous stage everyone passes through, in the gap of memory between sleeping and waking and between one life and the next: the part of each of us not yet brought from chaos into cosmos.

Leo's chapter on Uranus, just before it, pairs the two as the planets discovered in modern times and argues that astrological experience was to some extent bearing out their mythological names. Neptune, god of the watery element, shows a sympathy with water and with the part of human nature held to correspond to it, the feelings and emotions. He also reports that some astrologers believed Neptune the real ruler of Pisces, the night sign of Jupiter. Modern astrology adopted that rulership and reads Neptune for imagination, idealism, mysticism and the blurring of boundaries. Neptune takes about 165 years to circle the zodiac, some fourteen years in each sign on average, so its sign is shared by a generation, and in transit astrology its contacts with a natal chart last months or years.

Often confused with

Uranus: the other planet of the modern era, found by telescope in 1781, which Leo paired with Neptune; astrologers read Uranus for sudden change and the Will, Neptune for feeling, dreams and dissolution.

In Practice

The chapter's own caution is the useful one: its statements are opinions, not definite knowledge. Its notes read Neptune by house rather than by sign, saying that in an angle it touches a person's actions, in a succedent house the feelings and in a cadent house the mind. Everyone born within the same fourteen or so years shares Neptune's sign, so before reading anything personal into Neptune in Sagittarius or Neptune in Capricorn, look at its house and its aspects, which are what differ between two people born in the same year.

Stefan's Alkimia. (2026, September 30). Neptune. Pleroma Guide. https://pleroma.guide/en/lexicon/neptune

Stefan's Alkimia. “Neptune.” Pleroma Guide, 30 Sept. 2026, pleroma.guide/en/lexicon/neptune.

Stefan's Alkimia. “Neptune.” Pleroma Guide. September 30, 2026. https://pleroma.guide/en/lexicon/neptune.

@online{alkimia2026neptune,
  author = {{Stefan's Alkimia}},
  title = {{Neptune}},
  organization = {{Pleroma Guide}},
  date = {2026-09-30},
  year = {2026},
  url = {https://pleroma.guide/en/lexicon/neptune},
  langid = {english}
}