Meaning
Clyde Tombaugh found Pluto at the Lowell Observatory on 18 February 1930, and the discovery was announced on 13 March. In 2006 the International Astronomical Union reclassified it as a dwarf planet; astrologers kept it, as they keep Chiron.
Its orbit takes 247.9 years and is so eccentric that it spends between about twelve and thirty years in a sign, so its sign marks a generation and its house and aspects carry the personal reading.
Modern astrology reads Pluto as depth, power, endings and renewal. Our keywords are "power, depth, transformation".
A ruler within a decade
Astrologers had listed Pluto as ruler of Scorpio by 1936, though some argued for Aries into the 1940s. The traditional revival keeps Mars. We name Mars as Scorpio's ruler and Pluto as its modern co-ruler, second.
Glyph and correspondences
Two glyphs are in use: the PL monogram, ♇, for Percival Lowell, and the bident with an orb, the trident's two-pronged cousin drawn in the figure on this page. We draw the bident, by the owner's choice of 2026. Paul Foster Case in 1933 set Pluto beside Judgement, with his own question mark; the Golden Dawn's Book T gives that trump the element of fire.
In our readings
Our chart's own line for Pluto reads: "Pluto represents depth, power, letting go and the capacity for profound renewal." The chart gives Pluto a reading in each sign and house like any planet. Its sign is shared by everyone born over twelve to thirty years, so the house and the aspects carry the personal reading. As chart ruler it gets a line of its own: "With Pluto as the modern ruler of Scorpio rising, depth, intensity and cycles of renewal tend to run through the whole life." These are EsoTerrier's words, written in 2026.
Correspondences
Each item with how it stands: “sourced” is in the work cited, “our construction” is EsoTerrier’s own, and “disputed” means the sources disagree.
- Discovery
- 18 February 1930, Clyde Tombaugh, Lowell Observatory (announced 13 March 1930) sourced
- Ruler of Scorpio
- Listed as ruler of Scorpio by 1936, with Aries still argued in the 1940s disputed
- Trump (Paul Foster Case, 1933)
- Judgement (Case writes 'Pluto(?)'); not in Book T sourced
- A generation's sign
- Twelve to thirty years in a sign, so its sign is shared across a generation sourced
- Our keywords
- "power, depth, transformation" our construction
How the schools read it
- Modern Western
- Co-ruler of Scorpio; read for its house and aspects, its sign as a generation's.
- Traditional revival (Project Hindsight and after)
- Not used as a ruler; sometimes not shown.
- Jyotisha
- Shown only behind a "modern planets" switch in some Indian tools.
- EsoTerrier
- Shown on the wheel; named second as co-ruler of Scorpio; keywords "power, depth, transformation".
Claims about it
-
Uranus, Neptune and Pluto rule Aquarius, Pisces and Scorpio.
disputedWhat the record shows: A modern attribution made in stages after the three discoveries; the traditional rulers are Saturn, Jupiter and Mars, and the traditional revival keeps them. We name the traditional ruler first and the modern co-ruler beside it.
