Astrologers assigned Pluto the significations of transformation, death and rebirth, power, compulsion, the hidden, the buried and the collective unconscious, and commonly gave it the rulership of Scorpio in place of or alongside Mars. Its orbit is long, about two hundred and forty-eight years, and eccentric enough that it spends very different lengths of time in different signs, from about twelve years in Scorpio to over thirty in Taurus. Most astrologers who use it continued to do so after 2006, on the reasonable ground that astrological practice is not bound by the IAU's definitional decisions, which concern nomenclature within astronomy. What the reclassification does establish is a plain matter of fact that any honest account should include: Pluto is a small icy body, smaller than the Moon, and one of many such in the outer solar system. Its astrological meaning, less than a century old, is a modern construction.
The unequal sign durations have a specific cause and a specific consequence. The cause is an orbital eccentricity of about 0.25, which carries Pluto from 29.7 astronomical units at perihelion out to 49.3 at aphelion; it moves fastest through the signs it passes near perihelion and slowest at the far end. The consequence is that a Pluto sign is a generational marker and nothing more personal. Everyone born across a span of twelve to thirty years shares it, so whatever is said of a Pluto placement individually has to come from the house and the aspects. The New Horizons flyby of 14 July 2015 returned the first close images, showing nitrogen ice plains and mountains of water ice on a body that is geologically active despite its size.