In their day during the late 20th Century, the Centaur planetary bodies were the cutting edge of astrology. Located in elliptical orbits between Saturn and Uranus for the most part, these small icy planetoids were the enigmatic precursors to what later became the flood of new planet discoveries in the early 21st Century.
From the late 1970s to the end of the century, dozens and dozens of small new minor planetary bodies were discovered as observational technology grew more sophisticated. Many of these newly-discovered bodies are little more than over-grown snowballs of little interest to anyone but astronomers building a curriculum vitae.
But the Centaur bodies caught the eye of astrologers and rapidly became the cutting edge of what was then the latest astrological thinking.
The first of these small planetary bodies, Chiron, named after the head Centaur in Greek mythology, was discovered in 1977 and caused an immediate stir. Astronomers still debate its nature. It has a small tail like a comet, but rotation like an asteroid. Up until 1977 rotation and tails were supposed to be mutually exclusive characteristics. Astronomers are still debating the seeming contradiction.
Careful scrutiny of photographic plates from the late 19th Century revealed that this comet/asteroid had been photographed but unrecognized more than 100 years ago. The photograph at the right shows Chiron circled and was taken in the late 20th Century.
Sophisticated computer calculations of Chiron's highly elliptical orbit indicate that it would have had a close encounter with Saturn in the mid 8th Century CE, which prevents any accurate calculation of its orbit prior to that time. Today the planetoid, some 120-150 km in diameter, rotates around the Sun in a 49-51 year orbit which crosses the orbits of both Saturn and Uranus.
A small cottage industry sprang up amongst astrologers right after Chiron's discovery trying to understand the astrological significance of Chiron. The traditional teaching in astrology is that when a new planetary body is discovered, its archetype then becomes available to everyone in the world. The discovery of Chiron resulted in books, seminars, lectures, and discussions washing through the astrological community.
By the early 1990s astrologers had begun to understand some of Chiron's significance, and the better astrological software began to include Chiron for natal charts and transits. Chiron appears to rule wounding, healing, great quests in life, and even access to the higher metaphysical dimensions.
In ancient Greek mythology Chiron, half man and half horse, was also the only Centaur who was one of the gods, an immortal. So an archetype of being half animal, half human, and fully divine begins to emerge. Chiron's orbit, bridging Saturn (the known) and Uranus (the unseen transpersonal), suggesting Chiron as a bridge between the material and spiritual worlds.
Just as that was soaking in, Pholus (pictured at right) was discovered in 1992. Named after another Centaur, Pholus was of a similar size as Chiron and had a similar elliptical orbit. By this point, astrologers were dusting off their long-forgotten books of Greek mythology. Good thing, too, because by the end of the decade more than 16 Centaur bodies had been discovered in the same neighbourhood as Chiron, all with elliptical orbits, and there may very likely be more discovered as astronomers warm up to the discovery challenge.
Greek mythology records several hundred Centaurs, so names will not be problematic for new discoveries. The Centaurs, minor figures at best in Greek mythology, are best remembered for drunkenness, rape, and pillage of the countryside.
But a handful were good guys, like Chiron, Pholus, and Asbolus (another newly discovered Centaur planetoid). The story of Pholus is the story of self-sacrifice for a greater good, and Asbolus was known as a great seer and counsellor. The Centaur, Nessus, the third Centaur planetoid discovered, was more typical of the Centaurs and was best known for lying and betrayal.
Yet the naming of the Centaur planetoids got a little more complicated at the recent turn of the millennium when one of them was named Chariklo, who was not a Centaur at all but was the woman who was Chiron's wife. And there's still many more discovered which are to be named.
Ephemeris freeware for the known Centaurs is now available in Win32 format. Check the website periodically for updates, and be patient because the server is sometimes down so you may have to return a few days later.
The final understanding of this new dimension in astrology is not and certainly cannot be in yet. As new planets beyond the orbit of Pluto are discovered the meaning of the Centaurs will change.
There will be other changes in our understanding as other new planets are discovered. But the Centaurs will always remain as the early harbingers of bigger changes which later entered the world of astrology.