Here is a very interesting site. http://www.thegreenduck.com/ka/NewPlanets/index.shtml
The steady stream of new planets being discovered in the early years of the 21st Century is reshaping astrology as well as our view of the cosmos and our own place within in.
Our old paradigm of the ancient planets plus three "outer planets" is dead. The cosmos does not end with Uranus, Neptune, and Pluto. Instead, it expands from the three "old" outer planets into a vast and as yet only partially understood new realm.
Suddenly we have Chiron, Quaoar, Sedna, Orcus, Eris, Makemake, and Haumea.
We are witnessing the birth of a new consciousness, represented by the new planets, whose images come tumbling out of the telescopes of astronomers as rapidly as they can scan the heavens.
Even the astronomers are getting excited, although for their own reasons. New technology, much more sophisticated than ever available before, is now available to astronomers to comb through remarkably more detailed images of the deep solar system. This enables them to find new planets which heretofore were impossible to locate.
Like children playing with a new toy (a more apt metaphor than you could ever imagine), they are aiming their telescopes and computers at the sky at every chance to see what's there.
While much of this astronomical exploration is ego-driven for the purpose of career advancement, the point is that astronomers are the (very) unwitting communicators of the symbols which will guide us into the new a new era of human evolution which has already begun.
These new planets represent the new energies which are awakening in us all and represent this new era of human evolution. As above, so below. That is the maxim of astrology. The "above" is changing, and that reflects the "below" which is changing. That "below" is each of us.
Western astrology is the only astrological system in the world which accepts new planets into its cosmology. All the others are locked in the ancient and sometimes Medieval schema of the seven ancient planets. These ossified systems will rapidly be left behind by the rapid changes exploding around us.
The teaching in western astrology is that when a new planet is discovered and named, the archetype of that planet is at that point available to all of humanity. What we are seeing now as planet after planet is discovered and named is an abundance of new inner energies available to the human race.
Right now, your humble webmaster is working flat out just to keep up the the new planets as they are announced and attempting to sort out the meaning of each one. It needs to be done quickly because we barely have one planet figured out, and bingo! There's another new planet.
In this rush of discovery, the pattern of the patterns has not yet emerged, and probably will not for a little while as the full complement of new planets as yet is not discovered. But sooner rather than later the patterns will gradually emerge.
What is clear is that the old 10-planet world of 20th Century astrology is dead. By decade's end we may well be in a fifteen or twenty-planet astrological world if the current rate of planetary discoveries continues, and there's no reason to think the rate of discovery is going to decrease.
Open up your hearts and your souls. These new planets represent the new world unfolding before us and within us. Embrace the new energies and walk forward. Ignore the siren call of the old order in its death throes. They are just dinosaurs stuck in the tar pit of their own density. The rest of us must keep moving on. The 21st Century beckons.
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Chiron is a comet/asteroid that links the old astrological planets (up to and including Saturn), with the new ones starting from Uranus. It's orbit jumps from that of Uranus to that of Saturn. It is the wounded healer, and reveals where healing or the need to heal occurs in our lives.
Of the other planets mentioned here Orcus and Quaoar have orbits close to Pluto's in orbital duration and radius. They represent the final two to complete 12 planets. The other planets are much farther out, starting from an orbital duration twice that of Pluto and going to orbits in the tens of thousands of years. They represent another level of astrological interpretation in my view.
This site, however, is probably the only one that addresses these new planets, which I think are important for any serious astrologer to know.