The ancient Babylonians split the sky up into twelve 30 degree arcs and picked constellations that were visible within those arcs to use as references when doing astronomy and calendar stuff. That idea kicked around the ancient Mediterranean for quite a while, until the Greek version got codified by Ptolemy around 200AD, and that's more or less the version we're stuck with. So the star signs we know are the Greek version of the most visible constellations that fit into even 30 degree arcs in the night sky, as of 1800 years ago.
Your main astrological sign (sun sign, or just "sign") is which 30 degree arc the sun was in when you were born. The rest of your chart is the parts of the sky where the moon and all the planets out to Saturn were at that time. More modern charts add Uranus, Neptune, and Pluto.
Each of the signs is associated with a big enough grab bag of character traits, while the planets represent which part of your life those traits are supposed to apply to best. The exact nature of those is pretty much Calvinball though, because it's all made up and nobody is going to read Ptolemy.
The full chart is a pretty neat thing that would make for cool basis to a magic system for your next D&D campaign, though it makes me sad when people try to apply it to real life.
The ancient Babylonians split the sky up into twelve 30 degree arcs and picked constellations that were visible within those arcs to use as references when doing astronomy and calendar stuff. That idea kicked around the ancient Mediterranean for quite a while, until the Greek version got codified by Ptolemy around 200AD, and that's more or less the version we're stuck with. So the star signs we know are the Greek version of the most visible constellations that fit into even 30 degree arcs in the night sky, as of 1800 years ago.
Your main astrological sign (sun sign, or just "sign") is which 30 degree arc the sun was in when you were born. The rest of your chart is the parts of the sky where the moon and all the planets out to Saturn were at that time. More modern charts add Uranus, Neptune, and Pluto.
Each of the signs is associated with a big enough grab bag of character traits, while the planets represent which part of your life those traits are supposed to apply to best. The exact nature of those is pretty much Calvinball though, because it's all made up and nobody is going to read Ptolemy.
The full chart is a pretty neat thing that would make for cool basis to a magic system for your next D&D campaign, though it makes me sad when people try to apply it to real life.
What about Indian astrology? Is it a branch from the original Babylonian?