My introduction to astrology was through the horoscopes, though I always thought of them as the same thing. I took a course in Astrology and learned how to cast charts. I never got really good at interpreting them, as that does take some study and imagination.
As I learned more about astronomy and biology, I find it impossible to believe in horoscopes at all. That is not to say that I'm dismissing the impact of celestial bodies on people, I just don't think this influence can be distilled down to a handful of celestial bodies.
Our calendar has never been fixed. going from 10 months to 12--on a whim. It has only been a few hundred years when most of the world even used the same calendar. Of course the universe does not conform to our arbitrary labels since it is constant state of flux, and requires correction periodically.
Mel previously mentioned Ophiuchus, illustrating that the astrological signs we commonly follow don't adhere to the actual constellations. Of course there is disagreement on whether there should be a 12, 13, or even 14 astrological signs...
That vast majority of the material of our universe (dark matter and dark energy) is currently unknown to us. Perhaps it is unknowable--who knows.
I'm all for seeking hight levels of knowledge. Perhaps astrology and religion can provide a path to a more profound understanding of the nature of the universe, but more often they seem to lead more restricted understanding