...and each and every one of them was able to demonstrate, using empirical methods, that they were right. Their observations are provable and can be reproduced by others and have been tested and found to be sound down the centuries. It's that funny mumbo-jumbo thing called "science".
Astrology, on the other hand...
Oh dear, don't get me started. I know it's a waste of breath, given that the enthusiasts for this pseudoscience will cling to their beliefs in the face of all reason and will continue to perpetuate what is essentially a con-trick.
But, as has been pointed out, if a pharmaceutical company brought to market a contraceptive pill which had no discernible effect on fertility it would be sued by trusting customers who found themselves pregnant.
As Dawkins has written: "If astrologers cannot be sued by individuals misadvised, say, into taking disastrous business decisions, why at least are they not prosecuted under the Trades Descriptions Act and driven out of business.
"Why, actually, are professional astrologers not jailed for fraud?"
It's a good question.
I'm sorry, but astrology is another manifestation - along with crystal healing, reiki and other pseudoscience - of a creeping irrationalism born, I fear, of the despair most people feel when they feel unable to improve their lives and thus feel themselves to be at the whim of mysterious celestial and impersonal forces.
Or, bluntly, it's bollocks.