At least according to Tarot.com astrologer Jeff Jawer, who says the 13th sign Ophiuchus doesn't apply to us Westerners:
"When we look at the astrology used in the Western world, the seasonally based astrology has not changed, was never oriented to the constellations, and stands as … has been stated for two millenniums. Astrology is geocentric. It relates life on Earth to the Earth’s environment, and seasons are the most dramatic effect, which is why we use the tropical zodiac."
Phew, that was close!