We cross-referenced the psychometric personality data of ~ 1 million people with their zodiac astrological signs: 1) There is a small but statistically significant effect of zodiac sign on personality controlling for demographic and attitudinal variables 2) These observed personality correlations correspond strongly with LLM-generated "stereotypes" of astrological associations with personality 3) This association of observed astrological effects with astrological "stereotypes" is mediated strongly in auxiliary surveys by how frequently people read horoscopes and generally subscribe to astrology 4) Zodiac effects among people who never read horoscopes are a quite precisely estimated zero, while effects among people who read horoscopes everyday are on the order of 0.2 sds - on par with or larger than most psychometric associations found in social science