Well, it was like, "I have literally never heard of this despite being a British person who's a bit of a history buff with a sister who is a pagan druid..." so I kind of wanted to know if it was a thing. 
Astrology seems to really have been more of thing for civilisations with less cloudy weather and with formalised writing systems. The Celts were oral historians who passed most of their mythology down through poems and songs, which doesn't lend itself so well to something like a zodiac. Plus there's the fact that the Celts weren't a single unified culture so much as a bunch of little squabbling kingdoms the Romans lumped together, so even if one group did do astrology, it wouldn't necessarily have applied to all of them.
