They should have seen it written in the stars: a US planetarium says that the Moon's gravitational pull has pushed zodiac signs as we know them out of whack.
The Minnesota Planetarium Society says the alignment of the stars that determines zodiac signs has been altered by about a month.
"When [astrologers] say that the sun is in Pisces, it's really not in Pisces," says Professor Parke Kunkle, a member of the group's board.
The ancient Babylonians based a person's zodiac sign on what constellation the sun was in on the day of their birth.
These signs are then used to divine what happens in a person's day to day life, in the form of a horoscope.
But the Minnesota Planetarium Society says the Moon's gravitational pull has made the Earth wobble on its axis, thus changing traditional star signs by up to a month.
The astronomer, whose profession generally looks down on astrology, has rubbished the link between birthdays and personality traits.
"Sure, we can connect harvest to the stars," Professor Kunkle says. "But personality? No."
"Historically, people looked at the sky to understand the world around us," he says. "But today I don't think people who are into astrology look at the sky very much."