You probably already know what yourzodiac sign is. For example, if you were born between March 21 and April 19, your sign isAries, the ram. But that’s not the whole astrological story, as the interactive above shows. When you enter the date, time, and location of your birth, the interactive returns your zodiac sign, your Moon sign, your rising sign, and your true sign.

Your Moon sign is where theMoon was when you were born, and your rising sign is the zodiacconstellation that was on the eastern horizon—that is, rising—at the moment of your birth. But what is your “true sign”?

Your zodiac sign has to do with the position of the Sun at your birth, but those dates are where the Sun was 2,000 years ago. About every 26,000 years,Earth’saxis wobbles in a circle. Now Earth’s axis points atPolaris, which is why all the stars revolve around thatstar in the night sky. In 12,000 years it will point atVega, and that will be thepole star. Because of this wobble, called theprecession of the equinoxes, where the Sun was when you were born may not be your zodiac sign according to astrological tradition. Your true sign is what constellation the Sun was actually in at your birth.