12 Zodiac Signs vs. 13 Constellations of Ecliptic

Over 2,500 years ago, the Babylonians created the concept of zodiac by dividing the Sun’s path into 12 fixed 30° slices — each representing an “ideal” 30-day month. In reality, however, the Sun travels through 13 ecliptic constellations each year. To squeeze this into a 12-month calendar, the Babylonians simply dropped Ophiuchus — and the system of twelve signs lives on in Western astrology.

Plus, over time, the borders of the actual star patterns (the zodiacal constellations) that roughly correspond to the traditional zodiac signs have changed. So the dates of the Sun’s passage through them differ significantly from the astrological dates. In this infographic, you’ll see how the ancient zodiac compares to today’s ecliptic constellations and reveals where the Sun was when you were born. For a deeper look at whether there’s any science behind your zodiac sign, check out our dedicated article.