Herong's Notes on Astrology and Horoscope - Version 2.11, by Dr. Herong Yang
Zodiac Signs and Zodiac Constellations
This section describes what are zodiac signs and zodiac constellations.
In Western and Indian astrology, 12 zodiac signs are closely mapped to 13 zodiac constellation areas that are located along the ecliptic circle.
12 of 13 zodiac constellation areas are sharing names with 12 zodiac signs. One of zodiac constellation areas, Ophiucus, is not recognized in astrology.
In astrology, the ecliptic circle is divided equally with 12 zodiac signs. So each sign occupies a 30-degree area. But the 13 constellation areas are defined by the IAU (International Astronomical Union) with different sizes. The table below gives a good comparison of zodiac signs and zodiac constellation areas:
Zodiac Sign Constellation Area Aries - Ram, 30 degree Aries, 21 degree Taurus - Bull, 30 degree Taurus, 35 degree Gemini - Twins, 30 degree Gemini, 21 degree Cancer - Crab, 30 degree Cancer, 15 degree Leo - Lion, 30 degree Leo, 41 degree Virgo - Virgin, 30 degree Virgo, 48 degree Libra - Balance, 30 degree Libra, 17 degree Scorpio - Scorpion, 30 degree Scorpius, 10 degree Ophiucus, 19 degree Sagittarius - Archer, 30 degree Sagittarius, 27 degree Capricorn - Horned goat, 30 degree Capricornus, 24 degree Aquarius - Water bearer, 30 degree Aquarius, 40 degree Pisces - Fish, 30 degree Pisces, 42 degree