Age of Aquarius

The Age of Aquarius, in astrology, is either the current or forthcoming astrological age, depending on the method of calculation. Astrologers maintain that an astrological age is a product of the Earth's slow precessional rotation and lasts for 2,160 years, on average (one 25,920 year period of precession, or great year, divided by 12 zodiac signs equals a 2,160‑year astrological age).

There are various methods of calculating the boundaries of an astrological age. In Sun-sign astrology, the first sign is Aries, followed by Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces, whereupon the cycle returns to Aries and through the zodiacal signs again. Astrological ages proceed in the opposite direction. Therefore, the Age of Aquarius follows the Age of Pisces.

The approximate 2,160 years for each age corresponds to the average time it takes for the vernal equinox to move from one constellation of the zodiac into the next. This average can be computed by dividing the Earth's 25,800-year gyroscopic precession period by 12, the number of zodiacal signs. This is only a rough calculation, as the length of time it takes for a complete precession is currently decreasing (because the rate of precession per year, an inverse relationship to the period, is increasing). A more accurate set of figures is 25,772 years for a complete cycle and 2,147.5 years per astrological age, assuming a constant precession rate. According to various astrologers' calculations, approximate dates for entering the age of Aquarius range from 1447 CE (Terry MacKinnell) to 3597 CE (John Addey).