No Agreed Start Date

Unlike the ages that precede it in this scheme, the Age of Aquarius has not yet been reached by any measure that commands general agreement, which makes its proposed start date the clearest illustration of how unsettled the whole ages framework is. Writers who divide the Great Year into twelve even 2,150 year segments starting from an assumed date for the beginning of the Age of Aries typically place the Aquarian transition somewhere in the twenty first to twenty sixth centuries CE; writers who instead try to match age boundaries to the true, unequal extent of the zodiac constellations in the sky often arrive at very different dates, some placing the transition decades or centuries earlier or later than the even-division estimates.

No professional astronomical body publishes an official date for the transition, since precession is a continuous, gradual process with no natural marker for when one constellation "ends" and the next "begins," and no consensus method exists within the astrological literature itself for resolving the disagreement between the even-division and constellation-boundary approaches. This entry accordingly records the range of proposed dates rather than adopting one, consistent with how contested the question remains among the writers who study it.