I believe it started on 8 April 1998.

The Age of Aquarius is one of twelve Ages defined by the precession of the equinoxes. The Sun's position at the equinox currently takes about 25,000 years to travel all around the zodiac, and each Age lasts 2,100 years or so. It is generally accepted that there is a long period of transition between Ages, and there is a lovely opportunity to celebrate the Dawning of the Age of Aquarius on 6 April 2000.

For decades now people have been saying that the Age of Aquarius was on its way in, but nobody could really say exactly when it would start. The problem is the way modern Western tropical astrology works. Each sign begins at 0°, 30°, 60°, etc from the Sun's position at the equinox (measured along the ecliptic), and that works very well, except when it comes to determining the Great Ages, which involves measuring the equinox position itself.

Various solutions:

Strictly, according to tropical astrology, the equinox Sun is always at 0° Aries, and the Ages are irrelevant because we would always be at the cusp of the Ages of Aries and Pisces, but that isn't very interesting.

We can use the boundaries of the constellations as defined by the International Astronomical Union. The Age is named after the constellation that the equinox Sun lies in front of. This is the usual view, but it has several problems:

1. The International Astronomical Union (or some substitute body) may amend the constellation boundaries, and indeed the drifting of stars relative to each other makes this very likely over a long period. In this definition, a timetable of the Ages can be only provisional.
2. The ecliptic currently passes through thirteen constellations including Ophiuchus, and not in equal measure. The portion of the ecliptic in Pisces is very long, and that in Scorpius, for instance, is very short. This creates wide disparity in the lengths of the Ages, and would imply an Age not named after one of the traditional twelve constellations. This would of course be OK, but it is not what is generally understood to be the system.
3. The Age of Pisces in this definition is much longer than average, and we wouldn't enter the Age of Aquarius for another two or three hundred years. Again, this is not generally what is believed.

I wanted to find a solution that mirrored the equal division of the ecliptic into twelve, and the making of the division to be the best fit to the twelve zodiac constellations. Ideally, there would be a reference point (that obviously can't be the equinox itself), and I believe I have found it: the intersection of the ecliptic and the galactic equator.

This nicely reflects the way the signs are determined by the equinox, which is the intersection of the ecliptic and the celestial equator, and isn’t subject to the vagaries of long-term drift. According to this definition, the Ages begin when the equinox Sun is 0°, 30°, 60°, etc, along the ecliptic from its intersection with the galactic equator. It is a matter of co-ordinate conversion that can be done by any good astronomical program. The Age of Aquarius begins when the point ecliptic longitude 270°, ecliptic latitude 0° is galactic latitude 0°. (There are of course two intersections between the galactic equator and the ecliptic, and it doesn't matter which is chosen as the reference point as far as dating goes, but I am going for the intersection in Sagittarius.)

The margin of error in my calculations is more than I would have liked, but I am fairly sure that the above co-ordinates are true at some point on 8 April 1998, and strongly believe I am not more than a day or two out. You may like to try it for yourself, and I'd be very pleased if you let me know your answer. E-mail me on william@pavilion.co.uk.

The advantage of the galactic definition is that for as long as there is the Earth, there will be the ecliptic and the galactic equator, and barring unforeseen circumstances such as the alteration of the Earth's orbit or axis of spin by a passing asteroid, their relative positions are near enough predictable. The only disadvantage I can see is that the galactic equator might be re-defined slightly over the long term as our observations become more accurate, or our solar system moves away from the galactic plane.

To distinguish the Great Ages as defined galactically, I propose calling them Galactic Ages. I am also using the term Galactic Age as a measure of the progress through the current Age. In my Lunar Tree Calendar, I give the Galactic Age for the start of each lunar month. For example the Galactic Age on 9 December 1999 is Aquarius 0° 1' 24". This is the ecliptic longitude of the point where ecliptic latitude = galactic latitude = 0°, reversed so that longitude 270° is Aquarius 0° and 300° is Capricorn 0°.

See table of dates for the Galactic Ages.

The system of Galactic Ages is very specific to our planet, and should be regarded in that light. They are a kind of meta-astrology of long-term planet-wide developments. I also think that the Great Year of all twelve Galactic Ages can be divided into four quarters (Great Seasons?) of three Ages each, and that each Great Year starts with the Age of Scorpio.

The start of the Age of Leo coincides roughly with the end of the last Ice Age, and the Age of Taurus with the start (?again) of civilisation based on agricultural settlements. This may mean that the Age of Aquarius will bring similar big changes. I do not think that any change will come suddenly, but will instead be a part of a more gradual process (like the end of the Ice Age).

The Age of Pisces has been associated with Christianity. Pisces is also about nurturing, deep emotions and psychic power. Aquarius is an air sign, and is more about mental energy than emotions. It is also about invention, spontaneity and unconventionality. It also brings the hope of more democratic and well organised structures, which nevertheless tolerate and even celebrate diversity.