An Astronomical Argument
In our own time there has been much speculation about the dawning of the Age of Aquarius, that now almost mythical event said to be brought about by the precessional movement of the Vernal Equinox point backwards from Sidereal Pisces into the last degree of Sidereal Aquarius. The problem is no one knows how to precisely identify the boundaries of the Sidereal Zodiac. The Tropical Zodiac is known without question as its boundaries are simply multiples of 30 degrees from the solstice and equinox points, which are determined by the relationship of the tilt of the Earth with respect to the Sun. But when it comes to the Sidereal Zodiac made up of the constellations of the visible background stars, there is no solid agreement.
Modern astronomy simply pegged the constellations of visible stars on the ecliptic to Spica, a relatively bright star close to the ecliptic which is now defined to be exactly 15 degrees Sidereal Virgo, but this had nothing to do with any ancient understanding of the "fixed" stars. It could be argued that Antares and Aldebaran, two very bright stars almost perfectly opposite each other and both just below the ecliptic, make the most obvious marker, but they are of no help in describing the precise difference between the current location of the visible constellations and the Tropical Signs named for those patterns roughly two thousand years ago when the two zodiacs diverged.
Many scholars have tried to set the angle based on the time difference between that time and the current era, wherein it would take about 2160 years to move a full 30 degrees. Note that if this figure (derived from multiplying 72 years by 30 degrees) were precisely correct, then the year 2000 would be exactly the right number of years after Hipparchus’ (re)discovery of precession in the Hellenistic Greek world in 160BCE. But it is impossible to know with any certainty at what date the two zodiacs were effectively codified and thus diverged; though the Vedic astrologers insist that they know that the difference is precisely 23 degrees now, while at the same time insisting that their sidereal zodiac is much older, predating Hellenistic astrology.
However, among those scholars who do argue in favor of an ancient understanding of precession, there is increasing recognition from the direct translation of texts that the ancients themselves understood the Milky Way to be one of two “great belts” in the heavens, and that one belt, the Milky Way, divided the stars, while the other belt, the Ecliptic, represented the path of the planets. In any case, weather one believes that the ancients had this understanding or not, once one does have a modern astronomical understanding of the stars, the galactic equator becomes the one absolutely unique, inevitable and incontrovertible line in the sky, bisecting the background stars. The galactic equator is the plane in the middle of the disc of the Milky Way Galaxy. The galactic equator is to the local galaxy as the Earth's orbital plane is to our view of our local solar system. Thus, the point where the line down the center of the Milky Way, representing our view of the galactic equator on edge, intersects the line of the ecliptic, stands out as the only precisely defined astronomical point in the Sidereal Zodiac. The galactic equator is the only celestial structure analogous in its certitude among the background stars to the solstice and equinox points on the ecliptic.
Once one understands this relationship it suddenly becomes clear what precise astronomical event the popularized western prophecy actually describes. When the Winter Solstice point, which is by definition the first degree of Tropical Capricorn, conjoins the galactic equator, which we can now see marks the exact boundary between Sidereal Sagittarius and Scorpio--you have but to look at the sky on a summer evening to see the Milky Way between the teapot and the scorpion, which themselves visibly mark the division between the first degree of Sidereal Scorpio and the last degree of Sidereal Sagittarius--then three signs away the Vernal Equinox point, marking the boundary between Tropical Aires and Tropical Pisces, must also at the same time exactly conjoin the first degree of Sidereal Pisces, and the last degree of Sidereal Aquarius.
According to modern astronomy, that event occurred most precisely on the Winter Solstice in 1999, when there was also a Full Moon, at perigee, on the solstice, nine days before Y2K. Thus, the dawn of the new Millennium, the one moment when virtually all of humanity came together in the awareness of one calendrical event, was also The Dawning of the Age of Aquarius.