Many Astrologers, this writer included, have had the uncomfortable experience of announcing that Jupiter is in Cancer, only to have it pointed out that it can be seen actually shining from the constellation Gemini. We only have to look at the sky to see that our tables are out of date. Astrology is stuck in a time-warp. And it’s been stuck there for a long time.
Let’s go back to when its sister subject, astronomy, was liberated from its own time warp. That happened about 500 years ago. A Polish churchman, Nicolaus Copernicus, wondered whether it made more sense to think of planet Earth encircling the Sun rather than the other way round. ‘Nonsense’, many people said. ‘You can feel that the Earth isn’t moving! It must be the centre of the universe.’ ‘And anyway, that’s what the Greeks said.’ Or words to that effect. Other people pointed out that if the Earth wasn’t the centre of the universe it would contradict passages in the bible.
To contradict both the Greeks and the bible was a bold move indeed. Learning in the universities in the sixteenth century mainly involved studying what the ancient Greeks had written. People had more confidence in the insights of these great thinkers from over a thousand years previously than they did in the evidence of their own eyes and senses. The standard astronomical text was Ptolemy’s Almagest, which expounded Aristotle’s understandings from even further back. It clearly and unequivocally stated that the Earth was the stationary centre of the cosmos. 
But as we now know, Earth and the other planets of the solar system revolve around the Sun, so the ancient Greek system didn’t quite explain the observed movements of the heavenly bodies through the sky. Ptolemy and his predecessors knew this, and devised some intricate circles within circles to explain it. It took a man as clever as Copernicus, knowing that Nature is economical, to come up with a simpler way to explain the observed facts: it all makes much more sense if the Sun is the still centre, not the Earth.
Over the next hundred years other clever people took up the baton from Copernicus: the Danish astronomer Tycho Brahe made detailed observations of the movements of the planets. His Austrian assistant Johannes Kepler used that data to develop the three laws of planetary motion. Kepler’s Italian contemporary Galileo Galilei pointed a telescope at the sky and discovered that there were far more stars than could be seen by the naked eye, that Venus had phases just like our Moon, and that Jupiter had moons of its own. The heavens were no longer fixed. Astronomy was liberated.
What is curious to me is that these men all also studied Astrology. Some of them were court Astrologers, casting horoscopes for the kings and emperors of the day. These were intelligent, independent-minded men. I find it hard to believe that they did this just to appease the rich and powerful. But they didn’t bring Astrology up to date.
Astrologers today sometimes appear like mediaeval scholars, ignoring the evidence of their eyes and placing more trust in their books of tables. Why wasn’t Astrology liberated along with Astronomy?
One reason, I suspect, is that Astrology was in even more of a time warp than Astronomy. The ancient Greeks came up with a theory of the movements of the planets, but they were already out of date with Astrology.
The planets in our solar system circle around the Sun on a flat plane, the plane of the ecliptic. Astrology, the study of the stars, looks beyond the solar system out to the Milky Way, the line of innumerable stars of the rest of our galaxy that we can sometimes see on a clear night. Our galaxy is also on a flattish plane – the Milky Way that we can see is the thickest part of it. As the planets move around the Sun in our solar system, so does the solar system against the background of our galaxy – but much more slowly.
The Astrology that we still use today had its last update not 500, not 2000, but over 4000 years ago, in what is now Iraq. Those Astrologers looked at the plane of the galaxy and divided it into twelve equal segments of thirty degrees, making a complete circle of 360 degrees. (They must have been obsessed with the measurement of time. It is because of them that an hour has sixty minutes, another division of 360.) They chose a constellation that occurred in each segment, and named the segment after it. The year was also divided into twelve months. As the Earth moves around the Sun through the year, we see the Sun in a different section of the heavens, in front of one segment of the galaxy after another, a month for each segment. For those ancient Astrologers their year started at the spring equinox on March 21st, when the Sun was in front of the constellation of Aries.
But just as the planets move, so does everything else, although more slowly. And planet Earth also wobbles, very slowly. As seen from Earth, every 2200 years or so the Sun appears in front of another segment of the galaxy on March 21st. It left Aries long ago and has now almost reached the end of Pisces. In a few hundred years’ time we will be in the Age of Aquarius, when that segment of the galaxy appears behind the Sun on the morning of the spring equinox. It has been said of modern science that the significance of any breakthrough can be measured by how long it holds up further innovation in a given field. As we still count Aries from the 21st of March, those Astrologers must hold the record for one of the greatest breakthroughs of all time.
I find it interesting that Astrology has persisted at all, despite its inaccuracies, and despite comprehensive pooh-poohing from modern academic astronomers and cosmologists. It just won’t fade away. It is as if enough people down the centuries have been convinced that there is still a baby somewhere in all that bathwater, and it’s worth trying to keep it alive. I feel a gratitude to the generations who have kept faith with it, enabling us to look at it now with fresh eyes.
So what should we do now? Should we just update all the Astrological tables and leave it at that? Will that bring Astrology into the twenty-first century? That feels to me like trying to update an obsolete computer program. There is so much that could be revisited – the house systems, the associations of planets with signs, even the names and symbology of the constellations themselves. After all, Microsoft has stopped issuing updates for Windows XP, and that’s only about ten years old. Maybe the astrological software is overdue for a comprehensive rewrite.