What is your star sign? Are you sure? Astronomy arose from the division of the night sky in ancient times into twelve regions of thirty degrees each. Images were created from the prominent stars to enable early astronomers to recognise parts of the sky. They assigned names to these groups of stars - the constellations. They noted the regular patterns in the movement of the constellations across the sky over the passage of a year. Naturally there was a link to the natural cycles: harvests and rains, day length and weather. Thirty degrees was a convenient way to divide up the sky, but not really accurate. For most of the time allocated to Scorpio this year, the sun actually rose in a constellation called Ophiuchus. Why? The Sun Sign, also known as the Zodiac, is allocated according to the constellation into which the sun rises at that time of the year. If the sun rose in Aquarius at the time of your birth, then your star sign is Aquarius. The only trouble is the range of dates which match the sun rising in each of the constellations has changed greatly over the millennia.

Epsilon-pi, whose astrology chart (above) was done by a professional astrologer. Isn't it beautiful? It doesn't mean anything, but it looks lovely.

(Image courtesy of NASA)

Two thousand years ago, when the zodiac was created, the sun rose in Aries at the March equinox. Now the sun rises in Pisces at the same equinox. This is due to the precession of the equinoxes and relates to the fact that the earth not only rotates on its axis, but the axis itself wobbles over a period of 25,800 years, during which the positions of stars will slowly change relative to a (very old) viewer on earth. The precession of the equinoxes was discovered by the Greek astronomer Hipparchus, who lived from about 190 BCE to about 120 BCE). The reason was later explained by Newtonian physics. So we are not talking recent developments here - yet the magazines and newspapers still print those old dates. This has led to about a thirty degree shift over the two thousand years since the Zodiac dates were created. The table below will let you know what your star sign is - now. The dates given in magazines and books are what your star sign would have been had you been born 2000 years ago, and under the Julian Calendar, rather than the Gregorian one we now use.

We have eighteen days in which the sun now rises in another constellation: Ophiuchus. As we have no charts for them, does this mean these poor people have no personality? We have had a significant increase in Virgos (now forty-five days) and a huge reduction in Scorpios (only seven days).

The usual argument when confronting astrologers is that simple sun sign astrology which is not specific enough. We need to include the position of the planets. The type of reading you find in books and newspapers, they say, is just a superficial generalisation. But that is what many people accept. 'I’m a really typical Gemini' and 'He’s just like that because he’s a Sagittarius.' If there are no common features among those within a given sign of the Zodiac, then doesn't the star sign become irrelevant?

Many of the descriptions given for the 'science' behind astrology include references to Neptune, Uranus and Pluto, whose existence was not known to the creators of astrology. Pluto is no longer officially a planet. If it was, then there are a large number of other equivalent bodies out there which are just as big and significant. So why are they not appearing in astrology? The astrology's accuracy is convincingly sold on the fact it is two thousand years old. Don't you have to question something which has not changed in human understanding in two thousand years? Everything else has!

There have been many statistical tests done to see if there is any correlation between the sun sign and the careers of people. John D. McGervey, took the 1965 listing in American Men of Science, of 16,634 scientists listed and tabulated them according to the star signs. He did the same with the 6,475 listed in the 1973 Who's Who in American Politics. Those are a very narrow groups of people - all have achieved highly enough in science or politics to be recorded in a Who's Who. Politics attracts a very specific sort of personality, so they would be much more alike than the general population. Surely these lists would have shown some skewing if there was any astrological influence on careers. The distribution was even, right across all twelve signs of the Zodiac. No skewing in favour of one sign or against another could be detected.

Survey at least ten people whose birth date indicates their star sign has changed since the original dates were drawn up.

Take a set of astrological readings from any source - magazine, newspaper or book. Ask people to rate the accuracy of their reading out of 10 for three readings presented to the candidates in random order:

1. the star sign they think is theirs.
2. their 'correct' sign according to the table above.
3. a reading for one of the other signs.

Analyse your data. Was either the original star sign or the new one reliably selected?