Open almost any horoscope today and it will tell you the Sun is in Scorpio. Yet if you could switch off the daylight and look behind the Sun, you would find it standing in front of the stars of Libra, the Scales. The Sun crossed into Libra on October 31 and will stay there until November 23. So why the difference?
Why the Calendar Dates Drifted
The traditional zodiac is tied to the seasons, not to the stars. It begins at the spring equinox and divides the year into twelve equal slices of 30 degrees. Around two thousand years ago, those slices matched the constellations that gave them their names fairly well.
But the Earth wobbles slowly on its axis, like a spinning top. This motion, called precession, completes one full circle in about 25,800 years and shifts the equinox by roughly one degree every 72 years. Over the centuries, the signs and the constellations have drifted almost a whole constellation apart. The names stayed the same, but the sky moved on.
Thirteen Constellations, Unequal Seasons
In 1930 the International Astronomical Union officially fixed the boundaries of all 88 constellations. The path of the Sun, the ecliptic, passes through thirteen of them, including Ophiuchus, the Serpent Bearer, between Scorpio and Sagittarius.
These constellations are not equal in size, so the Sun spends very different amounts of time in each. This season it stays about 23 days in Libra and only about a week in Scorpio, from November 23 to November 30. Then it spends around 18 days in Ophiuchus, until December 18. Virgo, the largest, hosted the Sun for some 44 days, from mid-September until yesterday.
Today's Sky at a Glance
Libra itself is hidden in the Sun's glare at this time of year, together with Mercury, which is moving retrograde right beside the Sun. Before dawn, however, look east: Mars and Jupiter shine together in Leo, a lovely pairing for early risers. Late this evening the Moon reaches its Last Quarter in Cancer and rises around midnight, lighting the second half of the night.
Find Your True Sign
Following the real sky does not take anything away from astrology; it brings astrology back to the stars it was named after. If you were born between October 31 and November 23, the Sun was most likely in Libra on your birthday. Exact dates shift slightly from year to year, and you can find the complete tables, with the meaning of each of the thirteen signs, in Astrology of the 13 Signs of the Zodiac.