Constellations vs Signs
Observations of the rising and setting of the constellations in the
night sky were recorded as early as 1645 BC by the priest-astrologers of
ancient Babylon. They served not only to mark the progress of the
year, but as important tools in the priestly work of divination.
Some time later, around 550 BC, the Babylonian zodiac was changed to
be divided into twelve equal segments. Although this concept went
through several evolutions as knowledge traveled through the Egyptian,
Greek, and Roman civilizations, it is still used as the basis for
Western Astrology today.
As the earth moves around the Sun, it travels along the same path, year in
year out. This path is called the ecliptic. The
ecliptic is the plane in the sky on which the sun, moon, and planets
travel. A plane is just a flat or level surface.
From our vantage point here on Earth, when we look at the Sun we are
always looking across the plane of the ecliptic, like looking across the flat
surface of a CD towards the hole in the center.
Looking Across the Plane of the Ecliptic
Far out in space,
past the orbits of all the planets, lie the stars of the constellations.
The constellations, however, do not match up exactly with the Signs of
the Zodiac. The constellations range in longitudinal size from 14º
(Cancer) to 47º (Virgo), whereas the Signs are all of equal size...30 degrees.
Constellations vs Signs
Wherever the Earth is along its path around the Sun, one
of these signs is behind it. The Sun always appears to be in front
of the opposite sign, obscuring it from our view. And so, we say that
the Sun is "in" that sign.