The Ecliptic

Definition: [Ancient Astrological Concepts] Ecliptic means literally, "of, or pertaining to, an eclipse." [An eclipse is the passage of one heavenly body in front of another one, so that the eclipsed body is lost to view.] The definition of ecliptic we are more used to is its solar meaning. In this definition, the body being eclipsed is always the Sun. [It is being eclipsed by the Moon: a solar eclipse.]

The reason this has been so important to astrologers down the centuries is that the only time we can actually see where the Sun is, relative to the background stars, is during a solar eclipse. Normally the light of the Sun drowns out the lights of the stars, making them invisible in the day time.

Circle of the Ecliptic: The place the Sun is in against the stars seems to move. Through the course of one solar year the Sun's place seems to move through a full circle. [See the two diagrams to the right.] This circle, which can be thought of as a line drawn on the map of heavens by the movement of the Sun, is also called the ecliptic, or the 'path of the ecliptic' or the 'circle of the ecliptic.'

Section of a Star Chart of the Ecliptic The path of ecliptic in is in yellow. It is shown against the background Sun Signs of Taurus, Aries and Pisces. The horizontal line at the base of the chart, marked in hours, is the Celestial Equator.

[ Click on the above diagram for a complete version, 46 kB.]

Plane of the Ecliptic: In fact the Sun isn't moving. The Earth moves around the Sun during a year, giving the optical illusion of the Sun's movement. Therefore, the ecliptic is actually the track of the Earth's movement around the Sun. The Sun and Earth are said to lie in the 'plane of the ecliptic'. It is in this plane that the Earth rotates around the Sun.

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The Plane of the Ecliptic The plane of the ecliptic, as viewed from above the north pole of the Sun. [One rotation of the Earth around the Sun takes one year.] The Earth rotates around the Sun marking out an ellipse-shaped disk. This disk is the plane of the ecliptic. The Sun seems to us to move throughout the year against the background stars [as visible during a solar eclipse] because we are viewing it from the Earth. But it's the Earth which revolves around the Sun - the Sun's movement is an optical illusion caused by our own moving view point. If, by magic, we could stop the Earth in its orbit the Sun Sign would be forever fixed in one sign.

The Circle of the Ecliptic This chart shows the path of the ecliptic against the constellations in the summer months [northern hemisphere], starting from the Vernal Equinox right, moving through the Summer Solstice [northern hemisphere] and ending with the Autumn Equinox [northern hemisphere]. On these three dates, the Sun Sign would Pisces, Taurus and Virgo respectively.

[Click on the above for a larger version showing the Sun's position over a March to Septmber period.]

The Circle of the Ecliptic This chart shows the path of the ecliptic against the constellations in the winter months [northern hemisphere], starting from the Autumn Equinox [northern hemisphere] right, moving through the Winter Solstice [northern hemisphere] and ending with the Vernal Equinox. On these three dates, the Sun Sign would be Virgo, Sagittarius and Pisces respectively.

[Click on the above for a larger version, showing the Sun's position over the September to March period.]