Below is a 2 dimensional representation of a 3 dimensional concept in which the 3rd dimension would be time. If you want to picture it as a 3D object it would be a helix, like a spiral staircase. Continuing the analogy, if you climb up a spiral staircase you will end up facing in the same direction that you started but you will be 1 floor higher which is equivalent to the passage of 1 year. The eight points where the spokes meet the circle are the sabbats. The sabbats are the major celebrations of the Wiccan year with the full moons being the minor celebrations, or esbats. Movement through the year continues around clockwise as indicated by the arrow at the bottom.

I wondered why the people who devised this wheel had decided to use Celtic names and after rummaging about for a while I came across the following on Wikipedia :-

"There appears to be no surviving evidence that the eight festivals described in this article were formally observed as a 'set', and the complete eightfold Wheel of the Year was unknown under that name prior to modern Wicca, as far as we know.[5] In early forms of Wicca only the cross-quarter days were observed. However, in 1958 the members of Bricket Wood Coven added the solstices and equinoxes to their original calendar, as they desired more frequent celebrations. Their High Priest, Gerald Gardner, was away visiting the Isle of Man at the time, but he did not object when he returned, since they were now more in line with the Neo-druidism of Ross Nichols, a friend of Gardner's and founder of the Order of Bards, Ovates and Druids.[15] Lamond, Frederic (2004). Fifty Years of Wicca. Sutton Mallet, England: Green Magic. pp. 16-17. ISBN 0-9547230-1-5."

In the above quote the section up to the [5] is taken from Hutton, Ronald. The Pagan Religions of the Ancient British Isles. Oxford, Blackwell. pp. 337-341. ISBN 0-631-18946-7.

If you would like to read the Wikipedia entry for the Wheel of the Year click here.

The Bricket Wood Coven must have been real party animals. Four sabbats and thirteen esbats a year isn't enough. We want more !

Fair enough, since we now know that the wheel is composed of two separate parts, let's dismantle the wheel. The important point to note is that one set of dates is determined by astronomical events and the other by fixed dates in the calendar. The dates of the astronomical events are referred to as quarter days and the calendar dates with Celtic names are referred to as cross quarter days. As a result some people believe that the cross quarter days should not be fixed to the calendar dates but should be placed at the mid point between the quarter days.