In astrology, it is helpful to find ways to associate a visual and visceral image to what we're trying to understand and communicate.  These images can be quite easy to remember and can succinctly impart a concept that might otherwise be difficult and time-consuming to relate.

I related one such image in a recent presentation to advanced astrology students.  We were discussing the differences between Transits and Solar Arcs.  The way that I remember how to distinguish the two is by the phrase:

Transits are like footprints in the sand; Solar Arcs are like footprints in wet concrete.

I was slightly taken aback by the group's response to the simple, yet profound image that this phrase conjures up.  There were gasps of recognition, then a verbal confirmation that the image had been indelibly etched into our collective memories.  In one sentence, we summarized and crystallized what may have previously been an ambiguous or elusive concept.

The anticipated effect of Transits on a natal chart vary dramatically based both on the particular planets involved and the duration of the Transit, i.e., how long the measurement is within orb.  Transits of the Sun, Moon, Mercury, and Venus to the natal chart are usually of such short duration that their influence produces minimal effects on the individual.  As we move progressively through the more slowly-moving planets, we see increasing durations of influence matched with a corresponding increase in likelihood of significant impact on the natal chart.

Mars Transits typically express themselves as a sort of "trigger" to get other concurrent Transits moving rather than always exerting a specific influence of their own.  Proceeding through the Transits of Jupiter, Saturn, Uranus, Neptune, and Pluto we find progressively lengthy time periods where their influences are notable.

The Retrograde phenomenon often produces "sets" of Transits where a given planet will make three (or sometimes five) exact hits to the target planet in the natal chart.  While the duration and spacing of these influences always vary, there are multiple episodes of the same type i.e., the same general expectations.

With Solar Arcs, the situation is different.  Unlike Transits, which are based on the actual positions of the planets at a given time, Solar Arcs represent a symbolic motion of the planets.  Beginning with the natal chart positions each planet and point is advanced approximately one degree a year, regardless of its inherent speed.  Solar Arcs are thus not affected by retrogrades, so an Arc involves a single episode of fixed duration regardless of the specific planets involved.

Arcs are generally accepted to be a full year in duration, beginning about six months before the exact hit and extending six months beyond it.  The influence could be described by a bell-shaped curve, with the magnitude beginning slowly and gradually building to the peak, then tapering down with its anticipated effects gradually waning.

In both Transits and Solar Arcs, the Transiting or Arcing planet imparts its own brand of energy to the natal planet or point.  The part of the natal chart that is contacted by the Transit or Arc is emphasized, highlighted, or modified by the Transiting or Arcing planet.

Next Month, we'll continue to compare and contrast Transits and Solar Arcs

May 2004

Sep. 2004

Oct. 2004

Nov. 2004

Dec. 2004

Jan. 2005

Feb. 2005

Mar. 2005