Primary directions are easy to understand, provided one keeps in mind that their name is derived from the primary motion of the earth around its axis. If they are treated like a rarefied form of transit, which quite often is the case, then confusion is not far away.
Before there can be direction, there must be a reference from which to direct. This reference is the radical chart or the radix. The radix or root has its name for a reason. The positions of the houses and the planets remain stable, they do not change. They are rooted. This has to be deeply anchored in one’s mind.
Next, it has to be clear what is directed to what. Here two terms are used. Promittor and Significator. A Promittor, as the name indicates promises something. A Significator signifies something. So far, so good, but it is here that the authorities differ from one another as to the number of Significators and to which “moves”. Some say it is the Promittor that moves to the Significator. Others that the Significator is moved to the Promittor. As we will discover, the whole debate proves to be pointless once one understands how directions work!
The radix holds at birth pure potential. All that is contained in it is a promise for the future. This potential is not released immediately. It unfolds in the course of the life, and can be seen for example in major events that befall the native. This means that each sensitive point in the chart is a bearer of potential and so is also a Promittor. The events can then be understood as being represented by a Significator. Where are the Significators found? They are also in the chart and can also be Promittors. Again, which sensitive points should be used as Significators is a matter of debate among astrologers. Many follow Ptolomy who only allowed five; MC, Ascendant, Sun, Moon and Part of Fortune. Others argue that the natural and accidental Significators of a particular event should also be taken from the radix. For example for the Marriage of a man, Ascendant, Lord or Lady of the 7th house (accidental ruler of the wife), the Moon and Venus (natural rulers of women) should be considered. I will leave it to your discretion which Significators to use.
Now we can answer the question how the Promittors and the Significators are brought together. Quite simply through the primary motion of the earth or of the celestial sphere around the earth (both viewpoints are correct). Neither the Promittor nor the Significator moves as such. It is the earth that moves, namely through rotation about its axis. And it is this clockwise motion that directs a Promittor towards a Significator. It is this rotation, when converted to time that provides the ‘score’ for the unfolding of the life events. If you recall in the article “Priming up for Primary Directions” we discussed how the circle of the equator can be divided into 360 degrees and that each degree of longitude may also be converted to or expressed in sidereal time. You may also recall that the terrestrial sphere and the celestial sphere share the same equator, the only difference being that on the terrestrial equator each degree defines longitude and the beginning point is the meridian that passes through Greenwich while on the celestial sphere each degree defines right ascension and the beginning point is at 0 Aries. All that you have to remember is that the primary motion of the earth brings the position of the Promittor to the Significator. Imagine that the radix positions of the Promittors are all imbedded in an amber sphere and their projection to the equator is also marked. Around this sphere is a thin glass sphere on which the Significators and their projected paths to the equator are also marked. The amber sphere revolves clockwise and carries the projection of the Promittor to the projection of the Significator. The arc that is needed to bring the Promittor to the Significator is then measured. This measure is then converted into time. The rule is that each degree is also equal to one year of life. There are two conversion formulae that are used. That of Ptolomy, 1 degree = 1 year. That of Naibod, which is considered more accurate, 59 minutes 08 seconds = 1 year. As all directions are projected onto the celestial equator, the seemingly complicated (and frightening!) spherical trigonometry is merely a means for achieving this.
One thing you must not do is to treat directions like transits or secondary progressions, where the planets or other significant points are really “moved”. This is the source of most confusion, and this is where the argument begins that it is the Significator that moves to the Promittor, because the Significator is thought to move with secondary motion.
Let us look at one of the simplest directions to calculate, that to the MC. It is simple because all geographical positions that share the same longitude have the same meridian and therefore have the same right ascension. You can see this if you look in your Table of Houses. At the top of the Table usually the position of the MC for every 4 minutes of sidereal time is given along with the RAMC, the right ascension of the MC. The values for the Ascendant and houses 11, 12, 2 and 3 are then listed by latitude. There is only one value for all latitudes for the MC.
Let us say that your birthplace was 50 degrees N latitude and that the MC of your chart is at 0 Aries. Mars, Lord 10 is at 0 Gemini. Now you want to direct Mars, the Promittor, to the MC. The RAMC of Aries is also 0. The RA (right ascension) of Mars at 50N latitude is 57º 49′. This is the interval needed for the projected point of Mars on the celestial equator to reach that of the MC. This is the direction. Converted to time this would be 57 years and 10 months, if you use ptolomaic conversion or 58 years and 6 months if you use Naibod.