A short guide to Ptolemaic primary directions

Reading here and there I see that primary directions are seen as very difficult and occult. It is not like that.

Ideas which are behind are very easy to grasp, and modern software can do all the calculation for us: on the other hand people who have learned them generally use them as a way to show how clever and expert they are.

But culture is democratic  -in Italy we say culture is left wing 🙂 and for an Italian using complicated formulae mixed with macaroni Latin is just a way to muddle waters and hide mistakes and lack of real education. (( latinorum ))

Moreover Rumen Kolev ((Rumen Rumen Kolev, Primary Directions I and II)), who is well known in Anglosaxon world, for his excellent work with primary directions explains in a very difficult way, so I prefer arrange numbers in an easier way, following Giuseppe Bezza and Marco Fumagalli (( Marco Fumagalli.  I moti del cielo ))
Anyway it’s not a different method,  just numbers are collected in a more sophisticated 🙂 way.

As we know, since the beginning astrologers were divided into a group who believed that stars were symbols and the ones who believed that stars influenced human life because of  astronomical laws. The main one – explained with the sophisticated Aristotelian/Ptolemaic model is the perception of two motions of the Earth, the yearly revolution (which became the epicycle of planets) and the daily rotation (known by the Ancients as the Prime Mover). (( Geocentric model ))

Primary directions are the primary predictive method (combined with profections and solar returns)  not just because they were always the favourite method of ancient astrologers, on which they based several famous predictions, but especially because they are based on the motion of the Prime Mover, the Primum Mobile.

As Prof. Bezza writes:

The astronomy of primum mobile is opposed to the one of secundi mobiles…..The first, which concerns of the law of daily motion, concerns what in the world of generation  has the characteristic of  continuity; the second, concerning planetary motion, is linked with appearances one different from the other, and in the world of generation is linked with everything is different and opposite.

In this sky are the roots of time. There is no difference in quality, but in time. One belongs to the planetary spheres, which show it running through their orbs. The second is based on the same planets, which are  dragged, rupti, by the breathless motion of the first mover. Putting together these two things is the greater part of the art of forecasting. (( Giuseppe Bezza, Le tavole del Primum Mobile nel Medioevo, in Astronomical amusements (Mimesis Edizioni, 2000). ))

The following is a short and simple – I hope so – way to calculate Ptolemy’s directions – semiarc method, without logarithms, sinus, trigonometry, rotating spheres and all the paraphernalia that generally accompany the subject.

We need just Morinus software – we can download for free here because we need a couple of data from its speculum, and two ratios, that’s all. Then we will have all the secrets of the Universe in our hands.


Andrea Argoli in his book – very appreciated by William Lilly,the  Tabulae Primi Mobilis, in fact explains:

Eternal Providence of the Perfect and High God teaches that this lower sphere should be ruled by second causes and all those activities, both inner and outer, concerning human beings come from God, through Angels and Celestial bodies, and that the greater part of them is written – as Albert the Great writes in his Mirror of Astronomy, in the book of the Universe, which is the the Scroll of the Sky.

There it is shown with the greatest order, what is needed for ruling so much a great work, not  just for the influences to which a human being is subordinate, but their  time and ways which cannot be changed.

They are dependant on the motion of directions, which are the executors of these influences and of God’s will. (( Andrea Argoli, Le direzioni astrologiche. Trattato di calcolo delle direzioni primarie con le tabelle delle ascensioni oblique e rette. (Il Pavone, 2008). ))

So this is the idea behind this technique in the most important astrologers of every time: there is not so perfect tool of prediction as primary directions.

But what is a direction?

Let’s start from symbolic directions:

our example chart
our example chart

the symbolic direction here will be the arc between two points taken on the ecliptic, from 6 Leo to 3 Virgo, measured according a fixed key which is 1 degree per year.

In the example chart 27 degrees are 27 ALWAYS 27 years, whatever planet we are considering.

In the same way, a primary direction  according the same Argoli:

is the arc of EQUATOR intercepted between two points in the sky; and precisely the measurement of the path of the Promissor according the motion of the Primum mobile, in order that its position will arrive to the Significator.

The two positions which should be taken into consideration by astronomers are:

– the Significator (which could be a planet or another point on  the ecliptic) shows in the sky something about life, uses, fortunes and more;

– the Promissor, which decides and promises both the good and the evil in the category of life signified by the significator, which will be fulfilled when the promissor will reach the significator.

In our example we should move  Mercury, the Promissor according the motion of the Primum Mobile, ie  against the order of the signs, till it will arrive to the Sun, the Significator.

But in this case  every point has a different speed as we will see below.

Unfortunately which was the right method of directing was not so clear in Argoli times, during 1500-1600. The same Argoli admits, some lines after his poetical preface:

After  having left behind all the methods of directing used by Ancients, because not proper to the subject and to practical experience, two methods are left to the astronomers in order to calculate directions and foresee future events.

One is Ptolemy method which he teaches with very poor clarity in the third book of Tetrabiblos and just  a few followed.

The other is the one followed by other astronomers and it is the  method used  in the tables calculated by Johannes Regionontanus and which is called rational.

Obviously Argoli follows Regiomontanus. Ptolemy’s method will be explained and “perfected” under the guide of reason -together with Ptolemy 🙂 by Placido, a monk born in Perugia in 1603 (Argoli was born in 1570).

According some researchers Ptolemy’s method as explained by Placido was anticipated by important Renaissance astronomers and astrologers, (( Giulio Verbese ((http://www.cieloeterra.it/articoli.diedo/diedo.html but see even bibliography below)). )) but Ptolemy’s method, the semiarc method, is now called and known as Placido’s method.


Whatever method we choose, we have two different groups of directions, zodiacal and the mundane directions.

Let’s come back to our example chart:

in Zodiacal ones we should move not the real body of planets but their ecliptic degree. Considering they are called “zodiacal” directions,  in this case we call it the direction of the Sun to Mercury because APPARENTLY we are moving according the motion of the signs, but this is just a fiction, in effect we are still moving Mercury degree to the Sun degree.

in Mundane ones we should move the real body of the planet with its latitude.  Again we will move Mercury, the Promissor to the Sun, the Significator.

This is the rule.

Ptolemy admits a case when it’s the significator which moves, when the hyleg – the giver of life- is in the second quadrant (between MC and DESC) In this case, which is called horimea, when the hyleg  sets in the West  this will signify the end of life. About this I gave an example here.


Directions to angles are very easy.

Ptolemy writes:

Further, in prorogations of the ascendant, the degrees of distances will be equal in number to the ascensional times of the particular latitude; but, in prorogation, from the mid-heaven, to the times of culmination; and, in other prorogations, they will be in proportion to the ascensions, or descensions, or culminations, and will depend on their proximity to the angles; as has been already said in treating of the duration of life ((Tetrabiblos, IV 10))

So when we direct to the angles we should direct using oblique ascension when we are directing a point, a star, or a planet to the Ascendant and use right ascension when we are directing to the MC.

I already gave some example of this in another post. (( See Deborah Houlding article in the bibliography. ))


The problem arises when we should direct a point to another because in this case we cannot use neither oblique or right ascension.

So let’s see how to solve this problem with Semiarc/ Placido method.

Formula is easy and intuitive; the arc of direction is the distance of the two points multiplied for the speed of the moving planet, the promissor.

The speed of  promissor is measured in temporal hours, ie 1/6 of the planet semiarc.

The point position is measured by its hourly distance, ie the distance from its meridian in hours. So this distance will be zero when the point or the planet is on the meridian, will be 6 when it will be on the ASC or DESC.

arc of direction = (distance from Promissor to Significator) * Promissor speed

so if they are in the same quadrant

arc of direction= (Promissor’s Hourly Distance  –Significator’s Hourly Distance) * Promissor’s Temporal Hour

and in different quadrants:

arc of direction= (Promissor’s Hourly Distance+ Significator’s Hourly Distance) * Promissor’s Temporal Hour

Piero Marrazzo, 29th July 1958 h.8:40 pm Rome (rectified time)

This is the chart of Piero Marrazzo, former governor of Lazio.

At the moment he is on the first pages of all Italian newspapers because he resigned because blackmailed as usual customer of trangenders and transexuals. Corrupted policemen made a video while Marrazzo was with a transexual prostitute and then tried to sell to several newspapers, included the ones owned by our Prime Minister, who is the chief of the opponent political party. Useless to explain what happened after.

The chart was rectified  with some friends, directions and mistakes mine.

Pisces rising at the Ascendant,  the ruler Jupiter is on the cusp of the 8th house. Saturn at the MC, against its hairesis, the sect, damages as better it can and wants – a day planet in an angle in a night chart.

The fall  arrives with the Sun to Saturn sextile, arc of direction 51.098 (I took the result from Morinus software) corresponding to beginning of September 2009.

result from Morinus software
result from Morinus software

Marrazzo resigned a week ago but I  understand that video is wandering between newspapers board of directors and political groups since end of July,  then to Berlusconi at the end of September and then at last it arrived in front of magistrates last week.

Let’s give details of calculation.

The information we need from Morinus are the semiarc and the meridian distance of planets, having set Placido house system.

If planets are taken in mundo we can go directly to “POSITIONS” in TABLES menu.

If we want direct planets in zodiaco, we should eliminate latitude, so we can easily go to  OPTIONS/PRIMARY DIRECTIONS/ and then choose USER. There we can set planets longitude but latitude zero.

Saturn sextile is the promissor.

Saturn is at 19 Sagittarius, so the relevant sextile will be 19 Libra.

If we consider the direction in zodiaco (with latitude zero),

19 Libra, Saturn sextile has:

semiarcus: 83.03.57

meridian distance: 56.19.31

that’s all we need to calculate

temporal hour=semiarc/6= 83.065/6= 13.844

hourly distance = meridian distance/temporal hour = 56.325/13.844=4.068

6 Leo, the Sun has in the same way

semiarcus: 72.17.39

meridian distance:  54.7.41

so the temporal hour is  12.049

and the hourly distance 4.49

Now we can use the formula:

arc of direction= (Promissor’s Hourly Distance+ Significator’s Hourly Distance ) * Promissor’s Temporal Hour

Before applying the formula we should notice that Saturn should cross the horizon, from day to night. In this case we will use day temporal hour till the Descendant and then the night hour which is always 30-day hour.

Saturn sextile is at 4.068

It will arrive to the Descendant in 6-4.068=1.93

at a speed of 13.844

direction to the Descendant= 13.844*1.93=26.71

Going through the Descendant its speed changes at 30-13.844= 16.156

From the Descendant to Sun the arc is:

6-4.49= 1,51

So the arc from Desc to the Sun will be


total arc= 24.38+26.71=51.09

it fits, true?

Easier than this, it’s impossible. But feel free to comment and ask.

Written by Margherita Fiorello, CIDA certified member, for heaven astrolabe blog @ year 2009. If you want to be notified the next time I write something, subscribe to my RSS feed.


Morinus can be downloaded at https://sites.google.com/site/pymorinus/

Martin Gansten, Primary directions: astrology’s old master Technique (The Wessex Astrologer, 2009).

Giancarlo Ufficiale, Le direzioni – Scuola Cida Roma

Deborah Houlding, An easy introduction to primary directions

Lucia Bellizia, Dirigere la sfera per comprendere gli influssi futuri, in “E’ il cielo un libro”: Acts of the second Congress of Apotelesma, 2009.

Giovanni Zattini, Anareta versus Afeta: le direzioni di Claudio Tolomeo. in Linguaggio Astrale n. 93-1993

Giovanni Zattini, Horimea, la direzione conversa. in Linguaggio Astrale n.98-1995

Giuseppe Bezza, Tetrabiblos (private translation)

Claudius Ptolemaeus, Le previsioni astrologiche (cura Simonetta Feraboli), Scrittori greci e latini (Milano: Fondazione Lorenzo Valla : A. Mondadori, 1985).



6 thoughts on “A short guide to Ptolemaic primary directions

  1. 12:08 pm che vuol dire? A mezzogiorno?
    Hai visto il certificato? Lo vogliono sapere tutti a che ora è nato Marrazzo…


  2. Hi this is amazing easier than logarithms,but i have a question
    How did you find the semiarc and meridian distance of the degrees ?
    Any reference to this
    Thank you

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