Probably the best software currently available for calculating primary directions is the freeware program Morinus , named after the French astrologer Jean-Baptiste Morin (1583-1656). It runs on every Operating System where Python and wxPython are available (including Linux, Unix, Windows and MacOS) and is available as a free download at https://sites.google.com/site/pymorinus/ .
Morinus comes in two versions: modern and traditional. The only minor drawback of this excellent program is that you can only enter the coordinates of the birthplace to the nearest minute of arc. Most other astrology programs allow the birth location to be entered to the nearest second of arc. This slight imprecision in the initial entry of birth data means that primary directions calculated with the program may be off by a couple of weeks. Nonetheless, I highly recommend the Morinus software for use with this text.
Readers who use Janus 4 software will be able to calculate primary directions with the methods of Ptolemy and of Regiomontanus, both in the zodiac and in mundo.
Readers who have Solar Fire software will be able to calculate mundane primary directions. Unfortunately, Solar Fire does a poor job with primary directions, as it does not allow users to calculate zodiacal primary directions with the methods of Ptolemy or Regiomontanus. Instead, the modern van Dam method is available. On the other hand, Solar Fire has a useful Star Parans report which can be set to display local sidereal times or LST angles for the rising, culmination, setting and anti-culmination of planets (in the Preferences Misc menu). These sidereal times in combination with the local sidereal time of birth enable you easily to calculate primary directions to the ASC and MC and between planets with the Placidus semi-arc method, if you wish to do so by hand.
CHAPTER ONE : The Sky Moves and Carries its Spots with It
Walking in the shadow of a dream, as it were, and perhaps actually under the influence of a special of somnambulism, Mr. Dimmesdale reached the spot where, now so long ago, Hester Prynne had lived through her first hours of public ignominy . Nathaniel Hawthorne, The Scarlet Letter, 1850.
In Hawtho rnes story, Hester Prynne underwent public humiliation at a particular spot in town. That spot was indelibly etched into the minds of the townsfolk as signifying the place of Hesters public ignominy, and it could be identified by its specific and enduring relationship to local landmarks. Familiar with these landmarks, her lover Arthur Dimmesdale knew exactly when he had arrived at the spot of Hesters public disgracing. So it is with primary directions.
P rimary directions are based almost exclusively on the movements of the planets across the sky due solely to the rotation of the Earth (diurnal motion). Except for motion of the Moon, the real motion of the planets on their orbits during the time frame under consideration is negligible.
F rom the point of view of an observer on earth, the Sun rises in the east, reaches its highest position at local noon and sets in the west, tracing a circular path or arc in the heavens (the diurnal circle of the Sun). Actually, the Earth rotates on its axis, creating the impression that the Sun and the planets move in circles around the Earth, parallel to the equator. Astrologer Vivian Robson notes that we usually speak of the Sun as moving, because to an observer on the Earth it appears to do so. The inaccuracy is in terminology only.
The same pattern of rising, peaking and setting during the course of a day is true of the planets and the degrees on the zodiac circle. Like the Sun, each planet and point on the ecliptic in the birth chart has its own diurnal circle . As the Earth continues to rotate in the hours after birth, the natal positions appear to move across the sky, eventually aligning with locations which are similarly oriented to the birth horizon and meridian. Such alignments are called primary directions. In the vernacular of 17 th century astrology, Morinus expresses this idea as follows:
directions are made by the revolution of the primum mobile , by which the promittor is transferred to the location of the significator [the primum mobile , the first moved or prime mover, is the outermost rotating sphere in Ptolemys geocentric model of the universe].
The method of primary directions is an ancient technique for identifying periods of time when the events promised in the birth chart are likely to manifest in the life of the native. The use of primary directions dates back to the 1 st century BC. Dorotheus of Sidon mentions them in his 1 st century AD text Carmen Astrologicum . Ptolemy wrote about primary directions in his 2 nd century AD Tetrabiblos where he used them to determine the length of a persons life by equating one degree of arc on the equator with one year of life.
To repeat: t he basic idea behind primary directions is that, at the moment of birth, the positions of the stars and planets in the sky around the natives birthplace mark sensitive spots on the dome of heaven (known is astronomy as the celestial sphere ). Sepharial (1923) describes these sensitive spots associated with planets as follows: the radical imprint of a planet is localized in that part of the heavens it occupied at the moment of birth; andthe radical imprint of the planet remains ever the same, and is to be regarded as entirely distinct from the planet itself, which, of course, moves along its arc in the heavens.