In the third book of Quadripartite, Ptolemy introduces something called the “extracted” chart, ie a derivate chart, which is not so stranger to Hellenistic astrology, for example in Vettius Valens. The extracted chart is nothing else than a derivative chart for “persons related to the native from his own nativity (which) are his parents, brothers, spouse, children, servants, friends.”
Anyway Ptolemy is an easy reading only for modern astrologers, who can invariably read Tetrabiblos without any difficult and doubt 🙂 Traditional astrologers on the other hand, should search here and there with pain and discomfort in order to have some insight in the midst of the convoluted language of the Alexandrian Astrologer.
Morin in his book about Directions gives a short resumé of the different explanations given by the most famous astrologers of his own age, Gerolamo Cardano and Francesco Giuntini.
The method in itself is not difficult. The astrologer could judge about the future of these persons connected with the native extracting a new chart taking:
- for the father the Sun in the day and Saturn in the night
- for the mother Venus in the day and the Moon in the night
- for the wife Venus in the day and the Moon in the night
- for the husband the Sun in the day and Mars in the night
- for brothers the tenth place from Venus in the day and the Moon in the night
- for children (and the rest I believe) “the planet which gives children (or whatever), and making his investigation of the more important questions from the rest of the configuration, as in a geniture. ” (2)
and using it as a new horoscope.
Unfortunately, the problem as almost always is the house system.
Cardano switched several systems, from Equal Houses to Regiomontanus and Alcabitius. In every case the new chart is cast for the birth place of the radix.
This is very easy to get in Solar Fire, just you can choose “Venus on the 1st” in the New Chart settings.
Let us see prince William of England’s chart and his mother
we could easily turn it in the Whole Signs House System
That’s very easy and immediate with Solar Fire, and it could be very useful when we don’t have any chart and we need desperately a sinastry!
Francesco Giuntini in his Speculum Astrologiae (3) makes us things quite difficult, because he is looking for a place to cast the chart, which is not so wrong. But if you love Primary Directions, this is your method 🙂
Giuntini completely relies on the Rational Method aka Regiomontanian way of directing.
His example is Maurice the Elector of Saxony’s chart, latitude of the birth place 51.58.
Saturn, which is the Father’s significator in a night chart is at 12.58 Aquarius.
In the same way he puts Saturn on the Ascendant, but for which place, ie which pole?
He calculates the pole (the circle of position) for Saturn which is – Giuntini says- 14.32.
Then he calculates the Oblique Ascension under the pole 14.32 which is 320.0.24. This is the new horoscope. Obviously the rest of the houses are cast in accordance, in the Regiomontanian system.
This is the same calculation with a modern software (Morinus), Saturn pole P is a little different (Placidian pole is something more than 11), W is the AO under its own pole.
So if you dont’have the chart you need now you know how to calculate a derivate one. Enjoy!
p.s. thanks to Emanuele Ciampi, Cielo e Terra secretary, who explained me another alternative method, a “mundane” method calculated according mixed ascensions and sent me a very nice spreadsheet for playing with ascensions.
(1) Morin de Villefranche, Astrologia Gallica, book 22 On Directions
(2) Ptolemy, Quadripartite, IV, 6
(3) Francesco Giuntini, Speculum Astrologiae, 1581