Directing according Valens and Ptolemy: ascensional times against semiarc

In this short post I’ d like to compare the main methods of directing in Hellenistic astrology. Many have already explained this subject (( see for example  Martin Gansten, in Balbillus and aphesis in Greek, Roman, and Byzantine Studies, n. 52 (2012) )) but it can be useful to recapitulate the matter.

Ptolemy does not use the Hellenistic method but a method  which it is differentiated according the position of the point.

He says:

However, the number of years, determined by the distances between the prorogative place and the destructive planet, ought not to be taken simply or offhand, in accordance with the usual traditions, from the times of ascension of each degree, except only when the eastern horizon itself is the prorogator, or some one of the planets that are rising in that region…..Whenever the prorogative and preceding place is actually on the eastern horizon, we should take the times of ascension of the degrees up to the meeting place; …..But when it is actually at the mid-heaven, we should take the ascensions on the right sphere in which the segment in each case passes mid-heaven; and when it is on the western horizon, the number in which each of the degrees of the interval descends, that is, the number in which those directly opposite them ascend. But if the precedent place is not on these three limits but in the intervals between them, in that case the times of the aforesaid ascensions, descensions, or culminations will not carry the following places to the places of the preceding, but the periods will be different. (( Ptolemy. Tetrabiblos. Translation Frank Robbins. Cambridge  Mass.  ;London: Harvard University Press ;; W. Heinemann, 1980. ))

And following he puts some examples where he mentions two variables: the position of the point in the quadrant and its speed; so in order to calculate the direction we will measure the distance of the two points in the sphaera and move the point which follows to the point which precedes according the speed of the former.

The Hellenistic method is easier and it is based on the ascensional times in whatever part the point is situated.
Let us see a couple of examples.

First example from Vettius Valens (( Anth, III, page 60 Riley translation, thanks to Ile Spasev ))

example from Vettius Valens
example from Vettius Valens

An example: let the Ascendant be Sagittarius 18°, MC Libra 4°, and the houseruler Mercury at  <Scorpio> 13°.  ….
Having established this, now let the moon be the apheta at Libra 8°. For the remaining 22° <of Libra> I assign 29 years 4 months; for the 30° of Scorpio, 36 years; and for the 17° of Sagittarius, 18 years 1 month 18 days. Added, the total of the vital sector is 83 years 5 months 18 days.

Calculation is very easy. From the Ascendant to the Moon we will have 83.46, corresponding to 83 years, 5 months, 17 days. In fact:
-for the 17 degrees of the Ascendant, considering that 30 degrees of Sagittarius ascend in 32 times, we will have 17 *(32/30) = 18.13
– for the 30 degrees of Scorpio 36 times
– for 22 degrees of Libra, which ascends in 40 degrees, we will have 22*(40/30) = 29.33

Second example from Paulus of Alexandria, (( Paulus Alexandrinus and Olimpyodorus with the Scholia from Later Commentators, cura Dorian Greenbaum, Arhat, 2002  ))

Paulus example
Paulus example

Differently from the first example here the Ascendant is not involved still Paulus still considers ascensional times.

For example. The Sun in the 15th degree of Scorpio, Ares in the 23th degree of Leo,  the Moon in the 6th degree of Sagittarius, the Horoskopus in the 21th  degree of Scorpio. We will consider first the circumambulation of the Sun and the degree contact it makes by meeting with Ares and the Moon. In addition to these, [we will consider] the circumambulation of the Horoskopos, and the contact which the Moon makes from a meeting either with the Sun or with the |star| of Ares. First we will begin from the solar circumambulation.  Since the Sun is in the 15th  degree, it rises for the Egyptians in the zone of Alexandria through 35 years. I apportion the 35 years among the 30 degrees of Scorpio and the one which rises in the same time, I mean of course Leo, and I find 4 months for the degree of Scorpio and Leo. The Sun is at the 15″’ degree, Ares at the 23’“ degree of Leo. The remainder from the Sun to the place of Ares is 8 degrees. I do eight times 14,  which gives 112 months, which equals 9 years and 4 months.

We should direct the Sun to Mars opposition. The Sun is at at 15 Scorpio, Mars at 23 Leo, so the Sun should reach 23 Scorpio, which are 8 degrees. As in the example above we have, considering that Scorpio ascends in Alexandria in 35 times: 8*(35/30) equal 9.33, corresponding to 9 years and 4 months (in the example Paulus makes his example in months multiplying by 12 and then converts in years).

So as we see the two methods are very different:  depending on the position and on the very point which moves Ptolemy’s one,  steady in the result wherever the point we move is, the Hellenistic one.


a short guide to primary directions

ptolemy and placidus directions

the hellenistic/vedic case for ascensions


Written by Margherita Fiorello, CIDA certified member, for heaven astrolabe blog @ year 2013. If you want to be notified the next time I write something, subscribe to my RSS feed.



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