Adding/subtracting according to Ptolemy?

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In his Tetrabiblos III.10 (Robbins ed. p. 278 onwards), Ptolemy states that when the aphetes/hyleg is in the western part of the chart (between the MC and the Desc), the native will die on the direction of the hyleg to the Desc itself. However, the benefics and malefics encountered by the hyleg (whether by body or aspect) on its way there will add to or subtract from the number of years thus found. The years added or subtracted by each planet are determined by (a) its ?horary times? and (b) its own position relative to the Asc/Desc axis.

I have tried but failed to understand the exact method of calculation advocated by Ptolemy here ? he is, as Lilly put it, ?extreame short? in his writings. Nor have I found any later source explaining it. Partridge alludes to it in his Opus Reformatum, in words to the effect that neither his contemporaries nor earlier astrologers had understood the method. I did once see an example calculated by a present-day astrologer (Alessandro Barone, using the chart of Princess Diana), but that too was ?extreame short? and I have not been able to get in touch with the author.

So: is anyone on this forum familiar with these calculations, or with some secondary source discussing and explaining them? I should be very grateful for any help.

Re: Adding/subtracting according to Ptolemy?

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In his Tetrabiblos III.10 (Robbins ed. p. 278 onwards), Ptolemy states that when the aphetes/hyleg is in the western part of the chart (between the MC and the Desc), the native will die on the direction of the hyleg to the Desc itself. However, the benefics and malefics encountered by the hyleg (whether by body or aspect) on its way there will add to or subtract from the number of years thus found. The years added or subtracted by each planet are determined by (a) its ?horary times? and (b) its own position relative to the Asc/Desc axis.
Last year i tried to investigate this point too, and I asked to my friend who is one of the founder of CieloeTerra, Bezza's association, but he did not use it. So if they don't use in Cieloeterra, where they do just Ptolemy astrology...Anyway I will give a look to the article, I suppose it's one of CieloeTerra site.
Gjiada

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Thanks, Gjiada. If the article is in English, I should be glad to see it. Meanwhile, I have scrutinized Ptolemy's text and formed a somewhat clearer idea of what he means. There are similar descriptions in Valens (III.3).

The basic idea is to note the diurnal arc (in a daytime birth) or nocturnal arc (in a nighttime birth) of the planet's point of longitude in the zodiac, i.e., the amount of time (expressed in degrees of RA) it spends above or below the local horizon. One twelfth of this arc is its horary times. The planet will give or take away the same number of years if its zodiacal longitude is conjunct the Asc; the amount decreases proportionally the closer this degree comes to the Desc, where it becomes zero.

Several questions present themselves with regard to this method. One is whether Ptolemy really intended diurnal horary times to be used in a day birth, even when the planet in question is below the horizon, and vice versa. This seems rather counter-intuitive to me. A related question is whether planets already below the western horizon gradually increase the proportion of their years as they move towards the Asc, just as planets above the horizon gradually decrease theirs as they move towards the Desc. And a third question concerns what to do if the same planet should project more than one aspect (e.g., a square and a trine) to the arc of direction ? do we add/subtract its years more than once?

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Martin Gansten wrote:Thanks, Gjiada. If the article is in English, I should be glad to see it. Meanwhile, I have scrutinized Ptolemy's text and formed a somewhat clearer idea of what he means. There are similar descriptions in Valens (III.3).

The basic idea is to note the diurnal arc (in a daytime birth) or nocturnal arc (in a nighttime birth) of the planet's point of longitude in the zodiac, i.e., the amount of time (expressed in degrees of RA) it spends above or below the local horizon. One twelfth of this arc is its horary times. The planet will give or take away the same number of years if its zodiacal longitude is conjunct the Asc; the amount decreases proportionally the closer this degree comes to the Desc, where it becomes zero.
I found the article you mentioned, and it should be something like Right Distance/ Diurnal or nocturnal semiarc.
In fact at the horizon RD and DA are equal and their division is obviously 1.
For example put the Sun in Diana chart at the ascendant.
Sun at 9.04 Cancer - RA 99.87 - dec. 23.13
MC at 3.39 Pisces - RA 335.57

So RD= 99.87 (+360) -335.57= 124,30

Then DSA= Ascensional difference + 90 if declination is positive

Ascensional difference = 34,30
so DSA= 34,30+90=124,30

so Hourly distance= RD/DSA= 124,30/124,30=1

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Yes, that is a more 'mathematical' explanation of the second step than the one I gave. (I assume that by Right Distance you mean meridian distance.) The first step is finding the horary times of the planet (or, more correctly, of its zodiacal degree).

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I discussed a little the subjiect with my friend in CieloeTerra.
I believe we could just take temporal hours of the planet and multiply it for hourly distance (to the DESC)/12.

If you play a little with algebra you will see that at the end you will have RD/DA.

In this case, as you mentioned, for a planet below the horizon, I agree we should use night hours.

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Gjiada wrote:I believe we could just take temporal hours of the planet and multiply it for hourly distance (to the DESC)/12.

If you play a little with algebra you will see that at the end you will have RD/DA.
I am not sure I follow you. If by RD you mean what is usually called MD (meridian distance), then that relates to a planet's semi-arc, not the full diurnal (or nocturnal) arc. The full arc comprises 12 'horary times'; the semi-arc, 6.

If by 'temporal hour' you mean the same as 'horary times' (HT=DA/12 or DSA/6), then I agree that Ptolemy seems to advocate taking the full HT (if you like, HT*12/12) for a planet on the Asc, and using proportions in other cases (e.g., HT*6/12 for a planet on the Midheaven).

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steven wrote:Hi Martin,

This is probably a stupid question, but why would we use 12 in order to find the horary times? For Ptolemy's location this is roughly true. However when you move above the tropics into higher (or lower) latitudes 12 would only be true at the spring and autumn equinoxes and the closer we move to the solstices the greater the diurnal or nocturnal horary times would be. Since you live in Scandinavia, you are acutely aware of the fact that after the spring equinox the horary times increase dramatically for the diurnal arc. Right now where we live, the temperoal diurnal hours are considerably greater than 12! Should we not divide rather by the true temporal hours?

Steven
It's me that wrote 12, because I was taking into consideration planets aspecting Hyleg from above horizon.

In this case we shoud calculate hourly distances not to the nearest angle but to the Descendant, because we are talking about the case Hyleg is in the second quadrant, from MC to DESC.
Then because we should add or subtract in proportion of the position of the aspecting planet we should divide this hourly distance by 12, that is 6 hours of the first quadrant and 6 hours of the second one.

If the aspecting planet is at the Ascendant it will be at 12 hours from Desc, but if at 2.3 from MC for example, it will be 2.3+6=8,3 from Descendant, so we should consider the proportion to subtract if a malefic or to add if a benefic as Ptolemy writes.

Anyway I believe they did not use this method not even in CieloeTerra.
Last edited by margherita on Tue Aug 05, 2008 5:52 pm, edited 1 time in total.

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I am not sure I follow you. If by RD you mean what is usually called MD (meridian distance), then that relates to a planet's semi-arc, not the full diurnal (or nocturnal) arc. The full arc comprises 12 'horary times'; the semi-arc, 6.
It's just because i gave you the formula already divided by 12:

In fact
DH= 6*DR/SAD

DH/12 = 6*DR/(SAD*12)
DH/12= DR/2SAD
DH/12= DR/AD

If by 'temporal hour' you mean the same as 'horary times' (HT=DA/12 or DSA/6), then I agree that Ptolemy seems to advocate taking the full HT (if you like, HT*12/12) for a planet on the Asc, and using proportions in other cases (e.g., HT*6/12 for a planet on the Midheaven).
I agree with you

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English isn?t my strong page,but theme is interesting.I?m two years ago references to him cast aside and returned to studying primary directions.
Used sources:

Ptolemys Tetrabiblos or Quadripartiete,J.M.Ashmand-includes appendix from Almagest relating to chapter "Of the Length of Life".

Tetrabiblos Book III,Project Hindsight,Robert Schmidt-includes appendix on Ptolemy? primary directions technique by Robert Hand.

Hephaistio of Thebes,Compendium Bk.II,Project Hindsight-examples.

Antonius de Montulmo,On the Jugment of Nativities,Part 2,Project Hindsight.

Bulletin of Research,Vol.1,Sep.2006,Varna,Bulgaria-Gauricus&HenryII-Medieval Astrological Prognosis,Rumen Kolev-Kolev explication directions in the ordner of the signs and against the order of the signs.

Zoller and the Alcabitius primary direction method,Rumen Kolev-Kolev verification about equality -Zoller=Alcabitius=Placidus Semi-Arc=Ptolemy primary directions.

Correspondence between Alessandro Barone and Dr.Gonzago Pena Tamez-I_predict

Text - Princess Diana? death:classical prediction,Alessandro Barone(AB)

I?m attempted as Martin about reconstruction procedure AB.Attempt wasn?t too successful.

Begin so step by step again.
Princess Diana Natal Chart: 1 Jul 1961,7:45 PM
GMD -01,Sandringham,England ,0e30'00,52n50'00

Hyleg-Pars Fortunae

Hyleg setting time designates AB = +42d25m.

Seting time is given (Hyleg between MC and DSC),zodiacal primary direction Pars Fortunae and DSC.Matches it birth 7:44 PM.
First question on to other procedure is,whether planets were to by calculation with latitude or as with Ptolemy without latitude?

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Ed F wrote:If Alessandro did it, it would not include latitude - he used the ecliptic intercepts.
To the best of my knowledge, so did Ptolemy, and all ancient and medieval astrologers up to the 15th century. Latitude was used to modify interpretations, not calculation of directional arcs.

I did once see AB's calculation example, but could not follow it. I also doubt that Ptolemy would have accepted the PoF as apheta/hyleg in the chart given. He seems (for this purpose at least) to have advocated an 'equal house' system, which would make the Sun the apheta.