Skyscript Astrology Forum

Martin Gansten wrote:In the context of primary directions, the traditional usage of the terms is clear (and different from what you just wrote, Eddy):

In mundo 'in the world' or cum latitudine 'with latitude' means using the observable positions of the planets.

In zodiaco 'in the zodiac' or sine latitudine 'without latitude' means using the ecliptical (longitudinal) degrees of the planets.

Thanks for the clarification Martin. As I wrote before I indeed aren't familiar with all terminology.

Directions between planets or other points are based either on proportional semi-arcs (Ptolemy, Placidus) or on circles of position....

I believe the directions between planets most used would have been the proportional semi arc. Calculating directions according to the position circles is much more time consuming.

Hi Margherita, Martin and Eddy,

Do I understand correctly that now we have 3 uses of the term ?mundane? or Latin ?in mundo? aspects:

1) Mundane aspects in Mundane Astrology. More precisely Transit-to-Transit aspects with no Radix.

2) Mundane aspects based on the Meridian-Horizon reference frame. E.g., the Ascendant is always square the Meridian because the Horizon is always perpendicular to the Meridian.

3) ?in mundo? in Primary Directions, as opposed to ?in zodiaco?. In mundo here meaning aspects to and between the actual bodily positions in the sky. I prefer ?bodily? to ?observable? because of atmospheric refraction. ? BTW, aren?t all Primary Direction aspects mundane aspects in the sense of 2) ???

I hope I add to the confusion, but only temporarily, in order to find a common understanding.

Ren?

Martin Gansten wrote:
In mundo 'in the world' or cum latitudine 'with latitude' means using the observable positions of the planets.

In zodiaco 'in the zodiac' or sine latitudine 'without latitude' means using the ecliptical (longitudinal) degrees of the planets.

Are you telling that formula could be the same and I just can decide to use latitude or not, and in that case we have zodiacal directions? Is it like that?

If you will come in Rome, you will have a dinner out with wine from Castelli (I'm an awful cook)
Margherita

Eddy wrote:I believe the directions between planets most used would have been the proportional semi arc. Calculating directions according to the position circles is much more time consuming.

Oh, definitely, at least until there were published tables (such as those of Regiomontanus).

3D wrote:Do I understand correctly that now we have 3 uses of the term ?mundane? or Latin ?in mundo? aspects:

Well, yes and no. 'Mundane' as in the branch of astrology is a separate usage, of course. In the context of primary directions, Placidus introduced so-called mundane aspects based on proportional semi-arcs. But the older use of mundane/in mundo has nothing to do with aspects as such, only with planetary positions. Astrologers before Placidus used ordinary aspects taken along the ecliptic (or sometimes in a special 'aspect circle' close to the ecliptic, which mattered little in practice) even when directing planets in mundo.

I prefer ?bodily? to ?observable? because of atmospheric refraction.

I almost did write 'bodily' but refrained because medieval astrologers use that word of conjunctions even when taken only in the ecliptic! (This is because 'conjunction' can mean any sort of contact; thus, what we would call a trine aspect could be a 'conjunction by trine', and what we would call a conjunction by longitude would be a 'bodily conjunction'.)

BTW, aren?t all Primary Direction aspects mundane aspects in the sense of 2) ???

No; see above. As far as I know, they are a 17th century invention.

Gjiada wrote:Are you telling that formula could be the same and I just can decide to use latitude or not, and in that case we have zodiacal directions? Is it like that?

Yes, that's it: set the latitude to 0, and you have a zodiacal direction.

If you will come in Rome, you will have a dinner out with wine from Castelli (I'm an awful cook)

Thanks.

Eddy wrote:

To me it makes sense it's called "in mundo" because they consider planets as they are according their positions in houses.

Even if latitude is not taken into account it could be considered to be "in mundo". After all the same squeezing and stretching of the planetary positions occur. A trine on the ecliptic still can become a square in the mundane positions if the latitude won't be taken into account.

But that's just the kind of redefinition of accepted usage of a term that leads to confusion. There's already plenty of confusion in primary directions.

- Ed

Martin wrote:

Directions between planets or other points are based either on proportional semi-arcs (Ptolemy, Placidus) or on circles of position (Regiomontanus, though there is also a 'hybrid' form of Placidean circles of position based on semi-arcs). In neither case are primary directions based on one's choice of house system.

This statement confuses me. Various circles of position (various definitions, depending on domification model) and proportional semiarc positions give different results for directions. The domification model underlies the determination of house cusps and is conventionally called the "house system" - at least as I've encountered it when a house system has an underlying domification model. How can you say they're unrelated? Different definitions of "house system"?

- Ed

Ed F wrote:This statement confuses me. Various circles of position (various definitions, depending on domification model) and proportional semiarc positions give different results for directions.

The phrase depending on domification model rather begs the question. There are any number of house systems, but only two historically practised methods of (full-blown) primary direction; and before the 15th century there was only one in common use, namely, Ptolemy's semi-arc method (later to become the basis of the Placidus house system). Ptolemy's method was used by generations of astrologers who simultaneously employed whole-sign houses, equal houses, Porphyry houses and/or Alcabitius houses as their 'domification model'. The idea that house system and method of directions should be somehow related was apparently alien to them.

Modern authors (such as Makransky) have invented various methods of so-called primary directions based on different house systems, but these are wholly theoretical constructs and were never practised historically.

Martin Gansten wrote:

Eddy wrote:I believe the directions between planets most used would have been the proportional semi arc. Calculating directions according to the position circles is much more time consuming.

Oh, definitely, at least until there were published tables (such as those of Regiomontanus).

But can these be used to direct planets to planets? For example with a planet somewhere in the middle of house XI (Regiomontanus) and one somewhere at the beginning in house X first their positions according to that house system should be calculated and then the time it would take for the first planet to occupy the second planet's place. I don't know how this should be done with house tables alone. Perhaps the use of tables was only for the simple type of directions which calculate when a cusp will reach a certain planet.

Martin Gansten wrote:

Gjiada wrote:Are you telling that formula could be the same and I just can decide to use latitude or not, and in that case we have zodiacal directions? Is it like that?

Yes, that's it: set the latitude to 0, and you have a zodiacal direction.

Did the medieval astrologers consider them both correct or was there some disagreement? If they are both correct, is there a different meaning? It they did consider both correct it would be even more difficult to study PD's or to 'test' them.

Ed F wrote:But that's just the kind of redefinition of accepted usage of a term that leads to confusion. There's already plenty of confusion in primary directions.

I'll be more carefull in my assumptions. I didn't know before that there was a classical terminology (in mundo/in zodiaco) distiguishing the two.

Martin Gansten wrote:

Ed F wrote:This statement confuses me. Various circles of position (various definitions, depending on domification model) and proportional semiarc positions give different results for directions.

The phrase depending on domification model rather begs the question. There are any number of house systems, but only two historically practised methods of (full-blown) primary direction; and before the 15th century there was only one in common use, namely, Ptolemy's semi-arc method (later to become the basis of the Placidus house system). Ptolemy's method was used by generations of astrologers who simultaneously employed whole-sign houses, equal houses, Porphyry houses and/or Alcabitius houses as their 'domification model'. The idea that house system and method of directions should be somehow related was apparently alien to them.

Modern authors (such as Makransky) have invented various methods of so-called primary directions based on different house systems, but these are wholly theoretical constructs and were never practised historically.

That confuses me too, I don't consider it very consistent. I guess the medieval astrologers did so because it may have been considered too difficult to them to calculate proportion semi-arc houses. On the other side they could have found the direct calculating of mutual planet directions too difficult in an other method than the proportions of semi arc.

Perhaps the work of the "Modern authors (such as Makransky)" is more consistent and may be worth more investigation. Furthermore I would believe that an astrologer who uses PD's mundane should also look at the basis chart for moment zero i.e. the Radix that then could look quite different than the ecliptical Radix.

By the way, I hope the discussion hasn't drifted too far from Mark's original subject of what to do with fixed stars that are far from the ecliptic.

Eddy wrote:But can these be used to direct planets to planets?

Yes. These are not mere house tables, but Tabulae directionum profectionumque, devised with primary directions in mind. They can be viewed here:
http://digital.slub-dresden.de/sammlung ... 9002181/0/
In a circle-of-position method, an artificial horizon is devised, running through the 'static' planet, and other planets are then directed to that 'horizon' by oblique ascension.

Did the medieval astrologers consider them both correct or was there some disagreement? If they are both correct, is there a different meaning? It they did consider both correct it would be even more difficult to study PD's or to 'test' them.

Before the 15th century, directions in zodiaco were the rule. After that time opinion has been divided on the subject. Some authors consider both kinds of direction to be valid.

Ptolemy's method was used by generations of astrologers who simultaneously employed whole-sign houses, equal houses, Porphyry houses and/or Alcabitius houses as their 'domification model'. The idea that house system and method of directions should be somehow related was apparently alien to them. [...]

That confuses me too, I don't consider it very consistent.

It is inconsistent if and only if we presuppose that directions and house systems should be related. Ancient and medieval astrologers didn't, and I don't really see why they should have.

I guess the medieval astrologers did so because it may have been considered too difficult to them to calculate proportion semi-arc houses. On the other side they could have found the direct calculating of mutual planet directions too difficult in an other method than the proportions of semi arc.

Both these guesses are incorrect. Ibn Ezra described 'Placidus' houses; al-Biruni described 'Regiomontanus' directions; but neither method caught on. Don't underestimate the mathematical proficiency of the medieval authors! If they didn't do things our way, this is not necessarily because they didn't know how to.

Perhaps the work of the "Modern authors (such as Makransky)" is more consistent and may be worth more investigation.

Perhaps. Or perhaps they just need to read fewer maths books and more history books.

Martin Gansten wrote:Tabulae directionum profectionumque, devised with primary directions in mind. They can be viewed here:
http://digital.slub-dresden.de/sammlung ... 9002181/0/
In a circle-of-position method, an artificial horizon is devised, running through the 'static' planet, and other planets are then directed to that 'horizon' by oblique ascension.

Thanks for the link Martin. Unfortunately I don't read Latin but very interesting to see the ancient manuscript. I had a try with Campanus and this method came into my mind. However with this 'new' artificial horizon also a 'new' latitude of the location on Earth would been introduced. The 'horizon ' coinciding with the meridian would obviously use as latitude the Earth's equator but I didn't find a method to find the latitudes for the horizons inbetween.

Instead I first calculated the distance measured along the prime vertical (pv) of the moving and the static planet, both to the point on the horizon in the east where pv and equator meet. With as known the distance along the pv and the equatorial declination I had to find the unknown new equatorial position and for this purpose first also the 'declination'(I don't know how else to call it) measured from the pv.

This resembles the finding of the right ascension (and the latitude) of a planet when only the longitude and the declination are given (as some ephemerides do). Anyhow with many trigonometrical formulae I finally found out but perhaps the traditional method would require the same amount of trigonometry.

Quote:
........ That confuses me too, I don't consider it very consistent.

It is inconsistent if and only if we presuppose that directions and house systems should be related. Ancient and medieval astrologers didn't, and I don't really see why they should have.

Two weeks ago I had been thinking on another issue that also seemed an 'inconsistency' to me, namely the use of the division of time. (I even thought of opening a thread on this but I don't have enough time yet to 'host' a thread) If Ptolemy used the proportions of semi arcs for the primary directions and derived it from the seasonal hours which apparantly were common usage in Mediterranean (civil) life in his days then these (I reasoned) rather than the equinoctial hours should have been used in the directions. The formula should then have been 4 (seasonal time) minutes (based upon the position (declination) of the Sun in the first hours after birth, equals one year. This finally would then have been totally in line with the basis of the method of division, a Placidus type house system, proportions of semi arcs and finally the seasonal hours.

As far as I know this isn't done by anyone. So not alone say Alcabitius houses is used with Placidus proportions of semi arcs but also the time based upon equinoctial hours as the basis for the 4 minutes=1 year formula. This last element in fact reflects the Meridian house division. So it actually was a kind of 'three in one'. I'll have to think about all this, I don't feel I have to 'follow' the medieval astrologers on this. I believe I too have a problem with authority .

Don't underestimate the mathematical proficiency of the medieval authors! If they didn't do things our way, this is not necessarily because they didn't know how to.

I did tend to do so indeed. Perhaps it's because of the way how most books summarize the history of house systems. In Jim Tester's "A History of Western Astrology" it is also mentioned that the medieval astrologers/astronomers knew quite a lot about house divisions.