Skyscript Astrology Forum

Hi there,

what is the difference between:

1. Mundane primary directions
2. Zodiacal primary directions with significator and promissor latitude

Both methods do have the same hit dates for directions to planet bodies (cunjunction aspects). But if aspects > 0 are involved both methods differ.

Why is that? What is the difference between both methods?

Regards,
Chris

The reason for the difference is that the so-called mundane aspects invented by Placidus are not based on separation by ecliptical longitude, but on proportions of a planet's diurnal motion. Say that, in a chart, Jupiter has travelled exactly 1/3 of the way from the MC to the Desc (which would put it on the 9th Placidus cusp), and the sun is somewhere in the first house (below the horizon). When the sun reaches the horizon/Asc, it would then be considered to form a 'mundane trine' with Jupiter, because every 1/3 of a quadrant in a planet's motion equals 30 'mundane degrees'. So 3x30 from the Asc up to the MC + another 30 = 120, or a trine. This is true even if Jupiter is actually around 90 degrees of longitude from the Asc, or 150 degrees or whatever.

The more traditional methods use aspect points taken in the ecliptic, or (if latitude is assigned to the aspects) in a special aspect circle close to the ecliptic. So long as the opposition is assigned the opposite latitude to the planet itself (i.e., northern if the planet is southern and vice versa), conjunctions and oppositions will be the same in both systems, but the other aspects may vary quite considerably.

Martin thank you for your clear explanation.

So mundan aspects can also be measured in a birth chart itself.

Lets have a look at a birth chart:

1. First it's calculated with planets without latitude (as we usually do).
2. Then it's calculated with planets including their latitudes.
(The planet positions are projected to the ecliptic including their latitudes).

For both birth charts we can measure the mundan aspects between its planets. The same as we can measure its planet aspects on the ecliptic excluding and including planet latitudes.

So I wonder why astrology programs usually don't have latitude options for mundane primary directions the same as they provide them for zodiacal primary directions? So why are mundan primary directions always calculated including planet latitudes?

Chris Meyer wrote:So mundan aspects can also be measured in a birth chart itself.

They can, though I'm not sure if Placidus himself advocated that. But the angles, for instances, are by definition always configured by mundane square, so any planet right on the Asc/Desc would form a mundane square with any planet on the MC/IC.

Lets have a look at a birth chart:

1. First it's calculated with planets without latitude (as we usually do).
2. Then it's calculated with planets including their latitudes.
(The planet positions are projected to the ecliptic including their latitudes).

Not quite sure how you envisage this. When you project the actual position of a planet (i.e., including latitude) onto the ecliptic, what you get is the position without latitude that is typically used in astrology.

For both birth charts we can measure the mundan aspects between its planets. The same as we can measure its planet aspects on the ecliptic excluding and including planet latitudes.

Again, I'm not entirely sure how you mean. If you want to measure 'ordinary' aspects between planets with latitude, to the degree and minute, you will have to construct a special circle that is slightly inclined to the ecliptic and take the measurements from that. So they wouldn't strictly speaking be ecliptical aspects.

As for mundane aspects without latitude, that is, between points in the ecliptic: yes, that could certainly be done, but I don't know of anyone who has propounded such a method.

So I wonder why astrology programs usually don't have latitude options for mundane primary directions the same as they provide them for zodiacal primary directions? So why are mundan primary directions always calculated including planet latitudes?

I suppose the simple answer is because Placidus invented the method, and he only ever used it for the actual bodies of the planets, not for their ecliptical projections.

Martin Gansten wrote:Not quite sure how you envisage this. When you project the actual position of a planet (i.e., including latitude) onto the ecliptic, what you get is the position without latitude that is typically used in astrology.

I'll try to show what I mean with a example birth chart of Prince Charles:
https://www.astro.com/astro-databank/Ch ... e_of_Wales

The first chart is calculated without planet latitudes. (A standard birth chart we normally using): The second one is calculated including planet latitudes: Pluto differs most because of its high latitude. Pluto without latitude (first chart) is placed in the second third of the first house. Whereas Pluto including its latitude (second chart) is placed in the first third of the first house.

One can calculate birth charts including planet latitudes with the astrology program "Morinus" via primary direction calculation and the option to include planet latitudes. To get the birth chart as result primary directions have to be calculated for the exact date and time of birth.

I don't know if the second chart including planet latitudes is technical 100% correct. But for measuring planetary aspects of zodiacal primary directions including planet latitudes it works. Based on this chart and its planet positions the planet aspects can be exactly measured. In general I think any 2D presentation of the real 3D earth space will lack in some way anyway.

So now we have two zodiacal birth charts one without and the second one including planet latitudes. Based of the data of these two zodiacal charts it is very easy to calculate their two mundane counterparts. Just draw a 360° circle with 30° houses and place the planets relating to their house positions.

Here for example is the mundane version including planet latitudes, the mundane counterpart of chart two (Pluto is placed in the first third of house one): In the mundane chart we now can find an exact Mars/Saturn square aspect between the 2. and 5. house (the 5. house symbolizes amongst other things romance and love affairs). Because Mars is the ruler of his tenth house. It doesn't wonder that Charles is widely known for his deep conflicts relating to a love affair. So we can find some truth in his mundane chart.

This Mars/Saturn square aspect isn't there in his zodiacal chart. Only if you use whole sign houses in the zodiacal chart there's a chance to allow this aspect to be legit. But the exact square of the mundane chart speaks so much clearer about the high importance of this aspect.

I can't show here the mundane counterpart of the normal birth chart without planet latitudes, because "Morinus" doesn't have this option. But the main difference is pluto as said before. The exact Mars/Saturn square is the same.

Now I'm able to say what I'm initally wanted to say: Generally speaking I think mundane charts and mundane primary directions without planet latitudes are the same legit as the ones including planet latitudes. Therefore I don't understand why they are not supported in astrology programs that calculate primary directions like "Morinus" or "Janus" for example.

Martin Gansten wrote: As for mundane aspects without latitude, that is, between points in the ecliptic: yes, that could certainly be done, but I don't know of anyone who has propounded such a method.
...
I suppose the simple answer is because Placidus invented the method, and he only ever used it for the actual bodies of the planets, not for their ecliptical projections.

Thank you Martin for confirming that generally there is nothing that speaks against mundane aspects without latitude.

Chris Meyer wrote:One can calculate birth charts including planet latitudes with the astrology program "Morinus" via primary direction calculation and the option to include planet latitudes. To get the birth chart as result primary directions have to be calculated for the exact date and time of birth.
[...]
So now we have two zodiacal birth charts one without and the second one including planet latitudes.

No, that's not the difference between the two charts. (I was peripherally involved in the process of designing that feature of Morinus, so I know it well.)

A standard astrological chart shows the longitudes of the planets, that is, their projections onto the ecliptic by a line (well, circle, really) perpendicular to the ecliptic. The Morinus PD chart you refer to shows not longitudes, but something more akin to co-risings: if you set the date to the birth date and include latitude, it will display the degree and minute of the ecliptic that was at the same point in its semi-arc as the planet at the time of birth -- for instance, exactly 89% of the way between rising and culminating, or what have you. Both charts are based on the actual bodies of the planets; they are just connected to the ecliptic in two different ways. I suppose you could call it a spatial versus a temporal projection.

(This is presuming that you are using the semi-arc method of primary directions. If you are using position circles, it will be a matter of two different spatial projections. But it is still the case that we start from the real bodies of the planets and then look for 'corresponding' points in the ecliptic. What that feature of Morinus is really meant to do is to find the directed position in the zodiac of any point on any date, which is very useful for judging transits, etc.)

Martin Gansten wrote:A standard astrological chart shows the longitudes of the planets, that is, their projections onto the ecliptic by a line (well, circle, really) perpendicular to the ecliptic. The Morinus PD chart you refer to shows not longitudes, but something more akin to co-risings: if you set the date to the birth date and include latitude, it will display the degree and minute of the ecliptic that was at the same point in its semi-arc as the planet at the time of birth -- for instance, exactly 89% of the way between rising and culminating, or what have you. Both charts are based on the actual bodies of the planets; they are just connected to the ecliptic in two different ways. I suppose you could call it a spatial versus a temporal projection.

Martin, thank you for making clear what the Morinus charts (including latitude) are actually showing. I wasn't fully aware of its technical background.

So I was wrong in my first post to call these charts a projection of planet bodies including their latitudes on the ecliptic. If I understand you correct they are more a projection of planet bodies including their latitudes to its (Placidus) house position.

I came to the wrong conclusion because if I interpreted the shown planet values of these charts as planet longitudes I was able to measure with these values correct primary direction aspects to the planet longitudes of the birth chart (if I remember correct: aspects of promittors to significators).

That leads me to my last question:

Why are following options are grayed out in the astrology programs Morinus and Janus if mundane primary directions are selected:

1. "Aspects of Promittor to Significator"
2. "Promittor to Aspects of Significator"

Are these options not relevant for mundane primary directions? Or why is that?

Chris Meyer wrote:Why are following options are grayed out in the astrology programs Morinus and Janus if mundane primary directions are selected:

1. "Aspects of Promittor to Significator"
2. "Promittor to Aspects of Significator"

Are these options not relevant for mundane primary directions? Or why is that?

It is precisely because mundane aspects are not concerned with aspect points (in the ecliptic or any other circle), but only with proportions of motion. If by promissor we mean the planet that is being moved with the primary motion (which is a misuse of the term, but almost universal today), then all mundane aspects must be formed by the motion of the promissor -- there can be no alternative.

In the traditional setup, if you have the sun at 5 Aries and Jupiter at 20 Sagittarius, then Jupiter casts a trine into 20 Aries, and the sun casts a trine into 5 Sagittarius, and both aspect points can be used to effect a contact between the two planets, at slightly different times. (The two directions would not typically be considered equally important, but that's another matter.)

Maybe , Rapt parallels in mundane would be the time when two planets are moved together to an equidistant position from AAC/desc.

Thank you Martin.

pankajdubey wrote:Maybe , Rapt parallels in mundane would be the time when two planets are moved together to an equidistant position from AAC/desc.

Yes, or from the MC/IC (the meridian). Rapt motion (another invention of Placidus') thus constitutes a third category in addition to the traditional direct and converse motion. (But all these 'motions' are still based on a single real motion, namely, the primary motion, with everything moving clockwise around the sky -- at least as long as you are in the northern hemisphere.)