Re: Ptolemaic aspects exclusive of house type

2
varuna2 wrote:
Is this adjustment of Ptolemaic aspects to match the ratio of both the size of, and placement within, a house in an unequal house system, a method of delineation used by those who use unequal houses?
For what I understood of your example- I'm not sure I caught it, you are talking about mundane aspects.

In this case aspects are not taken by longitude but in respect to the Placidian house. Two planets which are in the middle of the house, the one in the first and the other in the third are in sextile whatever longitude they have.

Take care that in mundane aspects planets keep their latitude, they are not projected on the ecliptic. Surely Martin Gansten can say more,
margherita
Traditional astrology at
http://heavenastrolabe.wordpress.com

3
Varuna 2 wrote:
For those who use Ptolemaic aspects, do you use them irrespective of the house type?
I would say this is more a question about our attitude to out of sign aspects (and the orbs used) or mundane aspects than really what house system is utilised. In terms of out of sign aspects some astrolgers use these and others dont. I think there are three basic approaches to aspects in western traditional astrology:

1 By whole sign ptolemaic relationship
2 By degree only (allowing out of sign aspects)
3 By mundane aspect.

1 By whole sign ptolemaic relationship

I'm afraid I find your example a little confusing. But lets assume we have Mars at 28 Aries and Saturn at say 28 Cancer. Astrologers using both WS and quadrant houses would find a zodiacal square here regardless of house system.

2 By degree only (allowing out of sign aspects)

However, say we have the Moon at 29 Aquarius and the Sun at 2 Scorpio. In terms of whole signs these planets are in square. However, by degrees we have an out of sign trine between the Moon and Sun here. Many western astrologers would still count such an out of sign aspect.

There may be some support for out of sign aspects in ancient astrology. They certainly considered conjunctions across the sign boundary within 3 degrees. Some may also have considered other aspects across sign boundary too.

Otherwise why does the 1st century CE Roman astrologer Manilius state the following?
"And though a man compute a fourth sign from a fourth, the degrees in themselves will cause the wreck of a whole sign. It is therefore not enough to count trigons by signs or to expect a true square from signs at intervals at four". Astronomica, Manilius (2.305-340)
3 By mundane aspect.

In other words allowing for the fact that the tropical signs rise at different times. In general terms they can be divided into signs of long or short ascension. Ptolemy himself mentions this issue in regards to aspects:
?And sometimes, also, among the signs that ascend slowly the sextile aspect destroys, when it is afflicted, and again among the signs that ascend rapidly, the trine?. Claudius Ptolemy, Tetrabiblos (p. 283, Loeb edition)
Hence Ptolemy is clearly suggesting with two planets in signs of long (or slow) ascension a sextile aspect is effectively 'stretched' and operates more like a square while in signs of short (or fast) ascension a trine is effectively 'shrunk' and therefore operates more like a square.

The point is about the nature of the tropical signs themselves not the house system utilised.

Here is more information on the subject:

http://www.projecthindsight.com/images/ ... nTimes.pdf

http://skyscript.co.uk/forums/viewtopic.php?t=1742

http://tonylouis.wordpress.com/2012/01/ ... t-a-trine/

Mark
As thou conversest with the heavens, so instruct and inform thy minde according to the image of Divinity William Lilly

4
Mark wrote: The point is about the nature of the tropical signs themselves not the house system utilised.
Mark
Perhaps your statement is true if one only considers mundane aspects in the context of the ascension times of signs. But mundane aspects can be determined by degree with no reference whatsoever to ecliptic coordinates. The geometry of the house system used (provided is has a concept of mundane position) will be the determining factor.

Unless you don't believe in aspects based only on degree relationships, and require sign relationships for them.

- Ed

6
Ed F wrote:
Perhaps your statement is true if one only considers mundane aspects in the context of the ascension times of signs.
Yes I am not aware there is any evidence of any other method but ascensions in ancient and medieval astrology. Of course supporters of Placidus houses usually point out that their semi-arcs can be used to derive mundane positions of planets. Due to the similarity to Ptolemy's system of primary directions its often argued he might have advocated this approach to aspects but the evidence seems scant to support this. As I understand it Placido De Tito was the first to propose Ptolemy's proportional semi-arcs as a system to calculate mundane aspects while Maginus proposed aspects in right ascension.

A previous thread picked this issue up and Martin Gansten's comments are very informative.

http://www.skyscript.co.uk/forums/viewt ... a4a8b6b577

Ed F wrote:
But mundane aspects can be determined by degree with no reference whatsoever to ecliptic coordinates.
I concede my comment was misleading since late renaissance and modern astrologers have developed other methods of calculating mundane aspects that are non-zodiacal and indeed non-ecliptical.

Still irrespective of house system used there appears to be only three methods of calculating mundane aspects:

a) ascensional rising times
b) proportional semi-arcs
c) positions by right ascension

Are there others?

Ed F wrote:
The geometry of the house system used (provided is has a concept of mundane position) will be the determining factor.
So what house systems are we actually referring to?

I assume you mean time based house systems utilising semi-arcs such as Placidus, Alcabitius and Koch?

Mark
As thou conversest with the heavens, so instruct and inform thy minde according to the image of Divinity William Lilly

7
Mark wrote: Of course supporters of Placidus houses usually point out that their semi-arcs can be used to derive mundane positions of planets. Due to the similarity to Ptolemy's system of primary directions its often argued he might have advocated this approach to aspects but the evidence seems scant to support this.


It's obvious that Placido built his house system on Tetr, III, 11. If Ptolemy used or not Placidean houses is not so important, but it's true that semiarc directions fit very well with Placidean houses, because if I should direct a planet by hand (without using a software) I should always know where is that planet in the Placidian house.

I know that Martin says that directions are not connected with house system, and it is true in theory, but in practice directing Regiomontanus and using Placidus and viceversa it makes no sense
Still irrespective of house system used there appears to be only three methods of calculating mundane aspects:

a) ascensional rising times
b) proportional semi-arcs
c) positions by right ascension
It was Varuna who mentioned the position of a planet in a house, and his example evidently fits with the Placidian mundane aspect where aspects are taken according the houses (still Placidian mundane aspects have latitude).

Try to cast the chart with Morinus and you will see that zodiacal directions form the aspect by longitude (even when they have latitude- at least I use the significator with its latitude), but not the mundane aspects, they form the aspect in the (Placidean) house, not by longitude

Try and let me know,
margherita
Traditional astrology at
http://heavenastrolabe.wordpress.com

9
margherita wrote:I know that Martin says that directions are not connected with house system, and it is true in theory, but in practice directing Regiomontanus and using Placidus and viceversa it makes no sense.
Whyever not?

Throughout the Middle Ages most astrologers seem to have used semi-arc ('Placidean') directions and Alcabitius houses. It appears to have made sense to them. (I know your example said Regiomantanus, not Alcabitius, but I don't know whether, historically, the Regiomontanus/'rational' house system was ever used together with semi-arc directions. The point is that it is perfectly possible to base domification and directions on different principles.)
https://astrology.martingansten.com/

10
Varuna 2 wrote:
Margherita posted again mentioning the Placidian use of mundane aspects, which I will assume to be valid with Polich-Page as well.
Good question. We clearly need Ed's or Martin's input on this. :)

Although the house system of Polich-Page (Topocentric) yields very similar results to Placidus (usually about 1 degree difference) and is described as a time based house system I understand the mathematical differences are quite fundamental. Indeed I have seen Topocentric described as incorporating a time, space and equatorial element. :???:

http://www.levante.org/domification/topocentre1.html

I am afraid the maths is way beyond my limited ability.

Mark
Last edited by Mark on Sun Apr 01, 2012 7:34 pm, edited 2 times in total.
As thou conversest with the heavens, so instruct and inform thy minde according to the image of Divinity William Lilly

11
Varuna: the confusion stems from the non-rigorous use of the term 'mundane aspect' to signify any type of angle not calculated in the ecliptic. As Mark pointed out, there are several varieties, including angles in right ascension, oblique ascension and proportional semi-arcs. Historically speaking, the term 'mundane aspect' is most properly used of the semi-arc variety, devised by Placidus. (There are also theoretical systems of 'mundane aspects' formulated in analogy with house systems other than the Placidean, but never used historically, to my knowledge.)
https://astrology.martingansten.com/

12
Martin Gansten wrote:
The point is that it is perfectly possible to base domification and directions on different principles.
Yes. In addition I think its perfectly possible to use placidean mundane aspects as a self standing technique without feeling the need to adopt placidus houses for natal work. I personally, use whole sign houses for nativities but still find mundane aspects by proportional semi-arcs useful. As this is a non-zodiacal technique it can be equally applied by tropical and sidereal astrologers.

If I am reading him correctly the western siderealist Ken Bowser seems to advocate a form of mundane aspects based on right ascension:

http://www.westernsiderealastrology.com ... _mundo.pdf

Mark
As thou conversest with the heavens, so instruct and inform thy minde according to the image of Divinity William Lilly