Regiomontanus and Placidus

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Hello to all. I'm curious to know why many traditional astrologers use the Regiomontanus house system for horary charts, and Placidus for natal work. Lilly used Regiomontanus for both, I believe, and I've always wondered how and why this differentiation arose.

Thank you, and happy holidays!

2
Hi,

The ancients probably used whole sign house system for whatever charts.
The Greeks (e.g. Valens) did use a simple dynamic house system (called Prophyry) which simply trisect (by ecliptic) the places between angles but this house system is only used to check for strength of planets (esp. in the calculation of apheta or hyleg) and not for topical analysis.

And before you know it, different house systems were "discovered" during and after the Hellenistic period. The problem is (apart from those simple dynamic house systems e.g. equal house and Prophyry), all of these house systems require tables (the astrologers were not going to recalculate every chart - they didn't have computers or even hand calculators back then!), so I guess it was a choice based on practicallity and availability of ready made tables of houses.
Lilly used Regiomontanus for both
-Probably because he had Regiomontanus Table of Houses...?
I'm curious to know why many traditional astrologers use the Regiomontanus house system for horary charts, and Placidus for natal work.
Modern astrologers (pre-computer time) usually used Placidus because (again) Table for Placidus was available and this was the way they were taught by their teachers and their teachers before their teachers...

But when modern astrologers revived Horary (using William Lilly's books of course), they saw that he used Regiomontanus - so the modern traditional astrologers use Regiomontanus for Horary and probably still using Placidus for natal simply because they were taught that way by their teachers (who in turn were taught by their teachers who probably only had Placidus house Table during pre-computer times)

These are my guesses - of course!

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The odds are that Lilly never heard of the Placidus system as it was developed about the time of or after his retirement from astrology. Lilly, like most of his contemporaries used the Acabitius system until he was shown the Regiomontanus system and decided to go with it. Most 17th century astrologers used one or the other.

House systems will always be a thorn in the side of astrology. Each astrologer preferring this one or that one. I know I've worked with Koch, Placidus, Regiomontanus, equal and whole signs. Lately I'm fooling with Alcabitius semi-arc. To tell the truth, I think the differences are minimal. Whole signs make the most sense and are the simplest, but if the astrologer wishes to direct house cusps or direct to them, then he needs cusps to to direct to.

I think contemporary traditional astrologers use Regiomontanus for horary because they learned from Christian Astrology, and everyone else does it; and they use Placidus because it makes communication between each other simpler if everyone uses the same system. There has yet to be a definitive work indicating one system is head and shoulders above another. Opinions favoring one system over the other abound, but opinions are like noses; everyone has one. Consistency is probably more important than picking the "right" house system.

Tom

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Thank you, astrojin and Tom. I agree that the issue of house systems will always be a thorn in the collective side of astrologers. I didn't realize that Lilly used Alcabitius until he learned of Regiomontanus. When I began to study Lilly, I adopted Regiomontanus for horary charts and it worked so well that I started to use it for natal charts, as well -- with excellent results. So I wondered why modern-day traditional astrologers often switch to the Placidean system for natal work. It does make sense that Placidean puts a great many astrologers on the same page, so to speak, and offers a lexicon in common. There is something to be said for all systems, to be sure.

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I've also tried several house systems at different times, starting of course with Placidus (because of my teachers and their teachers etc.), then equal, Koch, whole signs, Porphyry, Alcabitius, whole signs, what else. Here in the Northern latitudes the differences are not always small, they can be crucial, especially when choosing between whole signs and quadrants. Finally(?) I've ended up with Regiomontanus, first because I've seen the cusps giving good results with transits (also Robert Corre, who uses Regiomontanus in all work, pointed especially to accuracy of the transits to Regio cusps, when he was giving a seminar here) and secondly, Regiomontanus is one of the few quadrant systems that doesn't collapse above the Polar Circle.

Philosophically I think that one house system should fit for all purposes.

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Hi Papretis, and thank you for your views. My experience with Regiomontanus parallels yours. I am an enormous admirer of Morinus and enjoy studying his precepts using the Regiomontanus system; my understanding is that although he developed the quadrant system that bears his name, Morinus actually used Regiomontanus in his work. So your words about Robert Corre's findings on transits are especially warmly received.

Your idea that philosophically one house system should fit all purposes speaks to what I'm getting at in this thread -- since so many traditional astrologers use Regiomontanus in their horary work, and since that system works well for natal astrology, I wonder why there is often a switch to Placidus for the latter.

It's not that I have a quibble with the Placidean (or any other) house system, I'm just puzzled as to why, since Regiomontanus cusps are sufficiently sensitive to yield accurate results in a field as house-specific as horary astrology, that same system is not widely used in traditional natal work by many astrologers who use only Regiomontanus for horary.

Again, I'm not suggesting that one house or quadrant system might be "better" than another (indeed, whole-signs houses are used successfully by many horary astrologers, often with the addition of quadrant systems for the purpose of determining planetary strength). I am simply curious about this particular Regiomontanus-Placidean switch phenomenon, and have never seen it explained.

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Astraea,

I may not be able to explain what you're curious about, but wanted to draw your attention to an interesting work by Emma Belle Donath. Her book, Houses: Which and When, makes the case for using different house systems for different purposes, contrary to the philosophical underpinnings expounded by you and Papretis. Here is a summary of her premise:

Sign-House - manner of accepting or rejecting personal karma, world conditions, and surrounding environment

Equal House - heritage from family members, genetic defects or traits, one-to-one confrontations, and closeness in relationships

Porphyry - clear division between body and soul, way of compartmentalizing spiritual and mundane matters

Campanus - immediacy of mundane conditions and how they affect society, and a timing device

Rational - cosmic views broken down into personal responses, an enhancement of the theory of "as above, so below"

Morinus - path of individual involvement into physical, mental, and spiritual matters

Placidus - goals of life, current psychological understanding, answering of horary and electional questions, and some timing

M-House - manner in which public successes or failures validate self-image

Solar Equilibrium - each house represents a facet of the incarnating ego or personality

Hamburg - Meridian = soul purpose - Ascendant = personal relationships - Node or Draconic = peer relations - Aries or Earth = world conditions - Sun = physical body and health - Moon = emotional responses

Octoscope - expectation from mundane matters of the day, and an aging device

Birthplace - past, present, and future goals, expected reactions to events and conditions

Topocentric - mundane events, timing device

She cites the Regiomontanus system by its other name, Rational. If you compare the description given there with Placidus, some of the words do support your observation, although she gives the latter to horary usage.

Let's hope that horary astrologers with plenty of experience in this subject will come out and explain this custom, if this is in fact how most of them use house systems. I don't have sufficient experience to be able to say that Regiomontanus or any other house system is accurate enough, and I've never seen any work that actually proved one system over the other. Regiomontanus, Placidus, Meridian, Eastern Point on 1st, and MC on 10th can be rationalized on technical grounds. Out of these, Placidus has an affinity with planetary hours (meaning it behaves differently in day vs night), the rest are indifferent in this respect.

Deb Houlding deals with houses in her excellent book, but she doesn't treat the division problem in detail in the first edition (perhaps she does in the second?). The first article in Michael Whackford's series on the polar horoscope (originally published in Correlation) is posted at http://www.skyscript.co.uk/polar1.html . He comes out in favour of Placidus in his earlier article originally published in The Traditional Astrologer, and posted here in its expanded version at http://www.skyscript.co.uk/placido.html , because, according to the author, it doesn't fail in polar regions. This is news to me and I'll have to read both of his articles to see if he is in fact correct in this assertion.

At any rate, this should be enough food for thought now. Hope the post raises relevant questions so that you will be able to answer your original query.
Peter

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Thank you, Aquirata. I agree that specific house systems can act as lenses through which particular dimensions of experience can be seen; and by the same token, I think that each house system on its own can act as a portal through which the astrologer can enter as many of those dimensions as his or her nature and experience allow (astrologer-as-lens).

I have never encountered a rationale for the common practice of switching from Regiomontanus to Placidus in traditional horary/natal work, and judging from the excellent responses to my question here, perhaps the issue relates more to training (as Tom suggests) than technical matters, per se. This would support Geoffrey Cornelius' idea that the astrologer catalyzes the chart, regardless of which tools he or she chooses.

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The practice you mention doesn't appear to be a rational one on the surface. Placidus is equivalent to using planetary hours (meaning that the Sun spends 1/6th of the day in each diurnal house, and 1/6th of the night in each nocturnal house), so in that sense it aligns better with horary. If I had to select a single system with the highest probability of being 'right', however, it would be Regiomontanus due to its 'rational' construction and behaviour, aligning with modern concepts.

I have read the Whackford articles. What he says in fact is not that the Placidus divisional method per se doesn't fail at polar regions but only that it can be applied above the Arctic Circle using his definition of Asc, MC, signs and houses. This may be true of other systems as well, but I haven't put my head around this problem yet.
Peter

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Hi Peter, and thank you for sharing those thoughts. I tend to stick with Regiomontanus for both horary and natal work, with results that seem reliable to me -- though I'm open to other points of view. I've only read one of the Whackford articles so far, and like you, haven't yet put my head around what he says about Placidus.

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To Papretis
Philosophically I think that one house system should fit for all purposes.
I agree.

Your statement concerning Regiomontanus is however not quite correct. Its collapse, while complete at the Poles, is already well under way in Finland. It can and will generate a normal-looking horoscope at your latitude but appearances can be deceptive. I will explain this in full in the coming months.


To Peter and Astraea
..not that the Placidus divisional method per se doesn't fail at polar regions but only that it can be applied above the Arctic Circle using his definition of Asc, MC, signs and houses.
On the contrary, I have not redefined the Ascendant, the signs, nor the houses, as has been suggested. Some qualification will be forthcoming in respect of the ?MC? and the 10th house (because culmination can occur below a circumpolar horizon) but otherwise classical definitions of all terms are adhered to throughout.

The purpose here to take first principles at their word and to then - with a little common sense - extrapolate the consequences. A redefinition of the Placidian idea will be offered but with no deviation from those principles. I have said nothing new, merely re-phrased it in non-mathematical terms, so far as that is possible.

Ideas expressed thus far - concerning the semi-arc system - stem from Ptolemy (in Almagest, not Tetrabiblos) and the observations of Otto Ludwig (1930), though I was unaware of this in 2001 when the original series commenced. Placido de Titi was of no help at all.


Mike Wackford.

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Thank you very much for this detailed reply, Mike, and please forgive me for misspelling your last name in my post (above)! I enjoyed reading your first article posted here on Skyscript, and look forward to learning more from you.