Ed Falis' excellent article on house system  makes us better informed, especially with regard to the Campanus system.  In this post I will attempt to add to our knowledge of houses, refering to the following: Equal, Koch, Meridian, Equal, Regiomontanus, Porphyry, Campanus, Topocentric and Placidus.  This is not a scholarly treatise, but rather a concise review with personal opinions and questions added. Comments and criticisms are welcome. 

The Equal house system was used in acient India and by Ptolemy.  Today we find it used in Britian, as it was promoted by Carter, Hone, the Faculty of Astrological Studies and The Mayo School of Astrology.  Each house is, of course, exactly 30 degrees, and it is therefore the easiest system to construct.  The equal house system supposedly reveals the essential spirit, soul, and personality of an individual.  It can be argued that this system is unscientific since the house cusps are based solely on time; the place of birth is irrelevant.  Fred Gettings (Dictionary of Astrology) states that the equal house system "is of exceedingly dubious value".Except in rare occasions, the MC / IC axis does not coincide with the 10th / 4th cusps. 

Porphyry (c. 300 A.D.)contended that the four Angles should correspond to the house cusps:  ASC=1,  DSC=7, MC=9, IC=4.  A rough and antiquated system which is no longer used today. 

The Campanus system -  revealing in psychological orientated work. 
Campanus lived in the 12th Century. 

The 8th Century Arabian astrologer ben Djabir derived the system that Placidus di Tito supposedly invented in the 17th Century.  It became widely used because of its ease of printing it in table form.  Raphael published it in 1821, and many subsequent ephemerides included these table. It remains popular to this day, probably due to its availability rather than any inherent advantageous characteristics. 

Regiomontanus  -  this is used primarily in hoary work. 

Meridian  -  evidently this is the favoured house system for Uranian astrology (is this advocated by the Hamburg school?).  One advantage is that it does not become distorted at high or low latitudes eg. for births in Scandinavia, Alaska, Singapore or Quito.  The first house cusp does not necessarily coincide with the Ascendent. 

Topocentric  -  this system relates directly to the natal latitude rather than to divisions of time.  It was first published in 1961 by Polich and Page of Buenos Aires.  British astrologers Kemp and Cornelius stated that this is the most precise house system, but the cusps are nearly identical to the Placidus system.  Tables are available for any latitude, 0 to 90 degrees. 

Koch  -  widely used in Germany, where it was devised in 1962, and other European countries.  Apparently gaining popularity elsewhere.  Not valid for high latitudes.  Especially useful for timing of events. 
 
 

Date sent:        Sun, 10 May 1998 21:53:04 -1200 

HOUSE SYSTEMS  -  BY  ED FALIS 

 You'll find advocates of many, many house systems, each swearing that 
 the one s/he uses works most effectively. 

 I use a "3D" version of Campanus for most of my natal work.  I don't 
 do much in the way of event-oriented work, which may explain my 
 preference somewhat after the explanations below. 

 My fundamental assumption is that the different frames of reference 
 used to derive the house systems each has a validity - each offers a 
 perspective or point of view on the chart.  The trick is in using 
analogical thinking about how the system is derived mathematically to 
define the perspective  you're viewing from.  This assumption is based 
on my experience and thinking  about the issue.  Your mileage may, of 
course, vary. 

 Based on this assumption, there are two kinds of house systems: 
 geometric and proportional time. 
 

STARTING POINT 

 For both geometric and proportional time systems, we start with the 
 space around the earth.  The center of this space for most systems is 
 the location  of the "event", though for some systems the center of 
the earth is used. 

We imagine this space as a sphere with infinite bounds around the 
center point. The space could also be viewed as a cubic space with x, 
y and z coordinates, but since astrological work is intimately 
interwoven with the idea of cycles, it tends to be done only in a 
spherical conceptual space. 

 Now we'll talk about geometrically derived systems, but note that all 
 systems embody the complementary derivation as a background. 
 "Space-based" systems are implicitly driven by time; "time-based" 
 systems implicitly work against a geometrical/spatial background. 
 Each heightens the perception of one element and puts the other into 
 the background.  This is why treating the systems as points of view 
 has power - any point of view reveals some aspects of a whole while 
 hiding others: it's in the nature of our attention. 
 

GEOMETRICALLY- DERIVED HOUSE SYSTEMS 

 Derivation of a geometric system starts with determining a plane 
 through the sphere to be used to make the equal divisions 
corresponding to the houses. The plane is viewed as a "great circle" 
on the surface  of our imaginary sphere, and the houses are defined 
by dividing the circumference into 12 30-degree sections.  Some of 
the planes used in various house systems are the celestial equator 
(regiomontanus), the prime vertical (campanus), the horizon 
(Zenithscope / "local space"), and the ecliptic ("equal house"). 

 Next a plane or space within which to determine a house position for 
 a body or point is selected.  In most systems, this is the ecliptic, 
 or standard zodiac.  Note that unless the measurement plane is the 
 same as the house derivation plane, the houses will have unequal 
 sizes in the measurement plane.  By analogical reasoning, the unequal 
 house systems are a bridging or  synthesis of two distinct 
perspectives (more on this later). 

 Finally, a zero-point and direction of measurement is selected.  With 
 typical house systems the zero-point is the intersection of the 
 horizon with the ecliptic (the ascendant) and the direction is 
counter-clockwise - the order of numbering the traditional/modern 
houses.  Sound arguments can be made for a clockwise measurement as 
well - see Joseph Crane's reconsideration of the lunation cycle in 
the Feb/Mar issue of The Mountain Astrologer, that gives some idea as 
to how one might apply the same approach to diurnal motion. 

 Many natally-oriented astrologers seem to prefer 
 geometrically-derived systems, though there is definitely an effect 
 of preference based on whichever table of houses happened to be 
 widespread in a given locale before the widespread availability of 
astrological software (e.g. the Placidus preference in the US). 
Michael Myer and Gordon Brown have recently written about this 
preference for Humanistic Astrology as one that provides an 
undistorted representation of personal psychological ("local") space. 
 

PROPORTIONAL-TIME SYSTEMS 

 Proportional-time systems are derived by equal division of the time 
 for a point in space to move from one geometrical divider to another. 
  The common systems (Placidus, Koch, and more obscurely, but worth 
 mentioning, the Topocentric) divide movement from the ascendant to 
 the MC, MC to descendant, descendant to IC and IC to ascendant in 
various ways.  As commonly derived, the points are points on the 
ecliptic, derived mathematically.  I believe placidus divides each of 
the quadrants defined above into equal periods of time, and looks at 
where the ascendant would be at each elapse.  I believe Koch looks at 
30 degree divisions of right ascension/sidereal time, 
measured from the RAMC and calculates ascendants for each of these to 
locate the intermediate house cusps.  The topocentric system uses a 
model based on equally dividing an "apparent cone of rotation" of the 
sky from the position of the observer.  So, each of these has an 
implicit geometric  component. 

 Some of the systems, when used for progressions and transits, take 
 into account a body's deviation from the ecliptic (celestial 
 latitude) when timing events, as seems logical; others don't. 

 I've found that astrologers working with events tend to prefer a 
 proportional-time system, as these systems are according to these 
 practitioners more effective/precise for timing events. 

 The topocentric system is interesting in that its originators based 
 its theoretical explanation on empirical timing.  The value of its 
 inductive derivation was questioned by Geoffrey Dean in Recent 
 Advances in Natal Astrology, where he pointed out that there were so 
 many potential contacts that the findings used in the derivation were 
 statistically insignificant. I found the system reasonably effective 
 when I studied it. 
 

PROBLEMS WITH APPLICABILITY OF SYSTEMS 

 Many house systems (in particular those that project or measure in 
 the ecliptic) run into problems at extreme geographic latitudes. 
 This is because there are times when the mathematical foundations of 
 their derivation fail.  For instance, the horizon can coincide with 
 the ecliptic at the arctic and antarctic circles, making it 
 impossible to define an ascendant (the point of intersection of the 
 horizon and ecliptic).  Or, for systems based on proportional 
 division of a quadrant of movement in time, a point on the ecliptic 
 may never appear above or below the horizon at certain 
 latitudes and times of year, so no basis for division of time occurs. 
  The topocentric system has a somewhat odd alternative formula for 
 dealing with this. 

 Another problem with most systems is the insistence of working on the 
 ecliptic.  All the systems mentioned so far that measure position in 
 the ecliptic place bodies depending on their zodiacal position 
 relative to the zodiacal positions of the house cusps.  This can 
 easily lead to placement of a planet with a large latitude above or 
below the ascendant/descendent axis, when the body is actually on the 
other side of the horizon (eg. pluto placed in the first house after 
it's risen).  A solution to this is center house-oriented analysis on 
the basis of position in the plane of division for geometric systems, 
and to refer to the ecliptic for synthetic information, such as sign 
relationships to the house cusps. 
 

PHILOSOPHICAL MEANINGS - WHICH HOUSE SYSTEM FOR WHAT? 

 Ok, these are my current set of opinions, based on thinking about 
 this for some time. 

 The starting point is that we exist in multidimensional space-time. 
 Choice of emphasis on time or space is nothing other than that - 
 choice.  We make distinctions to help ourselves understand and act 
 effectively.  We then elaborate these distinctions as logical systems 
 used to discover order when we apply them, or to filter what we 
 experience so we can deal with it from a given perspective.  If this 
is the nature of cognition, then different systems will work in 
different contexts, for different intents. 

 Where I find a problem is with the "one, true perspective" approach - 
 a single effective system in a context is generalized as the only way 
 to do things.  The distinction and elaboration at its foundation is 
 forgotten in its application - its context and intent are lost.  I 
 think that this effect is very prominent in the use of houses.  And 
this is why there are so many arguments over it - as we blind people 
touch the elephant, we have valid perceptions and reasoning, but we 
forget that we're blind, and are experiencing a partial perception 
intimately tied to our perspective. 

 In software development, a lot of effort has gone into modeling the 
 systems we build.  Some of the  more sophisticated practitioners have 
 come to the conclusion that our models (views on the system) can only 
 be partial - that a given system can only be well-understood by 
 cycling through multiple models using different perspectives.  A view 
 oriented towards events or behavior of a system brings some aspects 
 to attention and hides others; similarly for data (space), 
 functionality and agency (who does what) views. The whole system 
 eludes a given view because it exists at a level beyond these 
 conceptualizations. 
 

IS IT ANY DIFFERENT WITH ASTROLOGY ? 

 House systems fundamentally are trying to describe the interaction of 
 local space with more generic orbital relationships (described by 
 zodiacal positions) as mediated by the daily axial rotation of the 
 earth.  They do this through what are essentially mathematical 
 abstractions: arbitrary distinctions (with some physical 
 correlations) such as horizon, prime vertical, prime meridian, 
 zenith/nadir and paths or trails of either the physical bodies or 
 abstract mathematical points. 

 Is this anything other than a modeling system to help us understand 
 and order our experience? 

 If it is a modeling system, then the characteristics of models used 
 in software, mathematics  and systems theory are likely to apply: 
 that the reality can be captured only partially in any given model, 
 and that the meaning of phenomena in that model are driven by the 
 intent and derivation of the modeling tool.  Not to mention the 
 experience of the practitioner in correlating the abstraction with 
 phenomena. 

 In local space relative to the observer, two common measurements are 
 available: measurement by prime vertical (the foundation of Campanus) 
 and measurement along the horizon (local space directional).  One is 
 a vertical measure; the other horizontal.  These are perhaps the 
 closest frames of reference to the individual, and should measure the 
 most personal experience in these two dimensions.  Thus, Rudhyar and 
the Humanists preference for the Campanus house system for 
psycho-spiritual work (the vertical  dimension), and the use of the 
horizontal system for physical and geographical work. 

 A system like Regiomontanus, which divides the equator moves more to 
 the implicit diurnal motion perspective that is attacked more 
 explicitly by Placidus, Koch and the Topocentric approaches.  Now 
 event is the perspective we look, with varying degrees of remove 
from the spatial abstractions of the geometric systems. 

 The equal house systems, based on MC, ASC or Sun (or other body for 
 that matter) are basically casting the physical relationships of the 
 planets within the distribution of the meaning of the primary point 
 used.  A cycle is a cycle, complete with phases that cut across the 
 particular cycle being studied.  These systems measure the cycles of 
 the points or bodies mentioned in the frame of the earth's orbital 
relationship to the sun - somewhat more remote than the first two 
sets of perspectives. 

 And so on.  The orbital cycle of the earth can be viewed in the plane 
 of the ecliptic, geocentrically or heliocentrically.  Aspect 
relationships can be viewed in the ecliptic or along great circles as 
geometry, or as a phase cycle in the orbital plane of the slower 
planet.  To treat time or space in the foreground, its complement 
recedes. 

 And to further open up the wonderment, we can relate two 
 perspectives, as most house systems do, by projecting measurement in 
 one plane into another, typically the ecliptic.  The problem with 
 this is that it corresponds to our modern tradition, where we've 
forgotten that we're projecting local space or time into orbital 
space/time and often confuse the two.  So we treat a planet above the 
horizon as in the first house - we abstract a bit too far from what's 
in our faces when we go outside and look at the sky.  And we engage 
in endless debates about the relative merits of our abstractions and 
points of view, instead of communicating the true sophistication of 
this reality-modeling discipline in which we engage to the rest of 
the world. 

  Ed Falis 

On houses: my book "The Astrological Thesaurus, Book One, House Keywords," 
484 pages, 1992, Llewellyn Publications, $19.95 U.S.; contains a chapter 
called "How to Choose a House System."  In that and previous chapters I go 
to great length to explain the astronomy of house systems, as well as offer 
a logical explanation of how one can assess to use which house system when. 
 In an appendix to that book I describe twenty-three different house 
systems, and I also give the trigonometric formulae for determining any of 
these house systems.  In addition, I have a chapter in that book describing 
the astrological usage of Quadrants and Hemispheres.  The book has been out 
for over five years, and is still in print, available from local bookstores. 
 I am always amazed when I see comments from astrologers about how to choose 
a house system or what house system should one use, who obviously are not 
aware that such a resource is available, and has been available for some 
time.