HOUSE SYSTEMS: Differences Between Them

An Information Special from Astro Communications Services

House systems are methods of dividing the sphere into 12
parts. Quite a lot of controversy exists among astrologers as
to which of several methods “works” the best — or if,
indeed, any of them work! (The latter point of view is
generally held among Cosmobiologists, who study charts
primarily on a 90° dial which ignores house positions
entirely.


Placidus
The majority of astrologers in the English-speaking world
use the Placidus house system, but this is not because it has
been “proven” best, but rather because the Placidus system
was the first one to be widely published and therefore got
the inside track. It was invented in the 17th century by an
Italian monk, Placidus de Titus, and became popular in
English-speaking countries with the annual publication of
Raphael’s Almanac, which included Placidian tables. Books
that include Placidus house tables are still the most easily
and inexpensively available in most places. Therefore they
have been widely used over the years by astrology teachers
who, of course, tell their students to use them, thus perpetuating
their popularity.
Some astrologers would disagree with the observation
that the Placidus system is unproven, because the Gauquelin
research (one of astrology’s only claims to statistical
proof) puts forth sectors that are closely akin to Placidian
houses. This is undoubtedly a point in favor of Placidus, but
nevertheless, we dare say that the majority of people use
Placidus houses merely because of our first reason given
above, rather than the latter.
In the Placidus system the house cusp curves are formed
by points each of which trisects its own diurnal or nocturnal
semi-arc. If you are not familiar with spherical astronomy,
that definition is probably, shall we say, less than clear, but
a detailed description of this complex exercise in mathematics
is beyond the scope of this Information Special. For
now, important facts to point out are:
1. It is an unequal house system, resulting in interceptions
in some locations (see also Information Special
IIHX — Intercepted Signs: Why All Houses Aren’t
Equal);
2. The Midheaven is the cusp of the 10th house and the
Ascendant is the cusp of the first house;
3. The system gets very weird near the polar regions —
over half the zodiac signs can be intercepted (not
appearing on any cusp); and finally (but very important
that you know)
4. The Placidus system is Astro’s computer default —
if you don’t specifically request an alternate system
when you order, Placidus is what you will get!
(Majority rules.)

Campanus
This system divides the prime vertical into 12 equal arcs by
lunes whose poles are the north and south points of the
horizon. The house cusps are the degrees at which the lunes
intersect the ecliptic. As with other unequal house systems,
there is extreme distortion at birthplaces far from the equator.
Two brothers, Joseph and Matthew Campanus, who
lived in the late 15th century, may have originated this
system, but it is also possible that it dates back to the 13th
century. This system has had strong support from a number
of famous astrologers; notably, Dane Rudhyar and Charles
Jayne.
Regiomontanus
Here we have the celestial equator divided into 12 equal
segments beginning at the East Point, and lines perpendicular
to the prime vertical drawn through the points of division
and projected onto the ecliptic as house cusps. This system
is identical to Campanus for birthplaces on the equator, and
like Campanus it gets extremely distorted in the polar
regions. It was invented in the 15th century by a German
astronomer whose name, of course, was Regiomontanus.
Alcabitius
This one dates back to at least the 1st century AD, and is the
one used in the few surviving examples of Greek horoscopes.
The Ascendant is the first house cusp, and from
there house cusps are determined by means of trisecting the
diurnal semi-arc. A point in favor of this system is that even
though it is unequal, it does not fall apart in polar regions.
But at certain birthtimes, there can be a large variation in
house size, no matter what the latitude.

Porphyry
Attributed to a Neoplatonist named, of course, Porphyry,
this system dates from the 3rd century AD. The Midheaven
is the cusp of the 10th, the Ascendant is the cusp of the 1st,
and intermediate houses divide each quadrant equally as
measured on the ecliptic. As with many of the others, you
get very strange distortions in polar regions.

Topocentric
This one is considerably different in that it was derived
empirically, rather than from mathematical theory. Its theoretical
basis was formulated after empirical evidence for
house cusps was gathered through the study of primary
directions. It was introduced in the 20th century by two
Argentine astrologers, Wendel Polich and Anthony Nelson
Page. Its cosmography is topocentric rather than geocentric,
meaning that the birthplace remains on the surface of the
Earth, rather than being projected to the center in order to
take advantage of the great circles of the celestial sphere. It
is interesting that although the mathematical basis for this

Koch
In the Koch system only the diurnal semi-arc of the MC is
trisected. The MC is then rotated backwards through its
diurnal semi-arc to the horizon to determine the 11th house
cusp, and then again to determine the 12th and so on. The
Koch system (first published, though not invented, by Dr.
Walter Koch, 1895-1970) originated in Germany, home of
the Uranian and Cosmobiology schools, so if a Cosmobiologist
looks at houses at all, they will no doubt be drawn in the
Koch system. This is the next most popular system after
Placidus, and is the choice of this author (whose technical
specialty is Uranian/Cosmobiology) not because anyone
has satisfactorily proven its superiority to me, but merely
because I like my own chart best in the Koch system. (And
believe me, for most astrologers, this is the only honest
answer!)
Joyce Wehrman, whose system of Winning Transits is
offered through Astro (see Information Special IWINX),
was a strong advocate of Koch houses, and Koch house
cusps are an important part of her Winning system.

Equal
Astro’s third most frequently ordered house system is Equal
Houses. No doubt this is because a significant number of
people prefer to avoid the whole controversy of dealing
with interceptions and unequal houses. Here the ecliptic is
divided into twelve equal houses by lunes (think of lunes as
sort of like 12 sections of an orange) whose poles are those
of the ecliptic itself. The Ascendant is the cusp of the first
house, and each successive house cusp is then the same
degree of the next sign. The Midheaven rarely winds up on
the 10th house cusp and instead usually falls somewhere in
the 9th or 10th house. This system is said to have been used
in India around 3000 BC (and is still used there today), so it
“takes the prize” for antiquity, so far as we know.
Of the other house systems we offer, none are ordered
in any great volume, but each has its strong advocates, so
that is why we make them available. So…in no particular
order:


Meridian
Here the MC is the cusp of the 10th house and the East Point
or Equatorial Ascendant (whichever you prefer to call it) is
the cusp of the 1st house. (The East Point is defined in
Information Special IXBX, which covers the freebies you
can request on your basic charts). The equator is divided
into 12 almost equal arcs by lunes from the poles of the
celestial equator, and the intersections of the lunes with the
ecliptic are the house cusps. This system is fairly widely
used among Uranian astrologers.
system is entirely different, it produces cusps that are within
1° of the Placidus cusps up to about 56° north or south
latitude. Avid proponents of the system would say that this
is not enough, for primary directions to topocentric cusps
“work” within very few minutes of arc. Those interested in
exploring this system might like to order Dr. Margaret
Millard’s The Genetics of Astrology: A Study of the Topocentric
System, which demonstrates these extremely close
primary direction “hits” through fascinating case studies of
members of her family.


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