Gauquelin’s Mars Effect REVISITED

“When will the Astrological community admit there was an error?” Michel Gauquelin

There has been much comment and speculation about the results of Michel Gauquelin’s Mars Effect research because it indicated that the greatest percentage of accomplished sports persons have their Mars located in their 12th house – with a secondary peak in the 9th house.  Gauquelin used a house structure, which he called sectors, very similar to the Placidus house structure for his research and the 12 axial lines represent the cusps of the 12 houses/sectors in Figure 1.

Figure 1 – the 12th house peak effect for Mars in the horoscope of eminent sports persons appears about 10 degrees before the ascendant in the 12th house, with the secondary 9th house peak about the same 10 degrees but before the MC, mid heaven or 10th house cusp

Figure 1 – the 12th house peak effect for Mars in the horoscope of eminent sports persons appears about 10 degrees before the ascendant in the 12th house, with the secondary 9th house peak about the same 10 degrees but before the MC, mid heaven or 10th house cusp

There possibly are some problems associated with this research, principally of an arcane statistical nature, but the main charge leveled against Guaquelin is that he selected only those athletes that conformed to his desired end result.[1]  This just does not make sense as no one would expect that the peak effect for athletes would be found by having Mars primarily located in the 12th house, followed by the 9th.  This totally disagrees with traditional astrological lore.  If the results conformed to traditional astrology, the Mars effect should have first appeared in the 1st house, followed by the 10th house.  This applies to both western and Vedic astrology.

Consequently, Gauquelin’s result has perplexed astrologers.  This anomalous result suggests that, provided Gauquelin’s integrity in preparing the data for his statistical research was in place, he has produced an anomalous result that undermines a fundamental aspect of contemporary western astrology that cannot be brushed aside – though astrologers have collectively behaved like ostriches with their heads stuck in hole in the ground over this issue.  However, Gauquelin’s perverse research result may not be as anomalous as initially perceived.

Gauquelin’s research was carried out at a time when astrological houses in western astrology were relatively uniform – from my memories of the 1970s and 80s, nearly everyone used the Placidus house system, and any other astrologer using a different system usually used a very similar alternate ascendant based house system (Note: ascendant based house systems usually have the 1st house commence with the ascendant degree).  The subject of house inconsistencies was either never or rarely mentioned.  If Gauquelin had produced his results using a variety of different house systems, he may have arrived at a totally different result but houses were not an item of controversy in his time.

Times have changed, and many astrologers have subsequently noted the glaring inconsistencies of the plethora of western house systems.  As expected in the world of astrologers, there are many different schools of thought on how to approach houses.  One school is that each house system has a unique angle or perspective and that each astrologer uses the house system that works personally for them.  Many astrologers do not even reflect upon houses, and just use the house system they were taught based on the fact that astrology works for them, so their house system must be OK!  Some astrologers have switched house systems one or more times based on a variety of arguments or due to a reputable astrologer extolling the virtues of a different house system.  The commonality is that there is no consensus to houses.

I am going to provide an alternate explanation of the Gauquelin’s Mars effect that does not show a primary peak in the 12th and secondary peak in the 9th, but rather the primary peak is in the 1st house and the secondary peak is in the 10th house where such peaks should be expected.  This alternate result is found by using the whole sign house system – the original house system of the Hellenistic astrologers who invented modern horoscopic astrology used in both the West and India though the Indians use a different zodiac.  The whole sign house system is radically different to ascendant based house systems such as Placidus.

Note: The remainder of this blog is ‘dated’ inasmuch, later research has pointed to a totally different solution to what I have expressed below, but I am leaving the following as a work in progress.  A better solution is available in a later blog “Gauquelins’ Mars Effect Graph SOLVED

The consensus amongst researchers in the field is that the original house system developed by the Hellenistic astrologers was the whole sign house system.  Western astrologers relatively quickly turned away from the whole sign house system and seemed to embrace ascendant based house systems probably due to being hypnotized by the power of the ascendant and MC (midheaven).  The first stage appeared quickly in the 1st century AD with the introduction of the equal house system where the ascendant commences the 1st house with all houses exactly 30 degrees each.  Consequently, the MC (midheaven) is not usually on the 10th house cusp.

By the 3rd century, another development called the Porphyry Houses appeared that basically made the 10th house cusp equal to the MC (midheaven) resulting in 6 smaller houses of equal size and 6 larger houses of equal size.  It is basically a simplified version of most modern ascendant based house systems such as Placidus.[2] However, these same house ‘evolutions’ never occurred in India, and the great majority of Indian astrologers have kept true to the original whole sign house system of the Hellenistic astrologers but using the sidereal zodiac in place of the western tropical zodiac.  Some secondary Vedic house systems do base themselves upon the ascendant degree one way or another.

In the whole sign house system, no matter what the ascendant degree, the 1st house is always zero to 30 degrees of the sign the ascendant degree is located, with all the remaining houses following the same structure.  Therefore if someone has their ascendant at 10 degrees Cancer, the 1st house is zero to 30 degrees Cancer, the 2nd house zero to 30 degrees Leo and so on.  This can appear confusing to astrologers used to an ascendant based house system because many astrologers think that the power of the ascendant degree moves from the ascendant degree to the zero degrees of the 1st whole sign house.  This is not the case.

In the whole sign house system, the most powerful point in the horoscope remains the ascendant degree, followed by the midheaven and so on.  The biggest change is that the ascendant degree, though the most powerful point in the horoscope, just does not start the 1st house.  There is unconsciously acknowledgement by many astrologers using an ascendant based house system that, for example, the influence of the 1st house commences before the ascendant degree.  Some use a 5 degree ‘orb’, one system uses a 15 degree orb and at least one astrologer acknowledges that regardless of the ascendant degree, any planet located in the rising sign is considered a prime factor in the horoscope (essentially treated as being in the 1st house) even if the planet is technically located in the 12th (ascendant based) house.[3]  There is no consistency or uniformity in these fringe approaches to ascendant based houses. However, the majority of astrologers using an ascendant based house system use the actual cusps as the delineating borders between houses.

The confusion about houses in western astrology, and the myriad claims made about house cusps with no consensus, seriously indicates that “there is something rotten in the state of Denmark” to quote Shakespeare.  This suggests that the solution to this problem has not yet been found, or if found, not acknowledged.

I remember when I first encountered Gauquelin’s Mars effect chart that I thought he was picking up the sidereal zodiac instead of the Western tropical zodiac, but in essence, the research is relatively free of zodiac issues as he just used the ascendant point as the fiducial point – and this does not vary in the two systems.  Therefore, this research is relatively independent of zodiac issues (but it may still have intruded into his research without being recognized as such).

Let’s look at the Guaquelin Mars effect chart from the whole sign house perspective.  The most critical requirement is understanding what limited information we have available from the Mars effect graph in Figure 1.  The ascendant line represents the ascendant for all athletes regardless of what sign the ascendant is located or what degree of the rising sign.  We don’t know the rising signs for these athletes, just the ascendant degree representing anything from zero to 30 degrees in any sign.  This line specifically represents the 1st house cusp in the Placidus system (and most ascendant based house systems), and all other axial lines represents the other 11 cusps of the Placidus system.

An overlooked piece of information that can be extracted from Gauquelin’s Mars effect graph is that while it is a mystery from the ascendant based house structure perspective, it is only slightly off-key.  The fact that the main peaks appear not too far from the ascendant and midheaven indicates that the main focus remains near the ascendant, and near the 10th house for the secondary peak.  So while this is unexplainable from an ascendant based house system, it suggests that the correct understanding is just a tweak away from the normal ascendant based house structure.

But what does the 1st house cusp in Figure 1 represent if we wish to view the graph from the whole sign house system?  For all the athletes, they could have had their ascendant located from zero to 30 degrees in any of the 12 signs. Therefore, the 1st house Placidus cusp represents a range of points from zero to 30 degrees (and the sign is irrelevant).  If the number of athletes selected for the study was statistically significant, then it can be assumed that the random distribution of ascendant degrees was relatively uniform.  Therefore there should be a relatively equal number of athletes represented at each of the 30 degrees available.

If the random distribution was relatively equally spread, the average rising degree should be 15 degrees (midpoint of zero to 30 degrees).  The 1st house cusp of the Mars effect graph in Figure 1 therefore represent the average location of the ascendant at 15 degrees (of any sign) and no longer marks the beginning of the 1st house.  This point marks the average middle of the 1st house and all other Placidus house cusps in the graph represent the average midpoints of those houses – see Figure 2.

Figure 2 – the Placidus-style house cusps (labelled P1, P2… P12) are no longer representing the beginning of each house but average the center of each whole sign house. The 12 red radial lines (labelled 1,2,3…12) represent the average cusp of each whole sign house.

Figure 2 – the Placidus-style house cusps (labelled P1, P2… P12) are no longer representing the beginning of each house but average the center of each whole sign house. The 12 red radial lines (labelled 1,2,3…12) represent the average cusp of each whole sign house.

The Mars effect peak at about 20 degrees in the 12th Placidus house in the graph is now also displayed as about 5 degrees past the average beginning of the 1st whole sign house.  The secondary peak no longer appears in the 9th Placidus house but is now located past the beginning of the average cusp of the 10th house cusp.  This agrees with traditional astrological lore which elevates the 1st house followed by the 10th house.  Ideally, the statistical data needs to be completely re-analysed based on the whole sign houses of the athletes to confirm this perspective.

Though the above simple insight and analysis provides prima facie evidence of a far better result for the Mars effect by applying the whole sign house system in place of the whole range of ascendant based systems, there is more information that can be extracted from Gauquelin’s Mars effect graph.

There is something very interesting and unusual in Figure 2 where the main 12th house Mars effect commences its rise slightly more than 15 degrees before the beginning of the average 1st whole sign houses (P12), and then symmetrically retreats about 5 degrees past the average 1st whole sign house cusp (P1).  In total, there is a 30 degrees ‘above average’ result which is basically replicated in the 9th house.

This almost 30 degree total for greater than expected athletes suggests that the one sign bandwidth for greater than expected indicates that the 30 degrees house/sign structure is important factor in the results.  Secondly, it appears that Mars when peaking above the ascendant is also most likely in the same sign as the ascendant and therefore located in the 1st whole sign house.  To explain why this inference is taken requires a closer look of the imposition of the whole sign house structure upon Gauquelin’s (Placidus) sectors.

Referring back to Figure 2, a sports person at P1 could have their ascendant at zero degrees, zero minute and 1 second of their rising sign or as late as 29 degrees, 59 minutes and 59 seconds.  This means that Mars can be in the ascendant sign as early as 30 degrees before this point (P12) or 30 degrees following the ascendant.  Mars can be in the same sign as the ascendant (P1) in a band 30 degrees either side of the point for a total of 60 degrees.

At any point in this 60 degree band centered on the ascendant (P1), Mars could be in the sign of the ascendant, or if past P1 in the sign of the 2nd house or if before P1, the sign of the 12th house.  We never know which sign Mars is located in any part of this graph, but we know Mars must be located in one of two signs at any point in the zodiac graph.  Furthermore, if the distribution of sports persons is relatively equal for each of the 30 degrees, we can know the probability at any point of the likelihood of which house/sign is most likely.

For example in Figure 2, any sports person with their Mars situated between (1) and (P1) is likely to have their Mars in the sign of the ascendant (P1). Also, any sports person with their Mars situated between (P12) and (1) is more likely to have their Mars in the sign of the 12th house. If the sports persons are relatively equally distributed in their ascendant degrees, we can know even more accurately the relative probabilities of Mars being either in the sign of the ascendant or sign of the preceding or following houses as these will be straight line functions.

The number of sportspersons with their Mars in the same sign as the ascendant starts off at its lowest point at (P12) and steadily increases to its maximum at (P1) while the reverse will be the case for sportspersons with Mars remaining in the sign of the 12th house.  Both probabilities are straight line functions with one increasing as the other is decreasing.

The increase in the likelihood of Mars’ location between (P12) until the peak effect of Mars at 10 degrees before (P1) suggests that this line is increasing with the increased probability that Mars is located in the same sign as the ascendant.  This strongly implies that the increase in incidences of Mars in the first 20 degrees of the 12th Placidus house is a result of Mars also being in the sign of the ascendant.   In an ascendant based house system, this increased activity is occurring in the 12th house, but in switching to the whole sign house system, this increased activity can be associated with the increased likelihood that Mars from (P12) onwards is in the 1st whole sign house.

What is so critical about 10 degrees that a fulcrum point is experienced?  The easy answer is the conjecture that 10 degrees before the angles is the critical astrological point for the maximum effect of a planet similar to heliacal risings (around 15 degrees) or Dorphory (the planet that rises before the Sun).  Gauquelin may just have uncovered a hitherto unknown definitive point in astrology?

The difficult alternative is that this fulcrum point may be related to the house and/or sign?  Considering that the two endpoints of the Mars 12th house effect appears to be directly related to house and/or sign suggests this 10 degree fulcrum point may also be related to house and/or sign.

Gauqulin’s graph was produced independent of zodiacs, as he was just looking for the position of Mars in relation to the angles and derived intermediary house cusps. If we look at his graph from the perspective of the sidereal zodiac, it shows that as the ascendant moves from 30 degrees sidereal down to 10 degrees sidereal in the sidereal ascendant sign, the Mars effect progressively increases until its peak around 10 degrees sidereal.  This is relatively close to the point where the tropical sign changes sign because of the difference (ayanamsa) of 24 degrees between the two zodiacs – the tropical zodiac is currently 24 degrees ahead of the sidereal zodiac.

Taking into account that this 24 degree reduces by one degree for every 72 years we go backwards in history for the birth times of the selected sportspersons, it is feasible that this 10 degree point is associated with the change in the tropical sign?  The difference between the two zodiacs was 20 degrees around 1800.

As an example, someone with 6 degrees sidereal Pisces ascendant is on the cusp of the beginning of tropical Aries (6 degrees Pisces +  24 degrees = 30 degrees Pisces or zero degrees Aries). Some of the difference between the observed 10 degrees peak and expected change at 6 degrees (6 + 24 = 30) can be explain partly by sports persons born in an earlier century?

Perhaps Gauquelin not only use the wrong houses, but also the wrong zodiac?  What if the Mars effect graph is primarily orientated towards the sidereal zodiac showing an effect of the tropical zodiac as a secondary input?  Something to ponder and research as this is pure conjecture?

Finally, it is worth noting that the lowest position for Mars in Figure 2 occurs towards the end of the 7th Placidus house (just before (P8)) but in the whole sign house system this occurs almost in the middle of the 8th whole sign house.  Again, Mars is better placed as a minimum in the 8th house which throws no Ptolemaic aspect onto the 1st house and is arguably one of the worst houses in a horoscope.  It is appropriate that fewer eminent sports persons have their Mars in their 8th house.

In conclusion, there is no absolute proof in this analysis that Gauquelin’s Mars effect proves whole sign house system.  However, it does provide strong circumstantial evidence that if the same data was re-analyzed, but reorientated towards using whole sign houses, there is an extremely strong possibility it will confirm that whole sign house system principally because the prime position of Mars above the ascendant is also in the same sign as the ascendant.  On a simple level, the “12th house peak” occurs past the beginning of the average 1st house whole sign cusp (and 20 degrees past the point where Mars could be in the same sign as the ascendant degree and therefore in the same whole sign house). This is almost impossible to not be a true reflection of the relevance of the whole sign house and the stake in the heart of ascendant based house systems.


While I have to revert to conjecture and assumptions in analysing Gauquelin’s Mars effect graph via the whole sign house system, there is something that does not depend upon conjecture.  The major point overlooked by most astrologers in interpreting the Mars effect graph is that Gauquelin fired a broadside at ascendant based house systems.  If his statistics have any integrity and there was no fudging, the Mars effect graph basically says that ascendant based house systems of all types and used by the great majority of western astrologers are nonsense.

Instead of taking this at face value, astrologers did what most people do in similar situations, “fight, flight or freeze” when faced with stress.  Astrologers have either ignored the work, discounted it like skeptics or allegorically rearrange the deck chairs on the Titanic even though Gauquelin was the iceberg that sank it.  In the absence of any effective counter argument, ascendant based house systems do not have a solid leg anymore to stand upon.

This does not mean that an astrologer using Placidus, or any other ascendant based house systems, will not get positive results, because there is on average a 50% overlap between ascendant based and whole sign house systems.  Furthermore, many aspects of interpreting a horoscope are independent or relatively independent of houses.

I am not the only astrologer questioning the integrity of western houses.  For example, Bruce Scofield states:

I was exposed to the wonders of “house cusp mental masturbation,” an activity that has fascinated the best minds in astronomy and astrology for ages. Although I could, more or less, follow the arguments for each of nearly a dozen systems, I found it hard to believe that all of these methods could work.

“…. consider that most people use Placidus for the same reason I used to — everyone else does….. So astrologers have been using a system that they can’t even understand”

“…. most house systems were just plain complicated”

However, the crux of the house problem that has confounded astrologers over the last 2,000 years is summed up by Bruce Scofield as:

“In my view, the first astrology is the four directions and this survives in modern astrology as the angles. They must then be the framework on which the houses hang.”[4]

In this statement, Bruce Scofield underscores the main problem in astrology, and especially with houses – the use of unproven astrological concepts that are incorrectly treated as axioms.  In other words, according to Scofield (and many others) he is basing the prime underlying premise of house structure directly onto the angles (ascendant, midheaven, descendant and IC) without looking for any proof or verification that this is a correct hypothesis.  The most important of the four directions does provide the framework for the whole sign house system, so this assessment is not totally incorrect.  It is probably due to this same reasoning that the four angles are of primary concern re the houses that the early astrologers turned away from the whole sign house system and commenced employing complicated houses with the ascendant degree the actual fiducial point rather than the beginning of the sign the ascendant was located.

“….. modern house systems seem to have been derived from a mistaken understanding of certain passages in Ptolemy. This creates vast problems for modern astrology (except for that practiced by the Hindus, which is virtually alone among modern forms of astrology in its use of whole-sign houses), but indicates more clearly than ever that the presumed contradiction between Gauquelin’s findings and houses is based on erroneous assumptions.”[5]

Astrologers, like all people in general, do not in general like change or the new.  Faced with evidence, research has shown that the great majority of people will hold on to an unproven approach and reject evidence that undermines their approach. The excuses provided to support their unproven perspective are generally theatrical in the extreme.  The first doctor that advocated cleanliness to prevent disease was forcibly incarcerated to a mental asylum!


12 Reasons Why Whole Sign Houses is The Best System of House Division by Chris Brennan,

“Whole signs – The Oldest House System” by Robert Hand

“History of the Houses” by Robert Powell

Gauquelin’s findings are due to biased sampling

The Gauquelin Research

Is Trump the Perfect Guinea Pig for Astrologers?


[1] Misunderstandings, Misrepresentations Frequently Asked Questions & Frequently Voiced Objections About the Gauquelin Planetary Effects


[3] Gwyn Turner, “The Complete Home Astrologer”, Thomas Nelson Australia Ltd, Melbourne, Australia, 1977, pp 24-25 (ISBN 0 17 005192 7)

[4] Bruce Scofield, “Why I Use Porphyry Houses”, – This article appeared in the Fall/Winter 1992/1993 issue of The Ascendant,  The journal of the Astrological Society of Connecticut


One response

  1. Reblogged this on Lost Dudeist Astrology.


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