Cuspal by Sign and by House

by Marilyn Muir, LPMAFA

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There is so much discussion in the astrological community about cuspal conditions, by sign and by house. I am going to borrow from material I previously published for an explanation*.

“Astrologically, ‘cusp’ is a common word that is used for both signs and houses. A sign cusp is that point where the end of a sign gives way to the beginning of the next sign. A house cusp is the degree, sign and minute of the dividing line between houses at a specific earthly longitude and latitude. Let us take a moment to back up and understand some basics before we attempt to move forward.

“Signs: Think about the space outside our world where the zodiac seems to reside. Notice I said “seems to”. Earth’s path and the path of most of the other planets around the Sun is called the ecliptic or the path on which eclipses occur. This ecliptic passes through twelve of the sixty or so constellations, depending on which constellation reference systems are used. This specific collection of twelve signs is called the zodiac (circle of animals) that range on either side of the ecliptic, which again is the centerline of the zodiacal constellations. The constellations in general and the zodiac in particular are not located at a specific distance from Earth or anywhere else. The zodiac constellations are just somewhere out there outside the ecliptic and extend out into space for an indeterminate distance. The stars that make up each constellation are light years apart within each grouping so each constellation is huge in terms of the space it occupies.”

“Additionally, there are no fences in space to create a clear demarcation of space dedicated to a sign, they just run into one another at a somewhat obscure meeting point.” The constellations are of irregular length (zodiacal longitude), but corresponding signs are thought to have an average of 30 degrees each. Who made up these conflicting rules? I doubt if it could get much spacier than this, but I can tell you from personal experience that the twelve-sign zodiacal system does work.

“So, each of the zodiac signs is thirty degrees long and just runs into the sign on either end because there are no fences or physical transition points in space that I know of. We number the celestial longitude distance in the sign from zero to 29, with thirty degrees becoming zero of the next sign. But there is no physical division in space. Enter the word “cusp”. The transition between one sign and another is referred to as the cusp.  The explanation for sign cusp is not complicated. A sign cusp is the transition point between one sign and its neighbor. Technically the accepted transition occurs between 29 degrees and 59 minutes of any sign and 00 degrees and 00 minutes of the following and adjacent sign. This is true of either end of a sign, the beginning or the end. 00:00 is the beginning and 29:59 is the end of any sign.”  Occasionally you will see a reference to the 30th degree of a sign, but that is simply an indication that whatever is being listed has not quite moved into the latter sign.

“It is the planets that are read as being in a sign, which is a simple explanation for the appearance of a planet, which is closer to us as it passes in front of the zodiac constellations. The zodiac is located in outer space beyond our solar system. Therefore, the planet is seen with the sign as a backdrop. How do you know which planets are cuspal? Astrologers usually allow three degrees at the end of the sign and three degrees at the beginning of the next sign. That would equate to 26 degrees and 59 minutes to 29:59 for the end of a sign and 0 degrees 0 minutes to 3 degrees 0 minutes for the beginning of a sign. Astrologers would simply say plus or minus three degrees to the change of any sign.”

“How do astrologers read this? There is a blending of energies that occurs at a change of sign, a blurring where the signs are not as distinct. One influence is waning, one is emerging. Both are involved, but in a blended way. The strength of one diminishes as the influence of the other sign becomes stronger. This is a gradual process over six degrees of space. I have a friend who was born with the Sun at 29 Aries 55, almost into Taurus, plus she has four planets in Taurus. Day to day, you see a very strong Taurus influence, but do not ever forget she is an Aries. She is fully capable of acting as an Aries whenever she finds it necessary. Her Aries has not vanished it just is sublimated to some degree, buried under all that Taurus. Aries can still appear whenever it chooses. Astrologically she is an Aries with very strong Taurus overtones, or cuspal.

“Houses are 12 divisions of the physical Earth relative to the longitude and latitude of birth at a specific moment in a day. Again, there are no actual fences. Nowhere on this physical globe are there physical fences that act as dividers for the house systems. There are almost eight billion people alive on this globe, and we would need to employ twelve fences each. We would get nowhere, ever, if we had to encounter physical fences of that number and variety. So the cusp is a metaphor for a dividing line. My favorite description of a house is an arena of physical experience. For example, house one is your body, house two is your moveable possessions, house four is your family, your physical house, etc. Due to the curvature of the Earth and the interaction between the Earth and the zodiac various house systems, there are differing amounts of space allotted to each individual house. The house system maps our physical position on the Earth. A cusp is a handy dandy reference tool for knowing where the influence of one house ends and another begins, where one arena of physical experience gives way to another arena of physical experience.”

“Generally, five degrees is the orb or influence allowed for house cusps. If a house cusp is at ten degrees, you would then watch for a planet between five and fifteen degrees as having the potential of expressing in either of the two houses adjoining the cusp. It is important to know that transiting planets occupy any house for around two hours every day, more or less as you head away from the equator to your latitude line. As most astrologers know, high latitudes can produce multiple intercepted signs – but that is a subject for another day.”

“The average planet occupancy of a house is approximately two hours. As a planet moves out of a house in which it has spent a couple of hours, it carries with it a heavy influence of those house issues and may take a little time to grow out of that influence, or about five degrees. This is equal to about twenty minutes on a birth clock. As it enters the new house, it retains the influence of the previous house, and gradually that influence lessens until it disappears altogether and the new house influence becomes not only dominant but also exclusive.”

“I may lose a few of you at this point, but I don’t want to leave this out so bear with me. This single paragraph section is the only really technical part, I promise.

  • The signs travel counter-clockwise around the wheel.
  • The planets travel clockwise as the house cusp (signs) advance.
  • The cusps move counter-clockwise faster, variably than the planets move clockwise.
  • Each planet travels through every house every day, with an average of two hours per house.
  • The existing influence that is passing out of influence as time progresses (past to present) is the later (higher numbered house) of the two houses in question.
  • The incoming influence (now to future) is actually that of the lower numbered house.
  • The planet is actually occupying the houses sequentially but in reverse order.
  • Go over that several times and look at a wheel to fully understand what I just said. For a visual reference, move your fingers to simulate the planet and cusp motion.

An example might help. My Mars is in my 4th house directly on my 5th cusp. Because the cusps move faster than the planets, prior to that birth moment Mars was in the 5th and had just moved into the 4th by sign on the cusp movement. The 5th house has had about two hours of influence to and from that Mars, but that is now giving way to the developing 4th house influence. To do this cleanly takes about five degrees of cuspal motion, or about twenty minutes on the clock. Can you see this would not be a simple reading? It could be important to know that both houses are influencing that planet. Mars is in the 4th legitimately, but is residually influenced by issues from the 5th house. This cuspal condition could affect any reading of my or anyone’s wheel. As a participant in this experience, I can clearly see how both my houses are affected by this placement. “

Liberal quotations in this article were taken from my E-Zine online article*: “Astrology Cusps – More Than You Ever Wanted to Know About Cusps”.

The whole article is available at

Published in AFA Today’s Astrologer Jul 2012, vol 74 #7, republished with slight editing.

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This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.