Precession of the Equinoxes

Precession of the Equinoxes

Precession of the Equinoxes

The Precession of the equinoxes is a process whereby the position of the stars and constellations gradually move in relation the seasons. This means that the twelve astrology signs that once roughly aligned with the constellations of the same name, no longer do. The rate of precession is one degree every 72 years = 0.838 minutes per year, or more precisely, 50.2675 seconds per year.

The word Zodiac comes from the Greek zõdiakos (animals) kuklo (circle). It refers to the constellations of stars around the ecliptic. The ecliptic is the path that the Sun, Moon and planets take through the stars as viewed from Earth. Astronomers still refer to the zodiac as this path through the stars and constellations.

Astrologers refer to the zodiac as the 12 equal Sun signs of celestial longitude. Once upon a time, astronomy and astrology were one, and the shaman, druids, or priests simply divided up this ring of stars into varying numbers of constellations depending upon the culture. For example, in ancient Babylon the circle was divided up into 17 or 18 constellations of varying length. In ancient India, this ring of stars was divided up into 27 or 28 lunar mansions of varying length based on bright stars.

Astrology is the study of the effects that celestial objects like planets and stars have on us down here on Earth. It was always based on the spatial relationships between the planets and between the planets and the stars. That is why the original zodiacs were star based. Because some cultures evolved from a nomadic to a farming way of life, a new zodiac was developed based on seasons.

It was a calender really and was eventually divided up into 12 equal segments which is the zodiac we use today. It was developed around the 7th century BC and as an ecliptic coordinate system, it:

was a convenient celestial measuring device, unrelated to astrological activity…it was being used at that time for the recording of astronomical data, yet observation of the effects of the planets for astrological purposes continued to be related to the visible constellations. [ Heavenly Imprints, Deborah Houlding]

Measuring Device

The 12 equal segments in this calendrical measuring device were named after the twelve major constellations around the ecliptic, Aries, Taurus etc because the sort of roughly fitted in at the time. It was a very rough fit though, constellation Virgo is 46 degrees in length while constellation Cancer is only 4 degrees long across the ecliptic. Gradually the astrological meaning of the constellations was transferred to this new measuring device and the thing was given interpretive meaning.

The divisions are called sun signs, named after the constellations but now not at all related to them, purely symbolic. What we know as horoscopic astrology today is the result, and most astrology, Western and Vedic, traditional and modern, comes from this. All the rules such as elements, sign rulers, detriment etc are based on these zodiac signs, or Sun signs.

These abstract ideas were cemented in a book called Tetrabiblos by Claudius Ptolemy (Ptolemy) in the 2nd century AD. He adopted an astronomical calculation concerning the starting point of the zodiac which resulted in a fictitious moving (tropical) zodiac being popularised, which became the basis of the birth of modern Western astrology.

Now astrology shows little resemblance to it’s origins. The signs of the zodiac we use today do not relate to the constellations from which they derive their name and meaning. The idea of having 12 equal segments reflecting the influence of the stars is a nonsense. Even stars within a single constellation can have very different influences, and of course there are many more constellations to consider that are not on the ecliptic. To make things even more ridiculous, precession of the equinoxes in the last 2,000 years means the constellations are a whole sign away from the sun signs bearing their name.

Precession Astrology

Precession is the movement of the stars in relations to the ecliptic. They move forward through our tropical zodiac by about 5 minutes every 6 years, so in one lifetime, or 72 years a star will move one degree forward through the zodiac. This is because the Earth is tilted and moves around this axis every 26,000 years.

Vedic astrologers get around this problem by using the sidereal zodiac, it keeps moving with precession. It’s a patch up job which tries to resolve the problem by matching the Sun signs to the constellations of the same name. However this system is still based on the incorrect assumption that these 12 equal divisions reflect the influence of the irregularly shaped constellations. The rules of Vedic astrology are based on this. When the tropical zodiac was developed, zero degrees of Aries matched up with the first star in constellation Aries. Mesarthim, “the First Star in Aries, as at one time nearest the equinoctial point (392 BC)” [Star Names, Their Lore and Meaning, Richard Hinckley Allen, 1889, p.82.]. That star is now at 3 degrees Taurus.

Ptolemy and the Hellenistic astrologers that followed knew about precession but they chose to ignore it.

There was, perhaps, a more pertinent reason why the astrologers of the early Classical period chose to ignore this matter, one that suggests that by covering up this ‘inherent flaw’ of the zodiac, they were also obscuring a philosophical problem that had wider implications…It was tempting indeed to turn a blind eye, to let some other astrologer deal with it in some future generation when it really mattered. [Heavenly Imprints, Deborah Houlding]

It really matters now. Astronomers and skeptics can easily make astrology a laughing stock because of precession and they continually do so.

Johannes Kepler

I use the zodiac at it was originally intended, preferring to use the tropical zodiac to describe the position of the stars and planets. The degrees of the tropical zodiac are a universal way for astrologers to communicate where a planet or star is, that’s all. The interpretation comes from the relationship between the planets – the aspects, and from the influence of the fixed stars. What I’m doing is nothing new.

The great astrologer Johannes Kepler had a solution to this problem – he basically abandoned the zodiac and built his astrological system around the aspects between the planets. He thought that the zodiac itself was merely a human geometry exercise and primarily served to aid the memory of astrologers as they computed aspects in their heads. [The Zodiac: Sidereal Vs. Tropical, Bruce Scofield]

I also correct for precession to work out transits. Robert Hand, one of the most respected astrologers in the world says:

it is possible to treat the tropical zodiac as if it were moving. In other words, one should treat the natal positions of the planets as if they were fixed stars…My own experience has been that in timing an event the corrected positions are more accurate than the uncorrected ones. [Planets in Transit, Robert Hand, 2001, p.29-30.]

Nearly all astrologers continue to use the Sun signs for interpretation but it has to be understood that these interpretations are purely symbolic, not based on our relationship to the cosmos. It is similar in a way to the use of the cards by a Tarot reader, it aids the intuition to help in a reading.

Taking the meaning of the signs a step further by using rulerships and detriments, even saying someone is lacking in an element such as fire is fundamentally flawed. Astrology is based on the principle that the stars and planets have an effect on us down here, summed up by the words of Hermes Trismegistus, “As above, so below”. It is the planets moving across the backdrop of the stars which influence our lives, not the planets moving through imagined 30 degree divisions on a piece of paper.

A mistake two thousand years ago took root following the Menai massacre of 61 AD. The Druids, the most feared and revered astrologers of all time, left no writings. It’s all in the mind.

69 thoughts on “Precession of the Equinoxes

    • You’re in the majority there Lucy. Best way to test it out is to look at your Pluto transits. Write dates in diary for precessed and non precessed to personal planets. Can be inaccurate for transits to AC and MC if the time of birth is out by even a few minutes.

  1. This is a bit much to get the mind around for me. In the now, Uranus is in fact in Aries and because we use a tropical chart in Western analysis, have we have corrected for the inaccuracy of the historical divisions of constellations? I am a bit lost here. How do you approach an interpretation of a modern chart in one of the common systems of house division – say Placidus for example? Are we to not pay too much attention to the house?

    • I don’t know if the tropical chart has been corrected or changed at all since it was invented, except by the Siderealists. Uranus is in tropical Aries but I avoid all the confusion by saying it is on the fixed star Deneb Kaitos in constellation Cetus.

      I don’t use the houses myself but Marina like most astrologers does.I think she uses Koch.

  2. I noticed that the tropical and sidereal charts are the same in 221 AD.
    I actually did charts for the vernal equinox in Athens, Greece.
    Sun went into 0’00 Aries on March 21, 221 AD in both charts, and it was only 3 minutes apart. 6:36 AM for the tropical chart and 6:39 AM for the Sidereal Chart.

    I am thinking that I am just better off without using a zodiac chart.

    I thought about focusing just on aspects.
    I thought about using multidimensional system
    using not only Ecliptic Longitude but also Right Ascension and Declination. The Astronomers use Right Ascension and Declination to locate objects.

    As for fixed stars, well…I wonder about using paran method like Bernadette Brady. She doesn’t believe in projecting stars onto the ecliptic. She also pointed out that Ptolemy measures stars by the Pole of the Ecliptic and that now has been changed to measuring stars by Pole of the Equator by Ulugh Beg.

    There is also the issue of which day to use with the parans.

    She uses sunrise to sunrise which was the Egyptian,Babylonian day
    instead modern day of midnight to midnight.
    I think that it would makes sense to use midnight to midnight because we live in modern day. I feel that our brains are naturally attuned to this day cycle.

    • I think whatever system works for you, works. There are SO many astrological languages, we would go bonkers if we tried to test them all. But you are right in pointing out that as soon as we find a method that we think makes sense or is “scientific” we find something has been altered along the way. All theories about the universe are just theories. Facts change everyday as we learn more, as we grow more. The world and life are not static.
      The best way is to create your own benchmark and test it out empirically. You can present that research to the world and if it resonates then you know you it has some truth. The more people it resonates with the stronger the meme and then it becomes a school of though and a language.
      I have a lot of respect for Brady, but I just do not like parans at all. I like her updated interpretations for the fixed stars and I think they work for the ecliptic method too just like Jupiter is still basically Jupiter whether you use hellenistic or psychological astrology. (With variations I grant you, but the archetype remains the same).
      I think Diana Rosenbergs idea of using starsets is interesting, I have thought about this myself in using decans, there will be a set of stars in each decan, some further away by declination, so they have less of an influence. But I definitely see a bunch of traits from a few of the stars say in decan one of Aquarius that make early Aquarians different from late Aquarians. Then we get onto the zodiac signs which I believe do have some value. I will continue with this line of thought in answering Robbie below.

      • Hi Marina,
        I hope all is well with you and Jamie.

        I have been reading stuff in regards to Cyril Fagan and other Sidereal Astrologers, I feel like I can no longer use the Tropical Zodiac system. I am checking out the Cyril Fagan System with the use of the Sidereal Zodiac and Campanus House system.

        I noticed that the difference between my tropical and sidereal Solar Returns are 10 hours apart. That is a big difference. I am definitely scratching my head and wondering. I am going to pay attention and see how things turn out.

        I am iffy about the paran stuff, and I find myself falling back on the use of ecliptic projections.
        The Sidereal Astrologers do use fixed stars like that. They use Right Ascension with them too.

        I wish that there was a program that does the 13 constellation zodiac. One of my reservations about the Sidereal Zodiac is the fact that it is not the actually constellation zodiac. My Sun is in Virgo constellation and not in Libra constellation even though my Sun is in Libra in Sidereal Zodiac.

        I will probably ending up being like Johannes Kepler, just throw the signs and houses away and just work with aspects. I also like Cosmobiology with its strong emphasis on midpoints.

  3. Thanks so much for this!!! You are saying what I have been saying for a long time! I agree entirely that the constellations of the zodiac are merely a useful reference system, that the rulership, fall, detriment and all that has no basis BUT I dont agree about the elements… I think they along with the cardinal fixed mutable things are valid, due to sub-divisions of seasonal characteristics.
    In the way that we can (presumably) agree that what we refer to as signs do have discernable characterisitcs… and can spot the traits of what is described as the signs, but is actually coming from the earth#s seasons….. I can recognise an earthy, or non-earhty person, a fiery or not fiery one, etc…. but agree quite joyously that these traits are not due to the influence of the constellations.
    Thanks again!

    • I think the point of the post is that Jamie thinks that neither the tropical zodiac nor sidereal zodiac are valid zodiacs for determining signs and traits. He doesn’t that a star-based zodiac nor a season-based zodiac are valid in Astrology.

      “In the way that we can (presumably) agree that what we refer to as signs do have discernable characterisitcs… and can spot the traits of what is described as the signs, but is actually coming from the earth#s seasons”

      What you are referring to is the tropical zodiac, and that is something that Jamie doesn’t agree with.

      He doesn’t agree with the sidereal zodiac which is based on planets against the backdrop of stars

      the tropical zodiac is invalid because of the precession of the equinoxes

      Ptolemy based his Tropical Zodiac Astrology on the Northern Hemisphere seasons without knowing the Southern Hemisphere. If he did know, he chose to ignore it.

      Jamie is in Australia,and so he lives in Southern Hemisphere. He understands the issue with the seasons.

      You can’t just apply Euro-centric model to everything else on Earth.

    • I think the traits are a mix of the seasons and the constellations. I also agree with you about the elements. I definitely get the sense of a fiery or an earthy person. But as I am married to someone of the southern hemisphere it does somewhat turn everything on its head when it comes to taking the season thing too literally.
      I see the astrological wheel more as lunar phases.
      The New Moon
      The Crescent Moon
      The First-Quarter Moon
      The Gibbous Moon
      The Full Moon
      The Disseminating Moon
      The Third-Quarter Moon
      The Balsamic Moon
      It’s the same story. It’s all about cycles and the growth and death of a plant. Tropical astrology was devised in the northern hemisphere. But I do see the polarities in the zodiac as being the same. I see pisces in Virgos and Leos in Aquarians. The mode is the same. Also Causcasian Australians are hardly indigenous I think their cells still respond and resonate with a northern hemisphere system, although I think there could be a case for considering whether the opposing sign may fit them more while they are in the southern hemisphere! Specially stelliums. I feel more sunny Leo in Oz! I can see the Pisces in Virgo Jamie too. I’ll see if he is more Virgo in London when he comes. lol!

      Back to the Moon/seasons analogy. Its 8 phases rather than 12 (Months). But division by 8 was also some of the early house systems. Also the pagan seasons are divided 8fold, in tune with the lunar cycle.

  4. I just found your web site, and I’m getting more exited as I read!
    It was not to long ago I “found out” about sideral astrology, and realized tropical astro is, well, it is just a mockup! So I was kind of discouraged when you refer to the tropicla signs – why don’t you refer to the sideral signs, as they more are in line with the starry sky – and WAS going to ask you about your opinion on sideral astro. And now I find you have discarded even that, and gone back to the true roots – the stars! 😀

    But then I wonder… Are you saying that even sideral astro is off? Are you saying the stars have wondered even more than the 1°/72 year?
    And to be practical: I use this astro program, and have set the 0-point as 15° Taurus, since I found this info somewhere and it resonated with me. But then I use Geocentric calculation. Should this better be heliocentric? Or what? And so where/how do you get your data??

    I want to learn and understand this much more, but I’m still just scraping the top layer…
    Funny thing is I’v always been interested in astrology, but have NEVER managed to learn about the houses, but have only dealt with planets and aspects. I start to think I had some unconscious clue here… 😀
    Would really appreciate some clues, tips, and links to others with your approach, to learn more! 🙂
    Thanks! And… Wow! 🙂

  5. Hi Jamie – I found this interesting page today regarding precession and thought of you because I always liked your explanation. What always amazes me is how different the planets are in the Vedic astrology charts – and yet people always say that both systems work! :o) FYI:

    “… to bring in continuity, we need the Ayanamsha Correction.
    The western astrology follows tropical zodiac – which the Vedic system follows a sidereal one. Throughout the history of astrology in India and other countries of Indian subcontinent, the capabilities of the sages in terms of observation made them realize that there is a slip, or a wobble in the earth’s axis. There was a need of introduction of a factor in calculations called Ayanamsha Correction. This mathematical correction, which amounts to the slip in zodiac over a period of time converts the system from tropical to sidereal. After application of this factor, things fall in place. Sun, according to the sidereal system can really be observed within the zodiac sign that the calculations point to.”

  6. “In ancient time, down to as late as the 5th century A.D., all revolutions were computed in terms of the fixed or sidereal zodiac, which is not affected by precession; whereas in modern times these returns are computed with reference to the tropical zodiac invented in error by Hipparchus about B.C. 139 and which the author [Claudius Ptolemy] of the Tetrabiblos (2nd century A.D.) strove to popularize.”!tropical-vsidereal-solunars-/c1nbt

  7. Hi Jamie,

    That’s very interesting. It makes a lot of sense. It’s practical and scientific. I do believe in marrying the occult with science; otherwise I will always have a level of doubt about something. I can have much interest in a certain area of ‘the occult,’ but I will always question it. Things have to be realistic. I don’t like to be fooled. You told me some time ago that my closest star is Izar (28 degrees in Libra). Does this mean that I’m a sun sign Libra? My birthday is the 24th October, 1988, Southampton, England at approximately 6:06pm.

    Does this mean that many people are different sun signs to what they thought they were?

    And yes, it doesn’t make sense that the 12 equal divisions of the zodiac are supposed to fit the irregularly shaped and sized constellations. I wouldn’t want to be ignorant and ignore the importance of the stars. It’s just a shame that more isn’t written about my closest star Izar.

    Very curious. A lot to ponder…


    P.S: I’m very much interested in astronomy too and in the past, when I’ve looked up at the constellations and observed the differences in the size and shape of the constellations, it has made me wonder, when it comes to the precision of the zodiac.

    • Katie, yes your Sun Sign is Libra, decan 3. You actually have no major fixed stars within orb of your Sun.

      People are always the same Sun Signs but they will have usually have a different constellation. For example you are Libra Sign but Virgo Constellation. Sounds like you would love researching archeoastronomy. You can study it in the UK now, it at some University and run by Nick Campion.
      You will have other stars in your chart for example Moon conjunct Alpherg, Venus conjunct Alkes and Pluto on the astrologers star Acrux.

  8. Hi Jamie, where I’m born on the cusp, does that mean I’m Sun sign Scorpio too? And will I also have Scorpio traits? On these websites where you put your date of birth in, it gives me 1.33 degrees Sun in Scorpio. I don’t mind being a Libra, I’ve just always been used to being Sun sign scorpio (on the cusp). And also, does that mean that I would have Virgo traits too? I can be overly critical of myself, I have worried a lot over the years and I’m a perfectionist like Virgo. My black moon Lilith is in Virgo and also Venus.

    I’ll look into Archeoastronomy. I can’t go on any courses at the moment, as I’m busy trying to run my design business (I’ve only set it up in the last year), but I look into courses in the future. I can always read books for now in my spare time. I will also look up these other stars that you’ve listed.

    • Definitely Sun sign Scorpio but the point is that there are no Scorpio or Libra traits. Signs have no energy so cannot influence you. Look up at night and find 30 degrees Libra. Stars emit the energy, more so even than planets. Planets act like conduits for the stellar energy. degree

  9. So where the Sun is concerned, the energy emitted to me at birth is from Libra 28.06 degrees in Izar. And the Sun aspecting planets in my chart, which are Sun opposite Moon, Sun Sextile Saturn and Sun Sextile Uranus.

    People say; “I’m a Sagittarius… so I’m like this or that,” for example. So that’s not really true? Or someone’s a Sun sign Gemini, so they have a ‘dual personality.’ Sorry for all the questions, but if I didn’t appreciate what you had to say, I wouldn’t ask. My sisters a Sun sign Leo, but has never felt that her personality is like a Leo and I completely agree with her! I don’t feel that I’m that much like a Scorpio either, but feel that my personality is more Libra.

    Thanks for all your input, it’s helping me figure things out! I want to get it right in my mind, if I’ve learn it the wrong way all these years. But I am an amateur at astrology, I don’t know that much about it.

  10. This problem has concerned me for a long time. Ever since college days when a friend offered to teach me how to do a chart in the 70’s. A few points if I may, not inorder of importance: I don’t understand the seasonal controversy. If the sun is somewhere in the heavens on the day of your birth, is it not in the same spot relative to the earth no matter where you are? A point drawn out from the center of our planet to the sun at the exact time of your birth is really all that is needed to place the sun somewhere against the back drop of the stars, in some 60 degrees of some sign. The house relationships would account for hemispheric differences just fine since they are relative to the earth not the sky.

    Second: I don’t see why we have not corrected for procession by now with all the other changes in our understanding of astronomy since Ptolemy. Can’t we just do the math on this for our sign placements? I recently did the calculation for the fixed stars in my chart. Thank you Jamie for coming up with an amaizing new tool! Accounting for procession of the planets was a simple matter. Why can’t we have a formula like that to process the signs in our charts for our birth date and time? It’s really tiring to listen to the old arguments for sidereal, tropical, Asian and other formulas.

    Lastly I have a technical question about the ephemeris we use today. Is it accurate? Does it give us the proper placement of the planets? Because if it is off too, I think we really should throw out the baby with the bath water and start all over again with accurate tools.

    On The question of the division of the sky into 12 equal parts and keeping the 12 signs I come down in favor. 12 is a spiritual number and a good way to balance the heavens. While it’s true that actual constellations take up differing amounts of space in the sky, that is just part of their charm and will find expression in reading them. Now that we have a better understanding of fixed stars and we can add that layer over top, there’s no need to rescale the heavens.

    • Well said. The software I use is Solar Fire which has an option to account for precession when doing transit and return charts.

      I also have some sympathy for 12 divisions. Mainly since I heard that the core of Earth, a single Iron crystal the size of the Moon, is a dodecahedron.

    • Add 0°18’to your planets to get to the yr 2000 fixed star positions.

      When working out your precession corrected transits, add 0°31’to your natal planets.

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