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Rahu-Ketu: Directory of Jyotisha Descriptions

"Mean" versus "True"

positions of Rahu - Ketu

Q: What software do you use? Because some put Rahu in my 2nd house, which changes the whole interpretation as you have put Rahu in 3rd.

A: At the moment I use Shri Jyoti Star. But the issue is not the software. The difference is in the astronomy. The difference between claiming that your Rahu inhabits Simha 0: 2:44 claiming that your Rahu inhabits 29++ Karkata is the difference between Mean Nodes and True Nodes.

The important choice with setting the rashi of the nodes is whether the Jyotishi prefers to use the astronomical Mean nodes (more accurate) or the misleadingly named true nodes.

I use Mean Nodes. Rahu-Ketu which have no mass = an astronomical range of points, not a single point. The range exists in a small continuum that is sometimes called a wobble due to the curved pattern of the range. It is also said (by astronomers) that Earth's Moon wobbles when Moon traverses either Rahu-place or Ketu-place.

In the end, it makes much more sense to use a Mean point to establish mass-less Rahu's influence rather than an arbitrary True Point. True points only make sense for objects with mass.

Unfortunately, beginners who don't understand the astronomy often select True nodes because it sounds more accurate.

However, I could be proven wrong if any of your previous Rahu periods caused the phenomena of bhava-2: perhaps a death in your immediate family, usually the death of a parent or a child. If Rahu really was in bhava-2, then Rahu would be an empowered maraka there because Rahu's ruler would be nichha-Shani-Meza-5 who owns 2 casts drishti upon 2 and occupies 12th-from-Chandra .

If there was a death of a beloved parent or cherished child during Rahu-Rahu or Guru-Rahu, I would certainly revise my calculations - probably by adjusting the birth time as well. Otherwise, we can work with the Mean positions as those are generally more accurate.


I am an advocate of True Nodes, as I prefer the true compared to the mean in everything, also symbolically.

Secondly, mean nodes not onlyfail toreflect the actual positions of the nodes, but they now always seem to go retrograde.

This shows how Vedic astrology has degenerated over time: one can not obtain information anymore if the nodes go direct and stationary in reality.



The choice between true-logical nodes versus mean-observed nodes is debated among astrologers of all traditions. Generally among astronomically literate astrologers there is a preference for using statistical-mean nodes. Poetic astrologers who lack astronomical literacy may express a preference for “true” nodes because they are unfamiliar with the geometrical-versus-statistical calculation options and they presume that true equals authentic. Unfortunately, true in this context is a synonym for logical, not a synonym for correct or for authentic.

The difference between mean and true is astronomical not astrological. It is not a discussion about symbolism, but rather about measurement.

Because upagraha such as Rahu-Ketu have no mass (and thus to materialistic science they do not exist except as calculated points) Rahu-Ketu do not follow predictable material trajectories in the same way as mass-bearing graha. In fact, there is no reliable way to "reflect the actual position of the nodes" at any specific moment.

Astronomically speaking, Rahu-Ketu are the product of interactions within the intersecting projected atmospheric fields of Surya, Chandra, and Terra. Rahu-Ketu's location is affected by solar flares, by movements of mass within Earth's interior, and by the frequent shifting of the metallic core of the Moon, inter alia.

Graha are living beings! They have moods and they sometimes behave oddly for their own internal reasons.

Here are the key distinctions in calculation method:

  • True nodes are logical objects calculated geometrically.

  • Mean nodes are measured objects calculated statistically.

True nodes are calculated geometrically by assuming that the relevant points of the terrestrial barycenter, the plane of the ecliptic, lunar orbit, and solar orbit are all perfectly regular.

But astronomers know that there are a number of push-pull variations in the relationships between Surya, Chandra, and Terra which belie the expectation of harmonious, predictable regularity in this logically aesthetic model.

In reality, Rahu-Ketu wander and twitch in response to sporadic changes in the force-fields of Surya, Chandra, and Terra. Rahu-Ketu location is never specifically pinpointed. Rather it is closely estimated based upon the predictable range of the wobble effect that Rahu-Ketu impose upon the movements of Chandra.

Astronomical data shows that there is always some variation in the trajectory of Rahu-Ketu, due to the behavioral fluctuations of the other parties. Despite the obvious appeal of an orderly logical triangulation, historical data demonstrate that Rahu-Ketu cannot reliably be presupposed to be exactly where they would be geometrically expected to be.

Because geometrically fixed true nodes cannot accommodate the documented range of movement caused by irregular interactions between Surya, Chandra, and Terra, true nodes (as pretty as they are) cannot represent an accurate identification of the position of Rahu-Ketu.

Mean Nodes * calculated by statistical mean * Preferred

An arithmetic mean is a calculated midpoint position within a statistical range. Using an arithmetic mean to estimate the position of wandering-twitching hypersensitive-responsive massless Rahu-Ketu is not a perfect solution, but the Mean-Midpoint method offers a more data-accurate option than the abstract logical-true method. Predictions based on calculations involving other upagraha that are used in Jyotishavidya, such as gulika and mandi, also benefit from the arithmetic-mean method.

Although there continues to be discussion and (in some circles) an ongoing search for better calculation methods to identify upagraha positions, most modern, astronomically competent astrologers choose to prefer statistical-mean nodes.

Q: Why did you use mean nodes to calculate my charts, rather than true nodes? I don't like the sound of the word mean. Do you think I am a mean person? I would have preferred to use true nodes because I am always in search of truth. Why do astrologer say mean nodes or true nodes? Why not use nodes that is true adn correct?



  • "Mean Nodes" = using the method of arithmetic mean or midpoint within a statistical range to predict the location of Rahu-Ketu. It is not a character judgment!
  • "True Nodes" = geometrically logical triangulation of fixed points to predict the location of Rahu-Ketu. It is also not a character judgment!

Most modern, computer-using, astronomically literate Jyotishi prefer to use the statistical-mean method to calculate upagraha, as due to their irregular tendencies a logical-true model quickly becomes inaccurate.

However traditionalists who were trained by a guru-master using a memorization method of Jyotisha-learning without benefit of computerized rapid calculations (nor of critical thinking) may not be aware of the astronomical complexities of measuring the irregular trajectories of Rahu-Ketu.

Further, they may presume that the adjective “true” means accurate or correct or perfect -- whereas “true” in this context simply indicates geometrically logical.

But the movements of Rahu-Ketu are not fully logical. Their trajectories have certain illogical properties which are better accommodated by a statistical model (the arithmetic mean).

So although some are still using the logical-true method because it is geometrical and thus easier to calculate by hand than a statistical range midpoint (and it was the only known method in older times), the logical-true model does not consistently support observed data and thus the statistical-mean is a better way of matching the actual observed movements of Rahu-Ketu.


Respected Madam, Namashkar,

There is confusion in Rahu's Degree and Nakshatra in my chart. In India few softwares are stating 26:16 degree,while some are stating 27:15 degree, The problem is tht due to small change in degree of Rahu, it's Nakshatra is changing moreover the divisional signs in Varga are changing ie. in case of 26:16 scorpio Navamsha and in 27:15 Dhanu Navamsha.

According many calculations are going wrong, I don't know how they are calculating, but this small error is making big difference in results.

Major error would be In dazamamza-10 , where instead of 4 planets occupying the Kendra, will be only 2( Sat and Mars), Big concern for my Fame of National and International question.

How to confirm the exact Degree of Rahu on 7th Jan 1979. 21:07 pm Lucknow India.

A:'Mean' vs. 'True' Rahu: a Jyotisha calculation choice

Namaskaram, the astronomically correct degree for upagraha should be determined by the arithmetic mean position, which is a calculated midpoint within a statistical range = "Mean Rahu ."

Conflict of Opinion within the Jyotisha Community of Practice

There is an interesting discussion involving several international Jyotishi on this page

  • If you follow even this brief discussion, you may observe that there is no consensus among Jyotishi, and that significant conflict on calculation points is acknowledged within the literary traditions of Jyotisha (North/South, guru/pandit, various editions of the Sanskrit/Tamil classics, etc.)

  • I agree with the Jyotishi who says "you have to use what works for you" in terms of predictions. In practice, I agree with Sanjay Rath in this particular matter. (I do not agree with him in all matters however!)

Resolution through"Intuition First"

Congratulations: You have discovered something very important in the practice of Jyotisha!

  • It is absolutely necessary to meditate upon the nativity first , before attempting to predict solely upon numerical calculations.

  • The Vidya of Jyotisha is a whole brain knowledge base. That is, both left brain and right brain must be engaged and interacting constantly in order to make consistently accurate predictions.

Rational vs. Intuitive components of Jyotisha Reading

There are actually two separate types of knowledge processed during a Jyotisha analysis and prediction.

Rational Analysis

The rational analysis is essentially an array search of a rather large table of mathematical items and their human-life descriptors. This table of correlations is huge. Computers of course help these searches immensely.

Unfortunately a computer "dump" of all possible results of major and minor configuration items in a nativity is almost useless, because it is both too large to digest and it contains so much contradiction.

The more classical, traditional literature one consults, the more contradiction one discovers. How to make sense of this ocean of conflicting predictive information in the texts?

Intuitive Perception

The way to clear up the rational mess and to simplify one's search for meaningful predictive indicators is, IMO, to meditate briefly upon the nativity . In a meditative state the Jyotishi can receive guidance on central patterns to look for and how to frame the response to the client to that it is best pitched to their level of awareness.

Divinations are delicate operations, both intellectually and socially. Whether they admit it or not, most people rely on divinatory predictions to set their life expectations and to make important life choices.

Their divinatory practice may be personal prayer, seated meditation, taking long walks in nature, reading holy books, or recording their dreams. Everyone seeks divine guidance in some way.

Many people seek guidance from astrologers. This is a heavy responsibility for practicing Jyotishi! Not only do we Jyotishi have the ego motive o make accurate real-world predictions (that is fun and very rewarding intellectually!) but we also have a spiritual motive o channel the greater good through our predictions. We all want to live in a better world. The Jyotishi who can help raise individual consciousness of karmic law and encourage compassion for Self and others via good predictions, is helping the world toward a better state IMO.

The Jyotisha must first establish a spiritual attunement , then proceed in a grounded mental state, with caution and respect, ideally remaining open to divine guidance during the reading or evaluation.

The practitioner will find that predictions are much improved by firstly entering a state of awareness of the native 's astral qualities and current needs.

Secondly one should engage the rational intelligence to begin a process of pattern recognition which can sort out the relevant factors from the less relevant background data.

The astral picture, obtained in meditation, is not produced by rational calculations. It is composed of light, color, texture, heat/cool, sound, and other sensual qualities. It is a bit like watching a dream-movie, or putting on a "virtual reality" headset. The astral picture gives the Jyotishi a psychic impression of the native which is then applied as a filter and guiding framework to emphasize dominant influences.

Combining Intuitive Guidance with Rational Calculations:

The Jyotisha whole-brain judgment process happens pretty quickly, and often the two components are so intermixed that they appear to be working simultaneously. But it is important to realize that the intuitive information was in place FIRST.

For example, your own nativity is very striking: Shani-yuti-Rahu in lagna in an extremely hostile rashi - the social identity is in chaos. This native does not easily find his place in society. It is the mark of either insanity(tantrik carryover from Rahu) or genius(breaking social taboos from a position of moral leadership) or both.

The astral impression is red and black, with flashing lights and loud noises of crashing but also wide smiles of intelligence and excitement. Clearly the native has chosen a lifetime practice of encountering and negotiating conflict. There is a famous French novel Germinal 1840-1902 Emile Zola. It tells about the violence and brilliance of social conflict in 1860's northern France. This book and its qualities comes to my mind, because of my own life path, when I meditate to estimate the intensity and scope of the nativity.

This is just a small, incomplete example of the astral picture which arises in meditation. It is offered for the purpose of establishing a practice skill.

Making accurate predictions using possibly inaccurate calculations :)

After the astral picture is detected, one is better positioned to negotiate calculation conflicts. Clearly Rahu is a major, major player in this nativity. Predictions related to Rahu Mahadasha are mission-critical for setting the native 's appropriate expectations of himself and his own performance.

And also, when a client shows a powerful Rahu, there is no doubt of one's tremendous hunger for intense experiences both 'easy' and 'difficult'. This native in particular MUST develop their own internal guidance system based on tantrik communication with Divine Intuition.

Making Choices in Jyotisha -- and Human Life in General

OK, that was a long lead-up to what I must say regarding Mean versus True calculations for Rahu. If you have a doubt about which version of the Rahu calculations is correct for you and your path, there are four things I wish to mention:

  1. Good for you! You have discovered an area of volatility and disagreement in Jyotisha tradition. This awareness that you now possess will prevent your becoming superstitious or relying unduly upon outside opinion

  2. The unique nature of your Rahu indicates profound tantrik capabilities . As you may know from studying traditional village shamans (or modern shamans such as macro-economists!) being a Shaman is a dangerous social position. It is easy to be run out of the village with burning torches. So you, above all people, MUST develop your internal guidance system, which means making the commitment to remain in a state of conscious 'background' awareness, even when you are actively engaged in the world. You have to check that inner radar screen constantly , to avoid getting into trouble with Rahu-related disabilities such as impulsive marriages and illness from pollution (both spiritual and physical).

  3. In order to choose which of the Options for Rahu (Mean versus True) you will use , you will need to run the calculations both ways, and look at the two sets of results. Which set of results better matches your astral picture? In a meditative state there is no anxiety or rational mind-spinning. You can just look at the picture. Do this first. Then run both sets of calculations and see which one matches your INTUITION.

  4. This Rahu issue is important not only for your ability to use your Jyotisha charts as a reliable life guide, but also for your life practice in other areas of human choice-making behavior. I hope this situation can serve as a moment of life orientation, when one is forced to learn that intuition and logical reasoning should operate together as much as possible, but that intuition must come slightly first. Always honor your intuition. Intuition or the"inner teaching" is a channel for divine guidance.

Sincerely, Barbara Pijan Lama, Jyotisha


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