Precession and the sidereal zodiac

Hi all. I've started this thread to try to get some clarity about the sidereal zodiac, after finding conflicting information. My understanding was that the Indian government, at some point in the 20th century, tried to homogenise the practise of vedic astrology in India by citing the original Babylonian 12 sign sidereal zodiac as the true sidereal zodiac, calling it the Lahiri zodiac.

If the great year is 25,868 years long, then the vernal point moves at about one degree in 71.9 years. Solar Fire gives the current difference between tropical and sidereal positions as about 23 and a half degrees. This means that the tropical and sidereal zodiacs would have coincided around 320 C.E.

But some sources seem to be claiming that the original sidereal zodiac coincided with the tropical zodiac in 100 C.E. I know that there are various ways of locating the sidereal zodiac along the ecliptic, and that it can be divided by irregular constellations as well as equal signs. But there was surely only one original Babylonian twelve-sign sidereal zodiac.

I would be grateful if anyone could shed any light on this. Many thanks,

miquar said:

Hi all. I've started this thread to try to get some clarity about the sidereal zodiac, after finding conflicting information. My understanding was that the Indian government, at some point in the 20th century, tried to homogenise the practise of vedic astrology in India by citing the original Babylonian 12 sign sidereal zodiac as the true sidereal zodiac, calling it the Lahiri zodiac.

If the great year is 25,868 years long, then the vernal point moves at about one degree in 71.9 years. Solar Fire gives the current difference between tropical and sidereal positions as about 23 and a half degrees. This means that the tropical and sidereal zodiacs would have coincided around 320 C.E.

But some sources seem to be claiming that the original sidereal zodiac coincided with the tropical zodiac in 100 C.E. I know that there are various ways of locating the sidereal zodiac along the ecliptic, and that it can be divided by irregular constellations as well as equal signs. But there was surely only one original Babylonian twelve-sign sidereal zodiac.

I would be grateful if anyone could shed any light on this. Many thanks,

Click to expand...

Approximately 285 A.D. BOTH sidereal AND tropical ephemeris indicated the Sun's ingress into Aries at the Spring equinox as occurring SIMULATANEOUSLY for each zodiac

Both systems observe celestial phenomena BUT from different vantage points.


Western astrologers orient planets according to the seasons


Vedic astrologers orient planets to the fixed stars.

VISUAL OF THE DIFFERENCES BETWEEN SIDEREAL AND TROPICAL http://www.youtube.com/watch?v=82p-DYgGFjI&feature=related


EXAMPLE

In approximately 11,200 years, at spring equinox,
Sun will be at 1st degree of Libra due to precession of the equinox
exactly opposite TROPICAL zodiac

SIDEREAL PERSPECTIVE

Thanks Jup. So is that based on the Lahiri sidereal zodiac? And was this the original Babylonian sidereal twelve-sign zodiac?

Do you know why someone might consider the coincidence of the zodiacs would have occurred at 100 BCE ?

Thanks again,

Strangely the source that gave 100 BCE was Nicholas Campion in A History of Western Astrology.

Do you know about the other questions in my last post.

Thanks for taking the time to post on this thread.

Remembered book title wrongly. Should be: An Introduction to the History of Astrology.

There have been several coincident dates determined by various authorities:

-Gould et al, researching Hipparchus, gives the date 120 BC
-Magregor Mathers, (allegedly) working from "original" ancient esoteric material, gave 90-94 BC as the date
-the little known Alcyone/Pleiades ayanamsa gives 144 BC*
-historian Professor Whitney and co-research/astronomers at Yale University and Harvard University, gave (back in the late 19th century) 420 AD (see eg Richard Hinkley Allen's "Stars Names: their Lore and History')
-Vivian Robson estimated 500 AD
-B.V. Raman, using various original Indian (Vedic Astrology) sources, gave 387 AD

Based upon my studies and "experiments" regarding this subject, I strongly lean to the earlier dates: note that Campion's date-100 BC (if he gave that date rather than 100 AD or CE!)-is very close to the Hipparchus, Mathers and Alcyone/Pleiades dates, all 4 dates-each coming from very different sources-are within a 50 year period of time of each other.

The discussion between AquarianEssence and I, on the 2nd and 3rd pages of the thread entitled "The Age of Aquarius", might be of some interest regarding this subject...

(*using this date, and precessing @ 50.35 seconds per year-a rate used by some astronomers {others use 50.24 seconds per year} the Vernal point would have entered the last degree of Aquarius in the spring of 2001)

Many thanks. So could someone confirm that the Lahiri zodiac is the same as that used in Babylon when the zodiac was first divided into twelve signs?

miquar said:

Many thanks. So could someone confirm that the Lahiri zodiac is the same as that used in Babylon when the zodiac was first divided into twelve signs?

Click to expand...

A link/stating the source of the above quoted assertion would be helpful. In the meantime an acknowledged currently living expert on this subject is rumen kolev who provides an an email address at http://www.babylonianastrology.com/

Hi. I can't remember where I came across the idea that the Indian government chose the original Babylonian zodiac to be the Lahiri zodiac. But according to Robert Powell, in History of the Zodiac, the Babylonian sidereal zodiac was coincident with the tropical zodiac in 220 C.E and so the vernal point is now at 5 degrees Pisces of this zodiac. Whereas the vernal point is currently at 23 and a half degree of the Lahiri Zodiac, and so the Lahiri and tropical zodiacs must have coincided at about 320 C.E.

You gave 285 C.E. as the year of coincidence, so what sidereal zodiac is this based on? The vernal point must be at 24 degree of this zodiac.

Isn't there some difference between the different sidereal ayanmshas, and aren't those differenced based on which precession rate, as well as start date each uses? miquar, is that what you are trying to figure out, what is the start date for precession? Or are you trying to find the exact time the two zodiacs aligned?

I don't know if it helps or not, but for some reason many of the western traditional siderealists of whom I'm aware use (I believe dr. farr has also said it produces the best results, though he uses the tropical zodiac) Krishnamurti.

Is this for the same book/idea as the 8 house system? If so, have you tried posting the question to skyscript? I believe there may be members there who could also help.

Yes there are significant differences between the various ayanamsa's; also I personally am unaware of any connection between the Lahiri figure and the Babylonian zodiac (actually Babylon had-as I remember-about 26 constellations grouped about what we now refer to as the ecliptic)

The various ayanamsa's (and of course, only 1 could be objectively correct in a scientific sense) are based on the estimated date for the Vernal point's entry into the boundaries of a zodiacal constellation (NOT a SIGN-the actual starry constellation) Problem with this is the various boundaries allocated by various historical cultures to each zodiacal constellation. Also, when referred to the ecliptic, the constellations often overalp, because the 12 zodiacal constellations are of variable size (longitudinally considered)-they each DO NOT cover exactly 30 degrees of longitude (eg Gemini covers 22 degrees of longitude, while Aries covers 33 degrees-these figures based on the historical Western zodiacal boundaries, not on these boundaries as fixed in the 1930's by the International Astonomical Society)

To find the current ayanamsa, you base the calculation upon the date of Vernal point (alleged) co-incidence with the starry zodiacal constellation's LAST POINT, then
a) if the date is AD, subtract this date from the current date, multiply by 50.24, then divide by 3600: this gives the # of degrees to be subtracted from the current tropical degree position
b) if the date is BC, add this date to the current date and do the same calculations as above.

Hi. Thanks everyone.

Jup - thanks for interesting link. I was really asking about different sidereal zodiacs, as tsmall says. Your figures are quite confusing, since if there is a 23.5 degree difference between the tropical vernal point and the first point of Aries in a sidereal zodiac, then the tropical vernal point will be at 6.5 degrees of that sidereal zodiac. To approximate this to 5 degrees changes the year of alignment between that sidereal zodiac with the tropical zodiac by around a century.

Hi tsmall. Yes I'm still writing that same book. I decided in the end that the only sufficiently established 8-segment cycle of position is the lunation cycle, so that's the one I'm using to compare the archetypal differences between 8 & 12-fold division of the circle.

I also would like to look at the history of the tropical zodiac, and so am trying to get a sense of how the different stages of awareness and use of this zodiac tie in with the zodiac alignment. It would seem appropriate to use the sidereal zodiac of the day for this, which puts alignment within about one degree at the time that Ptolemy wrote Tetrabiblos, reaching perfect alignment in 220 C.E. However, from what I can gather, the Lahiri zodiac was aligned with the tropical zodiac about 100 years later at about 320 C.E.

Given these dates, I was confused about why Campion would suggest 100 C.E. as the approximate year of alignment. Which sidereal zodiac might he be considering, I wonder?

Hi dr. farrr. Do you know if the Babylonians moved the first point of their sidereal Aries when they began to use 12 thirty degree sidereal signs rather than 12 irregular constellations?

I guess that since the ayanamsa refers to the angle of arc along the ecliptic which separates the tropical vernal point from a proposed first point of sidereal Aries, then it could be applied to a sidereal zodiac based on either signs or constellations. I believe the astrological ages are often thought of as being of equal length to one another, which implies that the vernal point is being tracked along sidereal signs.

Which sidereal zodiac has been adopted as the Lahiri zodiac? It can't be the original Babylonian 12-sign zodiac as this gives a 25 degree ayanamsa (according to Robert Powell), whereas the Lahiri gives 23.5

Hi again. I've rooted around some more and have found some clarity, but one thing doesn't add up still.

The original Babylonian zodiac is said to have an ayanamsa of 24.9 degrees (because it is said to have coincided with the tropical zodiac in 220 CE, and based on 72 years for one degree of precession).

The lahiri zodiac has an ayanamsa of 23.5 degrees and it is widely mentioned that this zodiac coincided with the tropical zodiac in 285 CE. But using the precessional rate given above, the ayanamsa has moved 23.5 degrees since about 320 CE.

The difference in dates of coincidence of about 100 years fits perfectly with the difference of 1.4 degrees between their ayanamsas.

On the other hand, the Babylonians supposedly had 0 Spica at 29 degrees and a few minutes of Virgo, while the Lahiri system places it at 0 degrees Libra. This difference of almost one degree concurs with a difference of around 70 years between the respective dates of coincidence with the tropical zodiac.

Does anyone know why this doesn't add up? It could seem that the figure of 285 CE must be wrong because the Lair ayanamsa is 23.5 degrees. But then again, why are these two sidereal zodiacs said to be just under one degree apart?

miquar said:

Hi. Thanks everyone.

Jup - thanks for interesting link. I was really asking about different sidereal zodiacs, as tsmall says.

Your figures are quite confusing, since if there is a 23.5 degree difference between the tropical vernal point and the first point of Aries in a sidereal zodiac, then the tropical vernal point will be at 6.5 degrees of that sidereal zodiac.

To approximate this to 5 degrees changes the year of alignment between that sidereal zodiac with the tropical zodiac by around a century.

Click to expand...

You mentioned a figure of 23.5 degrees

miquar said:

....the Lair ayanamsa is 23.5 degrees.

Click to expand...

That was probably a typo and you obviously must have intended to write 'Lahiri' as you then said on your next post

miquar said:

....whereas the Lahiri gives 23.5

Click to expand...

Definition of ayanamsa http://en.wikipedia.org/wiki/Ayanamsa


By the way,

remember that precession 'goes backwards'


SO


then using your given suggested figure of 23.5

WHEN COUNTING BACKWARDS FROM Tropical Vernal Point 0º Aries FOR SPECIFICALLY 23.5º

THIS IS HOW WE COUNT BACKWARDS SPECIFICALLY FROM Tropical Vernal Point 0º Aries FOR 23.5º

i.e.

0 Aries
-----------------------------------------------------------------
29 Pisces last degree
28 Pisces penultimate degree
27 Pisces and so on counting backwards
26 Pisces
25 Pisces
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
09
08
07
06 Pisces
05 Pisces


HOWEVER KEEP IN MIND THAT THESE ARE APPROXIMATIONS

'....The ayanamsha describes the gap between tropical and sidereal zodiacs

AND CHANGES CONTINUALLY through the Precession of the Equinoxes

at the rate of approximately 50" a year,

and is currently APPROXIMATELY 24° (Lahiri).


But traditionalists in India put the current value at about 22.6 degrees which is the value according to Suryasiddhanta and Raman's ayanamsha approximates it while Yukteshwar ayanamsha is almost exactly equal to Suryasiddhantic ayanamsha.

Western Astrologers Fagan and Bradley computed it at 24 degrees in 1950; however, there are various values in use in India.....'

'.....While the general consensus among Western siderealists is that the star Alcyon represents the first point of Aries, differences arise because of the indefinite ancient boundaries of the constellation of Aries. Indian definition of astrological signs is not based on constellations but on equal angular division of sky, which makes it difficult to define signs in terms of stars and constellations. This is the source of controversy about ayanamsha......'

Hi Jup. Lots of patronisingly obvious points there, but no explanation as to why 30 - 23.5 = 5

miquar said:

Hi Jup. Lots of patronisingly obvious points there, but no explanation as to why 30 - 23.5 = 5

Click to expand...

Apologies

23.5 is a figure you mentioned on your OP

So I've focused on that

Counting backwards from zero Aries
one gets to an approximation of the current ayanamsa

This is because the precise ayanamsa varies according to which authority one consults

Some say 23.5 some say 24 others claim some other figure and so on http://en.wikipedia.org/wiki/Ayanamsa

The tropical zodiac DOES account for precession.

Sideralists who claim that only the sidereal zodiac accounts for precession should check their logic circuits.

The two zodiacs account for precession in two different but equally valid ways.

The tropical zodiac allows for determination -- by observation -- of the vernal equinox (0 degrees Aries by definition in that system) during any year.

The sidereal zodiac (claimed as the Only True Zodiac by some) is not based on any verifiable fact. Period. How many ayanamsas are there? A dozen at least. In which year did coincidence actually occur? No one knows. The precessional period is not regular; it has slight variations, sometimes caused by such minor perturbations as an earthquake (Concepcion). Where is "zero Aries" in the constellations? That point is purely arbitrary, unlike the vernal equinox.

It should also be noted that the Earth is not fixed in space. It apparently revolves around the Sun, the Sun (and solar system with it) around Sirius, and that complex around the galactic center. Therefore the insistence on using Earth's relationship to fixed stars (that are not fixed) is spurious.

If the scientific standard for theories and mathematical models called Parsimony (also called Occam's Razor) informs us how to judge the validity of theories and models, then the tropical zodiac wins the contest, because the tropical zodiac describes earth's relationship to the cosmos in a simpler way. The sidereal zodiac depends on the fixed stars (which are not fixed in the first place), while the tropical zodiac works perfectly without them ever appearing in the sky. With the tropical zodiac we could create the signs as they exist today without ever having seen a star shine. This is not true for the sidereal zodiac.

If our astrology is geocentric, and the art deals with people who live on the Earth (they are also geocentric), then an Earth-centered system of measurement (determination of the vernal point) is appropriate. It does not rely on far-distant stars as its frame of reference.

It seems to me absurd to put Capricorn in the middle of summer (totally out of character for the sign's significance), which is what the sidereal zodiac does during a lengthy period in each precessional cycle. Capricorn is always a winter sign in the tropical zodiac.

We should keep in mind a very elementary fact. Constellations and signs are not concrete facts, but are constructs of man's mind. They have no substance in reality. The entire fabric of astrology is a construct of man's mind. The reason it works is because man's mind, like the solar system itself, is one with the all. Physical laws that are valid on Earth are also operative in the farthest reaches of the universe. And this also applies to non-physical laws. An example of a non-physical law is the Law of Karma, whiich careful observation of life will show to be true and consistently effective. This same underlying law can be expressed as a physical law, stated by Newton as "For every action there is an equal and opposite reaction." It can be stated also as "Whatsoever thou sowest, that also shall thou reap." These laws hold throughout the universe.

The constellations (and individual stars within them) were man's first points of reference for locating the wandering stars (planets) in the sky. The signs evolved out of the constellations as man began to apply mathematics to the natural world around him. But the constellations themselves are mental constructs. I "see" a scorpion by connecting the dots. An image (and a correlation, an analogy) is what creates the scorpion...not something inherent in the stars themselves.

Thus, man's mind functions according to this universal scheme, and his capacity for analogy (which is the basis for astrological symbolism -- including constellations and signs) is in harmony with the nature of the cosmos in any of its expressions. That is why astrology works.

I use the tropical zodiac. But I have absolutely no objection to the sidereal zodiac (pick the one you like best; sadly for me and my ilk, there is only one tropical zodiac). My only objection stems from the false claims of the more fanatical siderealists that theirs is the One True Faith. I can't recall ever seeing a tropicalist trying to proselytize the way many siderealists so often do. "The lady doth protest too much, methinks."

Miquar, I don't think your question has a definitive answer. The variations in the precessional cycle (period) can only be determined by observation, and are not precisely predictable in the abstract. What is past and unobserved is lost. There are, I believe, at least 4 or 5 causes (forces that influence and affect) for Earth's nutation, and slight variation in any one of them affects the precessional period. As mentioned, unpredictable events such as large earthquakes add their grain of sand to the pile as well.

Yes, thanks Greybeard. I guess I just wanted some clarity about why the figures in my last post don't make sense. Everyone seems to use a value of one degree in 71.5 to 72 years for precession, and so that inconsistency shouldn't be there, unless I'm missing something.

I didn't know that the Sun revolved around Sirius. Presumably someone has checked to see if there is a nodal axis at the intersection of the ecliptic plane and the plane of the Sun's orbit around Sirius, to see if it comes out anywhere near one or more of the proposed sidereal first points of Aries.

I was reading something today about the way in which vedic astrology is taught and how it is defended with religious fervour because it is entwined with the teaching of the vedas, and also that in fact vedic astrology was only given that name in the eighties, and astrology was not originally a part of vedic teaching anyway. I'll post the link in a separate post.

Another thought is that the twelve sign sidereal zodiac was established when most of the original sidereal sign of Aries was in tropical Aries. So this could have influenced the observations and associations made.

Hi Jup. I took the 23.5 degree figure from Solar fire, and was just question why you would place the vernal point at 5 degrees of Lahiri Aries rather then 6.5 degrees.

I have many doubts about the astrological ages, and am more interested in the apparent transit of the galactic centre through the tropical zodiac. And now I'm also interested in the apparent transit of Sirius. The ancients wouldn't have known that Sirius has a special relationship to Earth, but I'm now curious about where it 'landed' with regard to the first 12 sign zodiac.