MarkC wrote:I have seen a few posts here on skyscript suggesting that that the zodiac used by the Greeks and Romans was basically sidereal before the ideas of Hipparchus and Ptolemy became widely accepted.

As (insofar I believe) precession was unknown before Hipparchus I don't think we should think in terms of 'tropical or sidereal but rather 'tropical and sidereal'. Since precession was unknown I think both sidereal and tropical was used. In Mark's link to the article of the parapegmata many times the positions of the stars throughout the years are used as markers for the seasons. While many believed that the stars like Sirius in Canis Major caused the heat of the 'dog days'/caniculare, Geminus of the 1st century BC already rejected that view.

As the article makes clear there was considerable confusion in the classical era where the vernal equinox lay.

In fact most astrologers seem to have worked on the assumption that that the vernal point was either located at 8 or 12 degrees Aries throughout the classical era.

There no fixed star as the marker of the zodiac. In all cases the vernal equinox was the reference point for the zodiac in the Greek and Roman astrology. Hellenistic astrology was always tropical.

In Christopher Walker's 'Astronomy before the telescope' he stated that the Babylonians Beta Geminorum/Pollux in Gemini - 90? was used as starting point when the Babylonians just had made the signs equal in the 5th century BC.

According to this Astrodienst article (referring to cuneiform texts and horoscopes) http://www.astro.com/swisseph/swisseph. ... c226863952
the Babylonians used a zodiac closely related to the position of Spica-180?.

I've been thinking why the choice would have been this star. They could have chosen another not too weak star in Aries, Beta and Gamma for example or Eta Piscium.
Here some speculations:
- If a full Moon would occur in conjunction with Spica then the star too would be in opposition with the Sun, making this an easily visible event.
- The stars Aldebaran, Pollux, Spica and Antares have very interesting positions their mutual ecliptical distances are all very close to plurals of 45?, so using Spica (or another of these) as a reference would almost always give another visible reference star easy for calculations.

Equinox at 8?,10? or another degree? And why?
- Perhaps the position was set in different periods without recognizing precession and believing a mistake was made. Spica was in the autumn equinox in the 3rd century so about 7 centuries before the spring equinox was considered to be at 10? of the zodiac. .... why not using the equinox itself?
- Maybe for the conveniance of the use of the other bright stars mentioned above.
- The cause of the climate/weather may not yet have been properly understood.
- The calendar was luni-solar with intercalation every two or threee years. This makes the starting point of the year between the stars shift. It seems plausible to me to think that the earliest starting point would have been some degrees before the equinox point. Moreover this point is abstract and 'invisible' in the sky so maybe not so appealing.

Deb wrote:

MarkC wrote:Hello Wolfgang,

The subjec here is Hellenistic zodiac, but because here is also a link to the Zodiac History, I will tell you, that the old Babylon did know the Precision 1000 year before Hypparch.

Thats a very controversial view. It hasn't had the support of any academics for over 60 years as far as I am aware. I cannot say with personal authority that makes this view wrong. Academia has its fashions too. However, at present such a view is definitely very 'alternative' and not highly respected by any authorities in this field of study.

I don't think it is so controversial nowadays, and there seems to be some respect for the view that the principle of precession may have been understood by the ancient civilisations, and is suggested in the alignment of their temples.

Respecting 'controversial views' I too though tend to be very carefull and rather believe that Hipparchus was the first one to recognize precession. Here's an article I found a while ago, which happens to be of Gary Thompson http://www.members.optusnet.com.au/~gto ... age9f.html
Where it is true that in ancient times temples were built according to star(rising/setting) positions, like Teotihuacan/Mexico orientation to the Pleiades, this doesn't convince me that the people who built them knew precession. The later generations may simply have forgotten the meaning of some positions of buildings.

There is no doubt in my mind that this exists. And of course, it is just philosophically ugly that the signs of the zodiac do not relate directly with the constellations! During my frequent, bumbling attempts to identify the stars that I can see, I am often trying to imagine everything one sign away from itself, so that what I know of a chart can be related to what I see in the sky. And the worst is yet to come, because at some stage we are going to be talking about the sign of Aries roughly overlapping the constellation Libra.

Being with Kepler and paying less attention to houses and signs, I don't really have a problem with that. Even some 2000 years ago when the signs (almost) coincided the fact that the signs were 'equalized' to 30? sectors made that the Scorpion lost his tail to Sagittarius and his claws (changed in)to Libra (talking about mutilation ), one of the two fishes cut in half and even the Twins might be separated.
And to make matters worse, in say 100,000 years from Ptolemy or after four 'Platonic years' we might expect the constellations to 'click' in eachother again, but as the stars have 'proper motion' many constellations will be unrecognizable to us. Because of this I don't really feel attracted to astrology based upon the symbolism of the 'pictures' of the constellations, moreover other cultures saw different things in the stars.

I can imagine that the ideas of precession weren't accepted by some. It was revolutionary. Even 300 years after Copernicus there were astronomers who taught the geocentric Ptolemaic system at universities.

As observation proved that there was a movement, a sort of 'compromise' was proposed by Theon of Alexandria in the 4th century CE. Trepidation. this was the theory that the equinoxes went back and forth around a fixed point in the sidereal zodiac. http://adsabs.harvard.edu/full/1972JHA.....3...27P
http://articles.adsabs.harvard.edu/cgi- ... etype=.pdf (this one is in French but has some illustrations). The Indian astronomers who already had based many calculations on the sidereal year/zodiac didn't want to give that up and start all over again and accepted this theory.

trevor wrote: the Shaffer play, or discussions surrounding it, that they fought but underneath was this resignation to their fate.

That doesn't sound so crazy, but I don't know enought about their culture to say for sure. The people from my native background didn't get conquered.

trevor wrote: You say you have read the Sullivan book so is the Amazon review misleading and/or do you think this astro-archao narrative is erroneous as regards the Incas? I'm struggling to follow your thinking here.

Probably more the review then anything, if anything my thinking is at the same point as Mark's: that one should read this book again.

Being with Kepler and paying less attention to houses and signs, I don't really have a problem with that.

Hi Eddy,

This is just a side issue really, but it is something I am curious about. You have mentioned on several occasions that you follow Kepler and so you don't really use the signs or houses. But I wonder if you have actually followed the techniques that Kepler applied in his astrological work? I know that Kepler questions the the reality of, say, the houses, and speaks out against them having an objective reality, but from what I understand, when it comes down to the judgement of the charts he drew for himself and his family, he took just the same approach to the judgment of a chart that was typical of his contemporaries - houses, signs and all. My belief is that he questions the validity of signs and houses as astronomical concepts, but he simply accepts their traditional role when it comes to astrological practice. I wonder if you have any views on that?

Deb

Hello Mark,

MarkC wrote:Hello Gabe,

While the idea that precession was known among ancient civilizations is important in the book, IIRC it is more focused on the idea that all of world mythology was encoded in the same fashion

Its been a few years since I read the book too and you are convincing me I better re-read it! I hadn't really got the impression he was emphasizing a global dissemination of the same images. The chapter that really struck me was actually about Paleolithic and Neolithic cultures and how their astral beliefs was originally integral to their hunting and gathering lifestyle.

Well, I was talking about the implications of Hamlet's Mill, though Sullivan in his book does use this to, I think, great effect and even describes the basic idea. I have to agree with most of what you have said, it is quite clear that "primitive" peoples did quite a bit with their knowledge of astronomical lore. I like to think of it as the original information system.

We have gone away from the original topic, haven't we? But it is one of the themes of Plato that we are constantly trying to remember what was forgotten.

Deb wrote:But I wonder if you have actually followed the techniques that Kepler applied in his astrological work? I know that Kepler questions the the reality of, say, the houses, and speaks out against them having an objective reality, but from what I understand, when it comes down to the judgement of the charts he drew for himself and his family, he took just the same approach to the judgment of a chart that was typical of his contemporaries - houses, signs and all. My belief is that he questions the validity of signs and houses as astronomical concepts, but he simply accepts their traditional role when it comes to astrological practice. I wonder if you have any views on that?

Deb

Hi Deb,

These are good questions and makes one think. Kepler's use of houses and signs at first would appear like a prominent AA leader who drinks alcohol.

It's quite difficult to tell how I came to it. Different factors play a role in it. I think it partly came from the fact that some 14/15 years ago the only books on astrology I found were the esoteric and psychology astrology books I wrote on this in the Saturn Uranus thread http://skyscript.co.uk/forums/viewtopic ... 7&start=30 (perhaps in a bit sarcastic way but) I never liked that approach that seemed to fit to everyone. Another factor closely related to the first one is that I also was interested in the view of scientists or opponents. Many issues in psychological astrology can be explained by effects like 'cold reading' etc. As many of these psychological issues were related to the houses, it therefore was 'easy' to fall for Kepler's 'scientific' view. I've been an amateur astronomer since I was 10 and only started astrology at age 24/25. Kepler therefore was also familiar to me as a good astronomer.
In those years I had the idea that since character delineation is easily subject to psychological effects, I decided to put astrology to a 'test' with 'prognostication' by checking my moods during transits. As these 'worked' I then was convinced by the effectiveness astrology.
Another issue is the contorversy over which house system is the 'correct' one. From a technical point of view I probably would choose an equal ecliptically based house system with the MC as main reference (with result that the Ascendant can be in other houses and not being cusp I).

I did look in the 'recepies' for planets in houses, some are true (I must admit that my Saturn in II can point out such financial matters) others are too vague. But I never really researched my or family/friend's chart with houses, signs in a deep say Morin method way. So most of my opinions/objections are theoretically based. I have a problem with the use of the usual tropical signs on the southern hemisphere and moreover I feel most for the geometrical approach and therefore question the idea of 'sectors' of influence rather than 'points' like the Ascendant and MC.

About Kepler's use of the 'usual' methods I think it can be explained with several points. Perhaps I'm a bit 'explaining away' over here filling in some assumed reasons because I'm not sure if they are true.
First I think that in his young years (till 1600) he mainly would use the normally accepted methods. In this interesting article http://cura.free.fr/docum/15kep-en.html here are some translated quotes with the year in which he made them. There is also an interpretation by him on his own chart from 1597. In this article (which unfortunately can only be read when in a university library or when paying for it)http://www.jstor.org/stable/3039261?&Se ... howArticle
Kepler's change of ideas of the opponent of astrology Pico is discribed.This probably occurred somewhere between 1600 and 1605. I actually don't know if he brought his theories in practice on the horoscopic level in later years. Maybe he found out that several things weren't correct. In the cura.free link ?3, Kepler stated that he also rejected the astrological use of houses (1606) not only as astronomical concepts. And his view of the signs ?4 is not really positive either, but I think he makes some valid remarks there.

Another thing is that, since he sometimes depended on astrology for a living, he probably simply did what people expected him to do, make a chart with houses signs and do the interpretation. Perhaps a weak standpoint of mine but there is a story that before he wrote the delineation on Wallenstein, he first had asked the messenger to write something on Wallenstein's character. So he could interpret in 'hindsight'. I have no idea if he was a real good astrologer according to his 'customers', I don't consider myself a good one and my own experience is limited to friend's and family's and my own charts. I too need to see and know the person in question a bit, so although I don't really like the deep psychological aproach but it seems that I partly depend on it. Perhaps I'm mainly a theorist basing many thoughts on astronomy but that part too is very interesting and I think also essential

On the other side I'm not sure about Kepler's views on the minor aspects like Quintile and Bi Quintile. I think the semi-square and semi-sextile have some (weak ) effect but I think the 'major' aspects are the most effective ones. (Somewhere Kepler also has that view).

Hi Eddy

I am in danger of sending this thread seriously adrift, but thank you for that response. Could you please give the title of the JSTOR article because it went a little strange?

I think we should come back to this subject and give it its own thread some other time. That will also give me chance to get a bit more informed. I know of references to the personal charts he did after the birth and death of his younger son, born in 1607, which show him using standard technique. These are contained within private correspondence to a friend so he had no financial motivation, and the emotive nature of the correspondence shows that that what he said of the astrology came straight from his heart. But I am recalling details from a talk that Dorian Greenbaum gave about a year ago, so I need to check some details. I have a great deal of admiration for Kepler?s life and work ? and it is probably not appropriate to try to squeeze him into the Hellenistic zodiac thread

Hello Eddy,

Interesting post.

Eddy wrote:
As (insofar I believe) precession was unknown before Hipparchus I don't think we should think in terms of 'tropical or sidereal but rather 'tropical and sidereal'. Since precession was unknown I think both sidereal and tropical was used. In Mark's link to the article of the parapegmata many times the positions of the stars throughout the years are used as markers for the seasons. While many believed that the stars like Sirius in Canis Major caused the heat of the 'dog days'/caniculare, Geminus of the 1st century BC already rejected that view.

That seems a fair compromise taking all the evidence into account. Cyril Fagan?s position that the Mesopotamians didn?t really consider equinoxes and solstices in their astrology is not really credible. There is a mass of information from Archeoastronomy now available that confirms just about every society from the Paleolithic era onwards aligned sites to solsticial and equinoctial points. Equally, though fixed stars were also used for alignments too.

In Christopher Walker's 'Astronomy before the telescope' he stated that the Babylonians Beta Geminorum/Pollux in Gemini - 90? was used as starting point when the Babylonians just had made the signs equal in the 5th century BC.

I must check that reference out as I have that book. How definitive is Walker about this? From what I have read so far its very difficult to be authorative about these assumptions from the cuneiform tablets we have.

It seems plausible as you suggest that the Mesopotamians moved their fiducial star ( if they really had one) more than once. We know Pleiades was the original starting point of the Baylonian 17 constellation uneven zodiac on the 'Path of the Moon'. Taking either the Pleiades or the Castor/Pollux as the starting point it seems quite different from the Fagan-Allen-Bradley Zodiac used by western siderealists today? I think it is quite possible the ancient Mesopotamians used a fixed star as a reference for the equinoctial and/or solstice point. Hence the need for a changing fiducial star.

According to this Astrodienst article (referring to cuneiform texts and horoscopes) http://www.astro.com/swisseph/swisseph. ... c226863952
the Babylonians used a zodiac closely related to the position of Spica-180?.

Not sure I would call this quite an article! The writer only consideres 3 options for the sidereal zodiac fiducial star. We all know that there are several suggestions. However, its coming up very garbled in the link. Maybe I was not seeing it all properly.

However, whether the Mesopotamians had a fiducial star or not and wherever it was located what seems quite clear is that the Greeks never adopted one in their zodiac.

Why?

As far as Cyril Fagan was concerned it was because the Greeks in the Hellenistic age did not properly understand the cuneiform tablets they took from sites in Babylon. However, this point ignores the close intermingling of Greek and Mesopotamian cultures from the Seleucid period onward.

http://en.wikipedia.org/wiki/Seleucid_Empire

As I pointed out earlier on this thread Otto Neugebauer and H.B. Van Hoessen suggest a continuity of ideas in their book Greek Horoscopes:

Babylonian astronomy of the Seleucid period uses two different methods for the description of the Sun and related phenomena. These two ?Systems? , called A and B respectively find a continuation in Hellenistic astronomy.

So the question is did the Greeks somehow miss out the Mesopotamian fiducial star or did they on the contrary follow the late Mesopotamian zodiac of the Seleucid period exactly as Neugebauer and H.B. Van Hoessen suggest?

I am not denying that if we go back far enough into ancient Babylonia we find a zodiac with fixed star markers. The question I have though is what kind of astrology was being practised in late Mesopotamia? Its this period that really matters as this is the era when hellenistic astrology was formulated.

The question I have is how the dissemination of the Hellenistic zodiac to India leads to a sidereal zodiac based on a fiducial star? If as we have seen the Hellenistic zodiac never had a fiducial star where did the Indians get one from?

Could the Indian approach have been influenced by their ancient attachment to the sidereal lunar mansion system known as the Nakshakras? Clearly fusing these two astrological systems needed a reference point? For Indian astrologers encountering the Greek zodiac nothing could seem more natural than linking the new astrological system to their ancient astrological system based on sidereal marker stars.

Deb wrote:I think we should come back to this subject and give it its own thread some other time. That will also give me chance to get a bit more informed. I know of references to the personal charts he did after the birth and death of his younger son, born in 1607, which show him using standard technique.

Hi Deb,
Yes you're right, we can discuss Kepler's view in a later thread. Do you mean the Jstor article of Kepler and Pico? I noticed I couldn'open the link. Here it is again. http://www.jstor.org/stable/3039261?&Se ... howArticle

and here is the source reference information,

Kepler's Attitude Toward Pico and the Anti-Astrology Polemic
Author(s): Sheila J. Rabin
Source: Renaissance Quarterly, Vol. 50, No. 3 (Autumn, 1997), pp. 750-770
Published by: The University of Chicago Press on behalf of the Renaissance Society of America
Stable URL: http://www.jstor.org/stable/3039261

Interesting to read that he still used standard astrology in the later years. Could there be somethng on the internet about this what you mentioned?

Hi Mark,

MarkC wrote:Cyril Fagan?s position that the Mesopotamians didn?t really consider equinoxes and solstices in their astrology is not really credible.

If that was the case then Fagan's sidereal zodiac should at least start with the Pleiades. Further all sidereal starting points are close to where the spring equinox was two millennia ago.

I must check that reference out as I have that book. How definitive is Walker about this? From what I have read so far its very difficult to be authorative about these assumptions from the cuneiform tablets we have.

Unfortunately I don't have the book but saw it in a library some 100km from where I live now. But it is in the chapter on Babylonian astrology. He doesn't state it with material but rather mentions it shortly.

Not sure I would call this quite an article! The writer only consideres 3 options for the sidereal zodiac fiducial star. We all know that there are several suggestions. However, its coming up very garbled in the link. Maybe I was not seeing it all properly.

Those paragraphs are difficult to read because of the 'computer language' things in it, quite annoying. It mentions that the observations had been inaccurate. Walker's book also mentions that the Babylonian calculations were much less elaborated as their calculations of the Solar and especially the Lunar positions. The earliest horoscopes mentioned only that the planets where in this or that sign. Sometimes the Sun and Moon got places in degrees and somewhere in the 3rd century BC more horoscopes had degree positions for all planets. Resembling (and previous?) to this there was the use of 'normal stars' positioning a planet being so and so much degrees or 'cubits' from a certain bright star closest to the planet. Maybe they didn't build up their astrology entirely on one and only fiducial star, considering this only as a mathematical aid while focusing on the whole picture related to the visible sky.

The Astrodienst text mentions a method by Hipparchus, stating that 0? Aries rose when Spica sets (on the island of Rhodos). the result is close to Zeta Piscium, the star of Revati of the Indian astrologers. So it seems that the Greeks (although vaguely) did use a fiducial star. In a Dutch books of sceptics on astrology it is mentioned that the more mathematically inclined Greeks already calculated positions based upon the tropical zodiac and then converted to sidereal positions by adding the 8?. Looking at it this way, I can imagine that an original fiducial star easily would get 'forgotten' or ignored.

We know Pleiades was the original starting point of the Baylonian 17 constellation uneven zodiac on the 'Path of the Moon'.

I was thinking of the Rochberg article on rulerships we discussed in the other sidereal thread. In the 7th century BC the signs were not only of unequal size but the (12 familiar) signs had boundaries with left 'empty' spaces in between. I don't know what thes would have meant during this 'transition' period. Throughout the article the boundaries of a few signs are mentioned. A reference note refer to "boundaries of the ecliptical constellations appropriate
for the Sargonic period, see Parpola, LAS II Appendix
B, p. 385." This period must be early 7th century BC.
Gemini 54?-75?, Cancer 87?-92?, Scorpius 210?-224?, Sagittarius 230?-251? , Pisces 313?-353?
In an attempt to 'google' for the rest I came also to this thread where you mention Parpola two days ago . Unfortunately I can't find the rest.

Could the Indian approach have been influenced by their ancient attachment to the sidereal lunar mansion system known as the Nakshakras? Clearly fusing these two astrological systems needed a reference point? For Indian astrologers encountering the Greek zodiac nothing could seem more natural than linking the new astrological system to their ancient astrological system based on sidereal marker stars.

It appears so and it seems that that Hipparchus point / or the Revati star was used as 'zero'. Most nakshatras then 'fit' but Purva Bhadrapada and Uttara Bhadrapada are quite off. However note that like the original 12 signs the 27/28 nakshatras originally were of different length.

Hi Eddy,

Fagan's sidereal zodiac should at least start with the Pleiades. Further all sidereal starting points are close to where the spring equinox was two millennia ago.

Fagan, and Allen with final refinements by Bradley calculated Spica to be around 29 06' Virgo rather than at 00 Libra as in the Lahiri zodiac. This restores Spica to its ancient role as the alpha star of Virgo. This left Aldebaran at 15.00 Taurus. Of course the Pleiades run over several degrees. There is approximately 10 degrees between the alpha star Alycone and Aldebaran. The Vernal point of the Fagan-Allen-Bradley zodiac is at 05 Pisces.

http://www.ablairewart.com/ASTROLOGY/AB ... nation.asp

Unfortunately I don't have the book but saw it in a library some 100km from where I live now. But it is in the chapter on Babylonian astrology. He doesn't state it with material but rather mentions it shortly.

I have no such excuse. I was just being lazy.

The Astrodienst text mentions a method by Hipparchus, stating that 0? Aries rose when Spica sets (on the island of Rhodos). the result is close to Zeta Piscium, the star of Revati of the Indian astrologers. So it seems that the Greeks (although vaguely) did use a fiducial star.

Thats a very dramatic claim.

Is this a method used to calculate the zodiac though? I would want to see a lot of evidence to support that suggestion. Where are they sourcing this from Hipparchus? Hardly any of his writings have been passed down to us. Is this something refered to by Ptolemy in the Almagest? Moreover, is there any evidence other hellenistic astrologers were influenced by this? This doesn't really seem to readily tally with the research of Otto Neugebauer and H.B. Van Hoessen in Greek Horoscopes. Those horoscopes do not seem aligned to the fixed stars you suggest. Can you see any way how Zeta Piscium could have been placed at 8 or 10 Aries following a sidereal zodiac? It seems odd and frankly most unlikely no Greek or Roman astrologer thought to mention this if it was the case. Greek and Roman astrologers seem to have happily continued to used 8 or 10 Aries to the end of the classical era. Indeed there are some examples into the medieval era.

Hipparchus was fundamentally an astronomer. He made no comment of an astrological nature as far as I am aware. Hipparchus used many astronomical techniques that had no direct astrological application. For example, he seems to have primarily used an equitorial system to plot the position of stars and planets rather than the ecliptic. So it doesn't follow that this has any diirect relevance to this topic.

We have sadly no surviving copy of his Star Catalogue which Ptolemy used. Just about the only substantial text left by Hipparchus is his Commentary on Aratus and Eudoxus. I admit that would be a fascinating text to read and might shed some light on this issue. Unfortunately, there is no translation in English yet. I will check my copy of Gemino's Introduction to the Phenomena to see what he says on this point.

It appears so and it seems that that Hipparchus point / or the Revati star was used as 'zero'. Most nakshatras then 'fit' but Purva Bhadrapada and Uttara Bhadrapada are quite off. However note that like the original 12 signs the 27/28 nakshatras originally were of different length.

I remain unconvinced about your 'Hipparchus point' but your suggestions on the Nakshastras are very interesting. My theory is that the origin of Indian sidereal astrology is an indigenous development rather than an importation from hellenistic astrology.

I was thinking of the Rochberg article on rulerships we discussed in the other sidereal thread. In the 7th century BC the signs were not only of unequal size but the (12 familiar) signs had boundaries with left 'empty' spaces in between. I don't know what thes would have meant during this 'transition' period.

An interesting observation. Hopefully, we can pick that point up when Gavin White's article on the exaltations appears.

MarkC wrote:Fagan, and Allen with final refinements by Bradley calculated Spica to be around 29 06' Virgo rather than at 00 Libra as in the Lahiri zodiac. This restores Spica to its ancient role as the alpha star of Virgo. This left Aldebaran at 15.00 Taurus. Of course the Pleiades run over several degrees. There is approximately 10 degrees between the alpha star Alycone and Aldebaran. The Vernal point of the Fagan-Allen-Bradley zodiac is at 05 Pisces.

Their zodiac is also mentioned in the paragraphs of Astrodienst. They also conclude with the Lahiri ayanamsha with the remark that if the Babylonians had used Spica as 180? this would be too clear to get forgotten through the times.

By the way I found a method to get rid of all those disturbint things in that article. I copied it to a Word document on the computer then with "Edit" and then "Replace" you can type in all those pieces of text with the "<....> 'es" and replace them by nothing. As these pieces are almost all the same you get rid of them very soon. There are just a couple of different ones. It's a 10-15 minutes work and makes the text much more pleasant to read.

I have no such excuse. I was just being lazy.

I can be quite lazy myself. When I thought I had discovered something, it turned out that I had been stating the obvious when I read Pingree's article on trepidation more attentively. I should better read the links myself when I refer to them .

Is this a method used to calculate the zodiac though? I would want to see a lot of evidence to support that suggestion. Where are they sourcing this from Hipparchus? Hardly any of his writings have been passed down to us. Is this something refered to by Ptolemy in the Almagest? Moreover, is there any evidence other hellenistic astrologers were influenced by this? This doesn't really seem to readily tally with the research of Otto Neugebauer and H.B. Van Hoessen in Greek Horoscopes. Those horoscopes do not seem aligned to the fixed stars you suggest.

I agree it is a strange method and depends entirely on the position on the horizon in that era on the latitude of Rhodos. I don't feel attracted to it myself. They have the information from Raymond Mercier. I searched a bit on the internet and found this. http://74.125.77.132/search?q=cache:re6 ... clnk&gl=nl I didn't read it myself but a quick look shows that Astrodienst mentions the same essential parts.
They say that it links Hipparchus with the Indians, Arabs and Medieval astrologers and mention that the tables of Toledo, Al Kwarazmi, the Surya Siddhanta are based upon that point near Zeta Piscium.

Whether they are truely based upon Hipparchus or not I find these theories on the later historical development quite convincing, however it doesn't tempt me to convert to the sidereal reference frame.

The Astrodienst text mentions a method by Hipparchus, stating that 0? Aries rose when Spica sets (on the island of Rhodos). the result is close to Zeta Piscium, the star of Revati of the Indian astrologers. So it seems that the Greeks (although vaguely) did use a fiducial star.

Hello Eddy,

I have read Raymond Mercier's article and I think a careful reading of the article shows Mercier is not denying that Hipparchus worked from the framework of the equinoctual point when referencing the co-ordinates of the ecliptic.

As Raymond Mercier states:

''Hipparchus is measuring his distances on the ecliptic from the equinoctual point'.

However, this hasn't prevented some over enthusiastic siderealists misinterpreting Mercier's research and presenting it as vindication that Hipparchus used a fixed star to define the zero point of his zodiac. I took the following interpretation of Mercier's ideas from this siderealist website:

http://www.cycle-of-time.net/firstpointofaries.htm

The Hipparchan tradition

Raymond Mercier has shown that all of the ancient Greek and the medieval Arabic astronomical works located the zero point of the ecliptic somewhere between 10 and 22 arc minutes east of the star Zeta Piscium. This definition goes back to the great Greek astronomer Hipparchus. How did he choose that point? Hipparchus said that the beginning of Aries rises when Spica sets. This statement was meant for a geographical latitude of 36?, the latitude of the island of Rhodos, which Hipparchus? descriptions of rises and settings are referred to.

(According to Mercier?s calculations, the Hipparchan zero point should have been between 12 and 22 arc min east of zeta Piscium, but the Hipparchan ayanamsha, as given by Mercier, has actually the zero point 26? east of zeta Piscium. This comes from the fact that Mercier refers to the Hipparchan position of zeta Piscium, which was at least rounded to 10? ? if otherwise correct.)

If we used the explicit statement of Hipparchus that Aries rose when Spica set at a geographical latitude of 36 degrees, the precise ayanamsha would be -8?58?13? for 27 June ?128 (jd 1674484) and zePsc would be found at 29pi12?, which is too far from the place where it ought to be.

I believe I understand what Hipparchus was actually describing here and I do not think it was in any way related to a zodiacal fiducial star. I am basing that on some recent research on Hipparchus I have been looking at. In that respect I believe Mercier's research has little actual relevance to astrology even if it has astronomical significance.

I fully understand why siderealists have seized on this as proof of a Hellenistic sidereal zodiac. Its certainly an amusing and ironic twist to be suggesting the discoverer of precession used a fixed star to mark the beginning of the zodiac.

However, I think there is a fundamental misunderstanding going on here regarding what Hipparchus was actually describing.

Unfortunately, I do not have the time to post up my explanation and cite references just now as I going to be away from the forum for a while due to other demands. However, I hope to return to this topic next week.

Incidentally, here is an article proposing that Lamda Scorpii (Mula Nakshastra) was the original fiducial star of both the Babylonian and Indian traditions.

http://www.new.dli.ernet.in/rawdatauplo ... 60_257.pdf