John Buzzard: The Babylonian Ayanamsa
The zodiac as used by the Babylonians was sidereal. This makes one curious about the startingpoint of their zodiac. What 'Ayanamsa' did the Babylonian astrologers use?
Well, actually the term Ayanamsa is Vedic and not used by the Babylonians. But they did calculate positions relative to the fixed stars. And we do know about several cuneiform inscriptions mentioning the date of a planet entering a sign.
This makes it possible to calculate the starting point of the Babylonian zodiac.
Image: cuneiform tablet with babylonian planetary positions.
The work of Peter Huber
Peter Huber [1] made a thorough study of this subject. Huber studied the positions in ancient Babylonian horoscopes. He compared the positions in these horoscopes with modern calculations. The differences were noted and the mean value of these differences was calculated.
Results
This resulted in a value of 4 degrees and 28 minutes for the year 99 BC [2]. However, most of the positions mentioned in cuneiform tablets, were rounded. So a margin for possible errors needs to be taken into account.
Huber calculated this error to be a maximum of 20 minutes of arc.
The calculations of Huber lead to an Ayanamsa of 23°27' in 1900 and 24°51' in 2000.
Compared with Fagan
The difference with the Ayanamsa as proposed by Cyril Fagan [3] and Bradley is very small: only 6 minutes of arc. Several authors claim this difference to be only 1 minute of arc. It seems they misinterpreted the text of Huber. The original document says:
Berücksichtigen wir diejenigen Sterne, deren Längen sich eindwandfrei aus den Almanachen und NS-Almanachen ergaben [...], so erhalten wir eine mittlere Nullpunktkorrektur [....] für -100 von 4°22'.[....] Ziehen wir schliesslich alle Sterne heran, deren babylonische Länge wir kennen [...] . so ergibt sich für mittlere Nullpunktkorrektur
4°28' ± 20'
The bold emphisization is by Peter Huber.
The translation of this text:
If we take into account those stars of which the longitude can be convincingly determined from the Almanacs and the NS-Almanacs [...], then we'll get a mean Zeropoint correction [...] for -100 of 4°22'.[....] If we eventually include all Stars of which we now the Babylonmian longitude [...], then we'll get a value for the mean Zeropoint correction of
4°28' ± 20'
The value of 4°28' is the one we use.
OK, the values of Huber and Fagan are still close but it's not as striking as some publications want you to believe.
Conclusion
If you want to use a sidereal zodiac you need to choose an Ayanamsa. The calculations of Peter Huber give you a good Ayanamsa to start experimenting with.
Online calculation
You can make an online calculation using the Ayanamsa of Peter Huber. Or using another Ayanamsa's. Check out RadixPro's free online calculation.
Notes
- [1] Peter Huber, Ueber den Nullpunkt der babylonischen Ekliptik. Centaurus, 1958: vol.5: pp.192-208. [back]
- [2] Huber uses the year -100. This is the astronomical notation. Historically this is the year 99 BC. The difference is caused by not using a year zero in historical notation. [back]
- [3] Cyril Fagan and Brigadier R.C. Firebrace. Primer of Sidereal Astrology. Isabella, Mo., 1971 (Fourth edition) [back]
