In attempting a summary of this discussion:
Rumen Kolev and disciples of the Fagan-Bradley sidereal school use Babylonian texts and the work of early 20th century scholars (Kugler and Huber) as evidence to place Antares and Aldebaran at precisely 15 degrees of Scorpio and Taurus in what is known as the "Babylonian fixed zodiac."
However, later scholars do not find this research convincing. Under "Norming of the Zodiac" (p. 131-133) in The Heavenly Writing (2004) Francesca Rochberg writes:
"Also the longitudes of the fixed stars were done so arbitrarily with the result that the zero degree of the ecliptic did not coincide with the vernal equinox...More precisely however, we still cannot establish the star that originally served as norming point for the ecliptic. Even were we to assume the vernal point was determined correctly when it was assigned to 10 degrees and then 8 degrees Aries, the corresponding dates for these zodiacal norming points cannot be pinpointed..." (p. 133) (Relevant references are noted in footnotes.)
Today's astrologers are likely to see this disagreement as "a tempest in a teapot" as Mr. Meyers stated. Astrologers are also likely to agree with Mr. Meyers' statement: "With a standard deviation of 3 degrees concerning the positions used to assess precession factors, discussing the correctness of two such factors with a difference of 1 degree between them seems to me a simple absurdity."
What matters to astrologers is the practical application of an ayanamsa: finding a way to demonstrate the exact beginnings and endings of zodiacal signs, most easily through the use of micro-zodiacs (navamsa, dwad, etc.) Not being research or statistically minded, such proof by astrologers is likely far in the future.
At any rate, the norming of the zodiac using one or more fixed stars, while a legacy from the past valuable for historical research, is less relevant today. As an astronomer friend wrote to me recently: "The equinox, (moving or fixed to a conventional date such as 2000) is still the zero longitude point common to equatorial and ecliptic systems, but is no longer considered the primary definition. Rather, the astronomers track the equatorial pole and the ecliptic pole in terms of a stationary coordinate system fixed to very distant quasars." Astronomy marches on in the 21st century!
As Mr. Meyers also pointed out, stars have proper motion, though it can take centuries for this motion to affect ecliptic longitude in a way that would matter to astrologers.
Scholars and students will continue in their arguments and demonstrations attempting to find support for their convictions. For the time being, sidereal astrologers will continue the use of their favorite zodiac based likewise on personal conviction.
Footnote: I did find Rumen Kolev's research in support of the Babylonian astrolabe dated to 5,500 BC interesting and convincing. http://cura.free.fr/09-10/912rumen.html http://www.babylonianastrology.com/inde ... &Itemid=33