According to Ernst Wilhelm, (www.vedic-astrology.net) when asked about the Sri Yukteswar Ayanamsha:
“Sri Yuktesvar never used the ayanamsa named after him. When he wrote the Holy Science and talked about the Yugas he used Mean Motions of the precession, which is 24000 years, just like Manu Samhita uses the same mean motions. Talking in mean motions makes truth for all time. However, in this particular cycle, it will take 25600 years for the equinoxes to progress through the zodiac. And Sri Yuktesvar knew this of course as it was known during that time. He then goes on to say that the revati star marks the first point of sidereal aries, which is what the galactic center middle of mula ayanamsa comes to by the way. The then uses mean motions to arrive at a revati position that is not true from observation, but true from a mean motion point of view. Yuktesvar was not talking about precession in respect to
astrologers calculating an ayanamsa, but about mean motions of the great cycle. Readers did not understand this and so derived an ayanamsa based on mean motions in his book – not what he intended. But that is the norm, people take wise words and do the unintentional with them.
Additionally, Tara Ma, a disciple of Yogananda who was very much into occult sciences and who Yogananda said that if he wanted to talk of metaphysical things and could not talk to Yuktesvar, his favorite person to talk to was Tara Ma. Tara Ma derived an ayanamsa based on the true motion of this period’s precession, 25600 years, and the actual position of Revati and in so doing came up with an ayanamsa very close to dhruva galactic center middle of Mula.
One thing that has to be kept in mind is that no star marks the ayanamsa. Ancients just used stars as reference points, Yukteswar actually said 10 mintues from Revati. But now that we have discovered the galactic center we can use what is actually fixed, the galactic center. NO stars are really fixed, they all move, decay, burn out, etc. Only the GC, the galactic center, will be here through the entirety of our galaxy’s existence. But the dhruva galactic center middle of Mula ayanamsa is marked by Revati, the star chosen by Sri Yuktesvar.”