"Some Greek astronomers and astrologers knew of the precession, though they did not know exactly what it was or how to calculate it. Hipparchus appears to have discovered it among the Greeks and calculated it at 36" per year, which Ptolemy, the most famous Greek astrologer, adopted. The Hindus, in the Surya Siddhanta calculated the rate as 54", much closer to what is observed today as 50.3" per year.a While modem scholars consider this figure a lucky guess on the part of the Hindus it may reflect a better knowledge of the precession, perhaps arrived at by long term observations and necessary calendar shifts through time. For this reason, it is hard to derive Hindu astrology from the Greeks, as most Western scholars do. The Hindus compute the zodiac differently and the precession more accurately than the Greeks. Yet we are told, based upon the appearance of minor Greek terms in later Hindu astrology, that any accuracy in Hindu astronomy comes from the Greeks. Hindu astronomy has a long history and an extensive literature following different methods than those of the Greeks. As Vedic astrology is Sidereal, we cannot discountenance the astronomical references we find commonly in Vedic literature relative to the precession. Precessional changes are the hallmark of Hindu astronomy, the essence of the system. We cannot ignore them in ancient texts just because they give us dates too early for our conventional view of human history."