2. Such a division of the year in 2 halves agrees with the idea of a pair of 'years', one 'in leaf' and the other 'in straw'. The precession is gradually changing the right ascension values for the stars, but the basic structure with 2 halves does not change:

"First point (or cusp) of Aries and first point of Libra are names used by navigators and astrologers. Navigational ephemeris tables record the geographic position of the First Point of Aries as the reference for position of navigational stars. Due to the precession of the equinoxes, the astrological signs of the tropical zodiac where these equinoxes are located no longer correspond with the actual constellations once ascribed to them. The equinoxes are currently in the constellations of Pisces and Virgo. In sidereal astrology (notably Hindu astrology), by contrast, the first point of Aries remains aligned with Ras Hammel 'the head of the ram', i.e. the Aries constellation." (Wikipedia)

Neither Hamal (the brightest star in Aries) nor any of the main stars of Libra are among the Tahitian star pillars, because precession has moved them away from the equinoxes.

In the Babylonian zodiac we can see that Libra is just an addition to the great Scropion sign.

250 days from autumn equinox Ana-mua is standing on the threshold to summer:

266 (autumn equinox) + 250 (Antares) = 516 days beyond winter solstice (south of the equator) = 516 - 365 = day number 151 counted from winter solstice.

Beyond Ana-mua lies summer, the 'year in leaf'. Sun is also a star, although a mighty powerful one, and the star list could therefore continue with Sun beyond Antares. He will rule the whole summer and then a new cycle can begin again from Polaris at the northern pole.