... The system of Nakshatras, then, is quite distinct from systems that use the appearance of heliacally rising or setting stars as the equinoctial marker. Furthermore, the Indian system is all but unique in that two calendar systems competed with each other - a civil system, in which the year's beginning was at the winter solstice, and a sacrificial year, which begins at the spring equinox. The beginning of the former was determined by the Nakshatra method, observing the winter full moon's apparition near the point of the summer solstice in the sky ...

Rohini 9 (50)	10
Pleione 6 (20)	7
June 5	6 (157)
Cb3-1	Cb3-2 (443)
E vae ra - ka oho - ki te henua - kua huki	ku kikiu - te henua
5h (76.1)	λ Eridani (76.7)
Haedus II (75.9), ε Leporis (76.0), Cursa (76.4)
December 6 (340)	7
Az Zubana 8	9 (205)
Sabik (259.7), η Scorpii (259.9), Nodus I (260.0)	π Herculis (260.7), Ras Algethi (260.8), Sarin (261.0), ο Ophiuchi (261.4)

The 'gate of the goat' (Haedus I and II) could then be imagined as a 'door of exit' for the 'goat of winter' and the picture in Cb3-1 maybe should be interpreted from the nakshatra perspective.

The strong Spring Sun light would tend to make observations of the stars in the mornings (or evenings) difficult. The nakshatra method would be better. According to Worthen there is a minimum 16º distance between the last visibility of a star and the rising Sun:

... The heliacal rising of the Pleiades is the sign of the equinox. The Pleiades rose an hour before the sun and have become visible, since their separation from the sun [in 3102 B.C.] is just beyond the minimum distance of 16º that a star may be from the sun and still be visible ...

In rongorongo times the Pleiades began to rise heliacally in May 15 = 55 days after March 21. Around 3100 B.C. they rose an hour before the Sun, i. e. since that time precession has carried Sun ca 15 + 55 = 70 days earlier. (1870 + 3100) / 70 = 71 means Sun had moved with around 1 day each 71 years.

16º equals ca 16 days and March 21 (80) - 16 = 64 (March 5). Instead of the Pleiades cluster we should search for some star rising around March 5, a star which in rongorongo times could have been used to announce the equinox.

Reasonably this 'Sheratan' (dual of 'Sign') was the pair of 'Mouth Fishes' (Fom-al-haut and Fum al Samakah). Then there could have followed a 15-day long transition period ending with 32 Piscium: