4. The preceding exercise did not involve glyph number 266, which I have proposed to be day zero for the antipodal stars:

141 9
Gb2-10 (#0) Gb6-25 Gb6-26 Gb7-8 Gb7-9 (#154)
142 10 Achird (11.7)
154

Although the design of mago in Gb2-10 suggests this is where summer turns into winter and although it is glyph number 266 (counted from Gb8-30) it evidently does not stand at autumn equinox in the text of G (given that we have located winter solstice correctly at Ga1-27--28):

58
Ga8-1 (205) Ga8-2 (*270) Ga8-3
summer solstice Gb2-10 (*330)
27
Gb3-1 Gb3-2 (295) Gb3-3 (*360)
autumn equinox

Its position is about a month (28 days) earlier. Therefore its location north of the equator should be about a month before spring equinox:

South of the equator North of the equator
autumn equinox 266 spring equinox 80 (89)
Achird 266 + 11.7 = 277.7 Achird 89 + 11.7 = 100.7
winter solstice 358 = 266 +172 - 80 summer solstice 172 (181)
Sun returns (Naos) 23 (*122) = 87 - 64 Sun leaves (Naos) 202 (211)
Achir (Regulus) 266 + 153.7 - 358 = 61.7 Achir (Regulus) 89 + 153.7 = 242.7
spring equinox 87 = 358 + (266 - 172) - 365 autumn equinox 266 (275)
summer solstice 177 = 87 + (356 - 266) winter solstice 356 (365)
Sun leaves (Altair) 202 (*301) = 23 + 179 Sun returns (Altair) 16 (25)
Gb2-10 238 (*330) = 177 + 61 Gb2-10 417 (52)

*330 = 266 + 64, i.e. the number of days from spring equinox north of the equator. South of the equator day number 238 is equal to 177 + 61 (the number of days from summer solstice). Glyph number 266 represents day number *330 (= 266 + 64) from autumn equinox and also day number 330 - 92 = 238 from winter solstice (where 92 is the number of days from autumn equinox to winter sosltice). Thus we can translate the glyph number for Gb2-10, 266, to days from winter solstice by reducing with 28 (= 92 - 64), i.e. Gb2-10 represents day number 266 - 28 = 238 after winter solstice. It is day number 61 after summer solstice because 238 - 177 = 61.

North of the equator 417 = 365 + 52, where 52 = 61 - 9 (the number of days from winter solstice to January 1).

Glyph number 238 (= 177 + 61) corresponds to a complex glyph appearing just after 8 lunar months (8 * 29½ = 236 days from Gb8-30):

Gb1-5 Gb1-6 (*300) Gb1-7 Gb1-8 (238) Gb1-9

The corresponding time north of the equator could be at glyph number 365 + 61 = 426 if we continue for more than a year. But if we count time from January 1 the number will be 9 less (with 52 instead of 61) - because winter solstice comes 9 days before January 1 - and the corresponding glyph will be Gb7-6:

Gb7-5 Gb7-6 (417) Gb7-7 Gb7-8 Gb7-9

Raaraa in Gb7-6 is the same type of sign as in the central position of Gb1-8. It probably means we are on the right track.

We can use 28 (= 92 - 64) to 'translate' glyph numbers to day numbers according to right ascension but counted from winter solstice:

58
Ga8-1 (205) Ga8-2 (*270) Ga8-3
summer solstice     Gb2-10 (*330)
205 + 64 - 92 = 177 61

By assuming winter solstice to be at Ga1-27--28 it necessarily implies we have to reduce the glyph numbers with 28 to find the day numbers counted from winter solstice.

And then we can change the perspective to that north of the equator, where 90 days from Gb2-10 - this time presumably at autumn equinox - we could arrive at winter solstice:

6
Gb4-33 (354) Gb5-1 Gb5-2 (*420) Gb5-3 Gb5-4   Gb5-11 (365)
    December 21 9
49
Gb5-12 (*430) Gb5-13 Gb7-6 (417)
52

Winter solstice north of the equator does not always arrive on December 21 (day number 356), sometimes it comes on December 20 (as for instance in the year 2001). We should therefore think of Gb5-1--2 as the place for the winter solstice according to our own calendar. This is 90 days beyond mago in Gb2-10:

86 9
Gb2-10 (#0) Gb2-11 Gb4-33 (354) Gb5-1 Gb5-2 (#90) Gb5-12 (366)
September 22 23 19 20 December 21 January 1

Autumn equinox north of the equator sometimes (e.g. in 2011) comes on September 23.

We have evidently succeeded in coordinating our own calendar with that on the G tablet. 354 = 12 * 29½ and then follow 12 days to January 1.

Gb5-2 could be said to be at day number 420 (= 356 + 64) counted from spring equinox north of the equator = autumn equinox on Easter Island. 356 - 28 = 328 (= 420 - 92) could be its day number counted from winter solstice (on Easter Island). There are 355 - 294 = 61 days from autumn equinox. Winter solstice should be at glyph number **266 + 92 = **386:

58
Ga8-1 (205) Ga8-2 (*270) Ga8-3
summer solstice Gb2-10 (*330)
27
Gb3-1 (**266) Gb3-2 (295) Gb3-3 (*360)
autumn equinox
57 9
Gb4-33 (354) Gb5-1 Gb5-2 (#90) Gb5-12 (366)
19 20 December 21 January 1
17
Gb6-1 (384) Gb6-2 Gb6-3 (#120) Gb6-4 Gb6-5 (**360) Gb6-6
19 20 21 22 23 24
    winter solstice

Autumn equinox comes 28 days beyond glyph number 266 and **266 at takaure in Gb3-1 means we have added 64 and subtracted 92 from the glyph number (294).