8. Once again. Moving 181 days back from Ga1-27 we first can take a step which is 28 + 64 = 92 days long in order to reach March 21. Next step is 80 + 9 = 89 days in order to arrive at solstice and December 21:

85 63 27
Gb3-29 (320) Gb3-30 Gb4-1 Gb6-25 (408) Gb6-26 (*1) Ga1-27
December 22 23 24 March 21 22 June 21
89 92
181 (= 172 + 9)
January 31 31
February 28 59
March 21 80
31 90
April 30 120
May 31 151
June 21 172
30 181
July 31 212
August 31 243
September 22 265
30 273
Oktober 31 304
November 30 334
December 21 355
31 365
South of the equator North of the equator
autumn equinox 266 89 = 266 - 177 spring equinox 80 (89)
Achird 266 + 11.7 = 277.7 92 = 358 - 266 Achird 89 + 11.7 = 100.7
winter solstice 358 = 266 +172 - 80 summer solstice 172 (181)
Sun returns (Naos) 23 (*122) = 87 - 64 87 Sun leaves (Naos) 202 (211)
Alterf 52 Alterf 240 = 211 + 29
Achir (Regulus) 266 + 153.7 - 358 = 61.7 Achir (Regulus) 89 + 153.7 = 242.7
Alkes 75 = 266 + 167 - 358 Alkes 256 = 89 + 167
spring equinox (Denebola) 87 = 358 + (266 - 172) - 365 autumn equinox (Denebola) 266 (275)
summer solstice 177 = 87 + (356 - 266) 90 = 177 - 87 winter solstice 356 (365)
Sun leaves (Altair) 202 (*301) = 23 + 179   Sun returns (Altair) 16 (25)

This exercise reveals that I may have been a little careless with the details. Autumn equinox north of the equator is according to my table day number 266 (or 275 from winter solstice), but September 22 is normally day number 265 in the calendar. I once based the estimate 266 on the years 2001-2004 and all these 4 years autumn equinox was in day 266 counted from January 1. In the current year (2013) autumn equinox will be in September 22 while in 2011 it was in September 23. In 2012 an extra day in February adjusted the calendar.

If we then continue our walk back in time the next step should take us to autumn equinox (north of the equator):

88 85
Gb1-1 (230) Gb3-28 Gb3-29 (320) Gb3-30 Gb4-1 Gb6-25 (408)
September 23 (266) 21 December 22 (356) 23 24 March 21
90 89
179

And should we search for September 16 (spring equinox on Easter Island) it too seems to give reasonable results:

Ga8-16 Ga8-17 (**192) Ga8-18 Ga8-19 (222) Ga8-20
12 13 14 September 15 16
Ga8-21 Ga8-22 Ga8-23 Ga8-24 Ga8-25 (228) Ga8-26
17 18 19 20 September 21 22

But if we instead should move forward from winter solstice (Ga1-27) at June 21 we will arrive at Ga8-20 after 195 (= 223 - 28) days and 172 + 195 = 367 suggests we have reached to the beginning of January.