jwposter:
If you chose the date of April 23 on -511 as the first of the month you would be wrong because it is NOT the first crescent.
I didn't choose the date. The date is dictated by the date of the solstice. Your alternative chronology is simply wrong.
You do realize that in -567, that the solstice would be even farther away from a true solstice than that reported in -511 don't you? So based on your argument you can't be supporting -567 since that would be farther away from the true solstice.
It is indeed becoming very evident that you do not know how to use an astronomy program.