Robert, the zodiac as man is the simplest theory. The zodiac accords with Bible culture and is the principle of organization of Ecclesiastes. It's an object that anyone can see and its human association is traditional. It's the humane structure through which the sun moves. It is the human pattern in the sky -- a logos in the heavens.
There isn't any encoding -- if one considers the culture of the time. Cultural change conceals sources. Despite creationists, First Genesis is clearly based on astrological thinking:
Sun day: light created;
Moon day: waters separated;
and so on for the rest.
Thanks for the explanation of why Christmas occurs after the solstice.