Fascinating thread, thanks for posting.
Graham Hancock has been delving into this type of archaeoastronomy for years. You might find some leads there (amongst some pretty interesting, though wild speculation, it must be admitted).
Another point in regard to your discussion of the anti-Hellenistic Essenes, and the inclusion in Enoch of astronomical theories attributed to the Greeks...
There are two frequent and very easily made errors in textual analyses of ancient manuscripts.
1. The confusion of the earliest known example of a manuscript or concept with the earliest possible example. In fact, the earliest known is the latest possible example, as earlier examples may have been (and quite likely, actually have been) lost to us, as that is how it usually goes with old things.
2. The idea that if manuscript A and manuscript B describe similar events, and A was produced prior to B, then B is therefore derived from A, and any differences are due to a corruption of A by B. This is an unfounded presumption against the possiblity of lost manuscripts C, D, E, etc., which might have been the sources for both A and B. Bad textual alanyses frequently ignore the possibility of literary missing links. Once such presumptions are disallowed, we see that questions as to the relative corruption of A and/or B from the original source remain unanswered.