First, to your question, as our sources don't explain the phenomena, the Sages knew about eclipses right after the other astronomers published their theories. BTW, the Sages didn't have weird ideas of various creatures as the Ptolemean school was widely accepted long ago (some 200 years before the Gm.).
Let me reveal the hoax of the most of #science tagged question about Judaism - "the Gemmorah represents the [pure] Jewish Oral tradition."
No, the Gm represents the opinions of the Chachamim that were full of external knowledge without properly admitting it. (I'm too tired to bring examples, but if you insist please comment). Therefore you can NEVER attribute any "scientific" saying found in the Gm to the Oral tradition.
Rambam says it in Hilchot Kidush Hachodesh, that all the divine knowledge the tribe of Issachar had as ומבני יששכר יודעי בינה לעתים (DhY A 12:33) was lost and all the astronomical knowledge the Sages had in the times of the Second Temple was external only. I didn't see anybody arguing that assertion.
Therefore whether the Sages discuss it or not, the discussion was not about the tradition, just like the dispute of R' Yehuda about Sun's trajectory at night (which the Sages unfortunately lost).
BTW, this is a funny claim "we had it but we lost it". What was the idea of giving the knowledge to lose it after 1000 years? And why didn't they take measures to keep it?