In Moreh Nevuchim (3:14) the Ranbam writes:
“Do not ask me to reconcile everything that they (i.e. Chazal) mentioned regarding astronomy with what is reality, for the sciences in those days were lacking, and they did not speak about them through traditions from the prophets, but rather on their own independent knowledge or what was obtained from contemporary scientists.”
The Rama in Toras HaOlah (1:2) quotes this Rambam and strongly disagrees, stating clearly that we assume rabbinic science to be infallible, and ancient rabbinic knowledge of astronomy complete. The Ramah has stated that we do not pasken like the Rambam here. As do the Maharal and the majority of our Torah authorities throughout the ages, as mentioned above.
Finally, if we take this statement of the Rambam in the context of his own statements elsewhere, what he says in More Nevuchim may mean something entirely different:
In summary:
3) The Rambam only stated that Chazal relied on the science of their times regarding astronomy, about with the Rambam himself states that we had a tradition from the prophets but it went lost, and that is why we must rely on the science of the gentiles.
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The Galgalim have sources in Chazal as well, as Rav Chaim Kanievsky points out in Kiryas Melech (Yesodei Hatorah 3:1).
Here’s how this works: The Rishonim will quote something from the Greek philosophers but which really comes from Kabbalah. They do this because when citing Kabalistic ideas, they often try to conceal them as much as possible. Therefore, if something is well known as a Greek philosophical concept, they will quote it as such even though its source is Judaism. Example: The Ramban’s hyly (hiuli?)at the beginning of Bereishis, which he notes and sources as Greek. Both the Satmar Rebbe (Divrei Yoel Bereishis p.61) and Rav Elya Lopian (quoted by Rav Scwardron) say the hyly is a Kabbalistic, spiritual idea, which the Greeks took from us. The Divrei Yoel explains that the Ramban quoted this in the name of the Greeks because it is the derech of the Ramban to camouphlage such sodos in physical terms – the same as Chazal often did. (see also Rama Toras HaOlah on Boruch Sheamar).
Another one of these concepts is the 4 elements (fire, waster, air, and earth), which is quoted all over by the Greeks but comes from Kabbalah – they took it from us.
The idea that the Greeks took their philosophical ideas from us is all over the Rishonim and Achronim, including the Ramban himself (Toras Hashem Temimah p.162). He says that they lifted their knowledge from the Jews, and eventually it got distorted by them. But the source is Judaism. The Kuzari says the same thing (2:66 – see also 2:19 and 1:62) as does the Shevili Emunah (nesiv 8) the Rama (he brings that Socrates got his wisdom from Asaf and Achitofel (Toras Haolah 1:12), and Chosid Yaavetz (Ohr Hachaim 6). The Chida (Midbar Kadmos – Sheva Chachmos) says this in the name of the Rambam (se also Moreh Nevuchim 1:71).
Basically what happened was, people like Shlomo HaMelech and the Neviim had this chachma, the Greek philosophers such as Plato and Aristotle learned from them, we went into Golus and a lot of it got lost, while among the Greeks it got grotesquely distorted. So youll find Torah and Kabbalistic concepts among the Goyim but kind of in a messed up way. Sometimes Rishonim such as the Ramban will identify some crumb of truth among them that comes from us and he will quote it from them if it is known as such.
Regarding Ptolmey himself, the Abarbanel (Shmos 12) quotes Ptolmey as being so impressed with the Jews’ astronomical calculations, that he said it proves the Jews had prophecy. In the Sefer Eretz Zvi (by Rav Aryeh Zvi Fromer ZTL, Rosh Yeshiva in Chachmei Lublin), quotes more such sources about Ptolmey.