τούτου δὲ συμβαίνοντος ἀναγκαῖον γίγνεσθαι πάροδον καὶ τροπὰς τῶν ἐνδεδεμένων ἄστρων → but if this were so, there would have to be passings and turnings of the fixed stars
Use P. τὰ ὑπάρχοντα.
per se. Use P. αὐτὸς καθ' αὑτόν.