PAL

Ptolemaeus Arabus et Latinus

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τὸ τοῦ ὁρίζοντος ἐπίπεδον ‘the plane of the horizon’

Greek

References: Alm. Heiberg: I.12, 65:7-8
Translated into:
Arabic: بسيط الأفق [Alm. MS Tunis: ]
Arabic: سطح الأفق [Alm. MS Leiden: f. 10v]
Modern translations:
English: the plane of the horizon [Alm. Toomer: 62]