ἀρκτικὸς κύκλος

Παράλληλοι μὲν οἱ τοὺς αὐτοὺς πόλους ἔχοντες τῷ κόσμῳ. Εἰσί δὲ παράλληλοι κύκλοι εʹ· ἀρκτικός, θερινὸς τροπικός, ἰσημερινός, χειμερινὸς τροπικός, ἀνταρκτικός.

‘Parallel are those that have the same poles as the cosmos. There are 5 parallel circles: the arctic circle, the summer tropic, the celestial equator, the winter tropic, the antarctic circle.’

Ἀρκτικὸς μὲν οὖν ἐστι κύκλος ὁ μέγιστος τῶν ἀεὶ θεωρουμένων κύκλων, ὁ ἐφαπτόμενος τοῦ ὁρίζοντος καθ’ ἓν σημεῖον καὶ ὅλος ὑπὲρ γῆν ἀπολαμβανόμενος, ἐν ᾧ τὰ κείμενα τῶν ἄστρων οὔτε δύσιν οὔτε ἀνατολὴν ποιεῖται, ἀλλὰ δι’ ὅλης τῆς νυκτὸς περὶ τὸν πόλον στρεφόμενα θεωρεῖται. Οὗτος δὲ ὁ κύκλος ἐν τῇ καθ’ ἡμᾶς οἰκουμένῃ ὑπὸ τοῦ ἐμπροσθίου ποδὸς τῆς Μεγάλης Ἄρκτου περιγράφεται.

‘The arctic circle is the biggest of the always visible circles, the one touching the horizon in one point and as a whole taken aside above the earth, in which the stars lying in it never perform a setting nor a rising, but are observed during the whole night turning around the pole. This circle is delineated in the inhabited region among us by the front foot of the Great Bear.’