Book 20
3.4
In short, the sun is hidden and his brightness suppressed, when he himself and the orb of the moon, the lowest of all the heavenly bodies, accompanying each other and each keeping its proper course, maintaining the relation of height between them and being in conjunction, as Ptolemy wisely and elegantly expresses it μαθνηατικὴ σύνταξις, vi. 6. have come to the points which in Greek we call ἀναβιβάζοντας and καταβιβάζοντας ἐκλειπτικοὶ σύνδεσμοι Ascending and descending ecliptic nodes. The moon in its course shifts from one side to the other of the ecliptic, or sun’s course (see § 2, above). The nodes are the points where the moon passes the ecliptic; the node where she passes from the south to the north side is called ascending, that where she changes from north to south, descending. (that is, eclipse nodes). And if they merely graze the spaces adjacent to these nodes, the eclipse will be partial.
3.5
If, on the other hand, they stand in the nodes themselves which closely unite the ascent and the descent, the heaven will be overcast with thicker darkness, so that because of the density of the air we cannot see even objects which are near and close at hand.
3.6
Now it is thought that two suns are seen, if a cloud, raised higher than common and shining brightly from its nearness to the eternal fires,I.e. the sun. reflects a second brilliant orb, as if from a very clear mirror.
