To describe the dancing movements of these gods, their juxtapositions and the back circlings and advances of their circular courses on themselves; to tell which of the gods come into line with one another at their conjunctions and how many of them are in opposition, and in what order and at which times they pass in front of or behind one another, so that some are occluded from our view to reappear once again, thereby bringing terrors and portents of things to come to those who cannot reason to tell all this without the use of visible models would be labor spent in vain.