अथ च यावतार्धेन नभोवीथ्यां प्रचरति तं कालमयनमाचक्षते. ॥ ६ ॥
atha ca yavatardhena nabho-vithyam pracarati tam kalam ayanam acaksate.
atha-now; ca-also; yavata-by as long as; ardhena-half; nabhah-vithyam-in outer space; pracarati-the sun moves; tam-that; kalam-time; ayanam-ayana; acaksate-is said.
Thus the time the sun takes to rotate through half of outer space is called an ayana, or its period of movement [in the north or in the south].