 Timekeeping as well as the nature of solar and lunar movements are mentioned in Vedic texts.For example, Kaushitaki Brahmana chapter 19.3 mentions the shift in the relative location of the sun towards north for 6 months, and south for 6 months.The ancient extant text on Jyotisha is the "Vedanga-Jyotisha", which exists in two editions, one linked to Rigveda and other to Yajurveda.