अधोलोकवर्णनम् (Adholoka-varṇana) — Description of the Lower Worlds and Cosmographic Measures
विषुवं तं विजानीयादेवमाहुर्महर्षयः
viṣuvaṃ taṃ vijānīyādevamāhurmaharṣayaḥ
Know that to be the Viṣuva (equinox); thus have the great seers declared.