Matsyapurana 124.58

124.58

etāstu vīthayas tisro madhyamo mārga ucyate
hastaścitrā tathā svātī hy ajavīthiriti smṛtā //

And when the sun passes on to the asterisms Puṣya, Aśleṣâ and Punarvasu, then He is said to be on the Airâvatîvîthî. These three Vithîs comprise the Uttaramârga (northern course). When the sun is in Pûrva and Uttaraphâlguṇa and Maghâ, the Vîthî is called Ârṣabhî. Purvâ and Uttarâprôṣṭhapada and Revati are the Govîthî; while Sravaṇa, Dhaniṣṭhâ and Vâruṇî are the Jaradgavavîthî. These three Vithîs form the middle course of the sun. Hastâ, Svâtî and Chitrâ are the Ajavîthî; Jyeṣṭhâ, Viśâkhâ and Maitra are the Mrigavîthî; Mûla, Pûrva and Uttara Âṣâḍha are the Vaiśvânaravîthî. These three Vithîs form the southern route of the sun; now the (chordal) distance between the extreme points of these (Vîthis), each should be noted.—40-60.