The Extraction of Determinations for Lunar Days

...the traditionalists original: "sāṃpradāyikāḥ" say it is worshipful. This fourth lunar day referring to the fourth day of the bright fortnight should pervade the midday; if it is not present at midday, but lasts for at least one Muhurta Muhurta: a unit of time equal to 48 minutes, the later day is chosen. The Naga-chaturthi a festival dedicated to snake worship should be observed as a fast only when it pervades the midday. If both days are pervaded by it, or if neither are, the later day is preferred. Regarding the eighth lunar day and snake worship, if the tithi Tithi: a lunar day lasts for three Muhurtas, the later day is chosen; otherwise, the former day should be taken. The same rule applies to the fifth lunar days of the months of Ashadha, Kartika, and Margashirsha. For the fourteenth day of the bright fortnight of Shravana, during rituals like the Kukkuta-dharma and the Pavitrarpana offerings of sacred threads to a deity, the former day only should be selected. Madhava Madhavacharya, a 14th-century authority on ritual law states that the day pervading the evening should be accepted. This specialty is similar to the rules for the fourteenth day of the bright fortnight of the month of Chaitra. On this very day, one should perform the Upakarma Upakarma: a Vedic ritual involving the renewal of the sacred thread worn by the twice-born castes during the Shravana constellation Nakshatra. If the constellation occurs on both days...

...when there is a constellation conjunction, Shravana the 22nd lunar mansion joined with Dhanishta the 23rd lunar mansion should be accepted. That which is joined with Uttarashadha the 21st lunar mansion is forbidden. If on the first day there is a conjunction with Uttarashadha and on the following day there is an absence of Shravana, or if it lasts less than two Ghatikas Ghatika: a traditional unit of time equal to 24 minutes, then the ritual should be performed on the fifth day when it is joined with the Hasta constellation. Similarly, the ritual should not be performed during a Samkranti Samkranti: the transit of the sun from one zodiac sign to another, an eclipse, the setting of Jupiter or Venus referring to when these planets are too close to the sun to be visible, which is considered inauspicious, or during an intercalary month an extra "leap" month in the Hindu calendar. Alternatively, during an eclipse, transit, or the setting of Jupiter and Venus, only new students those performing the ritual for the first time should perform it on the fifth day; for others, it remains on that Shravana day itself. Even in those cases, after midnight, the daily ritual should be performed only when joined with the Shravana constellation. The ancient followers of the Taittiriya school a specific lineage and branch of the Black Yajur Veda should perform it on the Full Moon day Purnima that pervades the sunrise. For the Katyayanas followers of the Katyayana school of the White Yajur Veda, however, on both days...