Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
पूर्वद्वये परेद्युः स्यात्संगवात्परतो मनीषिभिः । सद्यः कालः परेद्युः स्याज्ज्ञेयमेवं तिथिक्षये ॥ ३९ ॥
pūrvadvaye paredyuḥ syātsaṃgavātparato manīṣibhiḥ | sadyaḥ kālaḥ paredyuḥ syājjñeyamevaṃ tithikṣaye || 39 ||
When a tithi is lost (tithi-kṣaya), the wise declare that in the first two time-divisions the rule of the “next day” (paredyuḥ) applies. But after the saṅgava period, the “same-day time” is to be understood as belonging to the “next day”—thus it is to be known when a tithi disappears.
Sanatkumara (teaching Narada)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: adbhuta
It safeguards dharma by ensuring vows and worship are performed at the correct sacred time; accurate kāla (time) is treated as an essential support for meritorious action.
Bhakti practices like vrata, pūjā, and upavāsa depend on proper tithi timing; the verse provides a rule so devotion is aligned with śāstric time-reckoning even during tithi-kṣaya.
Vedāṅga Jyotiṣa (astronomical calendrics): it gives a decision rule using saṅgava and day-divisions to assign ‘same-day time’ to the next day when a tithi is lost.