Tithi-Nirṇaya for Vratas: Ekādaśī Rules, Saṅkrānti Punya-kāla, Eclipse Observances, and Prāyaścitta
अर्केऽह्नि पर्वरारौ च चतुर्दश्यष्टमी दिवा । एकादश्यामहोरात्रं भुक्त्वा चांद्रायणं चरेत् ॥ ५६ ॥
arke'hni parvarārau ca caturdaśyaṣṭamī divā | ekādaśyāmahorātraṃ bhuktvā cāṃdrāyaṇaṃ caret || 56 ||
যদি রবিবারে, পর্ব-রাত্রিতে, চতুর্দশী বা অষ্টমীর দিনে, কিংবা একাদশীর দিন-রাত ভোজন করে ফেলে—তবে চন্দ্রায়ণ প্রায়শ্চিত্ত পালন করা উচিত।
Nārada (teaching in a dharma/vrata context, traditionally within Nārada–Sanatkumāra dialogue)
Vrata: Cāndrāyaṇa
Primary Rasa: bhayanaka
Secondary Rasa: shanta
It emphasizes tithi-based discipline: violating sacred fasting times (especially Ekādaśī and parva junctions) is treated as a dharmic lapse, remedied through the purifying Cāndrāyaṇa observance.
By safeguarding Ekādaśī and other sacred lunar timings, the verse supports steadiness in vrata and self-restraint—foundational supports for Viṣṇu-bhakti practice even when it is framed here as corrective penance.
It relies on calendrical computation of tithi and parva (a Jyotiṣa/Vedāṅga application): identifying Ekādaśī, aṣṭamī, caturdaśī, and parva-nights to determine proper ritual conduct and expiation.