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 ||
من أكل يوم الأحد، أو في ليلة «پرفا» (ليلة اقتران القمر)، أو أكل نهارَ التشاتوردشي (اليوم الرابع عشر) أو الأشتَمي (اليوم الثامن)، أو أكل طوال نهار الإكادشي وليلِه—فعليه أن يلتزم بكفّارة «تشاندرايانا» (Cāndrāyaṇa) تطهيرًا للذنب.
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.