Srimad Bhagavatam — Saptama Skandha, Shloka 21
Gṛhastha-Dharma: How a Householder Attains Liberation by Offering All to Vāsudeva
अयने विषुवे कुर्याद् व्यतीपाते दिनक्षये । चन्द्रादित्योपरागे च द्वादश्यां श्रवणेषु च ॥ २० ॥ तृतीयायां शुक्लपक्षे नवम्यामथ कार्तिके । चतसृष्वप्यष्टकासु हेमन्ते शिशिरे तथा ॥ २१ ॥ माघे च सितसप्तम्यां मघाराकासमागमे । राकया चानुमत्या च मासर्क्षाणि युतान्यपि ॥ २२ ॥ द्वादश्यामनुराधा स्याच्छ्रवणस्तिस्र उत्तरा: । तिसृष्वेकादशी वासु जन्मर्क्षश्रोणयोगूयुक् ॥ २३ ॥
ayane viṣuve kuryād vyatīpāte dina-kṣaye candrādityoparāge ca dvādaśyāṁ śravaṇeṣu ca
应在摩羯与巨蟹转日（saṅkrānti）、白羊与天秤分点（viṣuva）、名为Vyatīpāta之瑜伽、日尽之时、三tithi并合之日、日月食之际、十二日（Dvādaśī）以及室罗伐那（Śravaṇa）宿之时，举行祭祖施食的śrāddha。
The word ayana means “path” or “going.” The six months when the sun moves toward the north are called uttarāyaṇa, or the northern path, and the six months when it moves south are called dakṣiṇāyana, or the southern path. These are mentioned in Bhagavad-gītā (8.24-25). The first day when the sun begins to move north and enter the zodiacal sign of Capricorn is called Makara-saṅkrānti, and the first day when the sun begins to move south and enter the sign of Cancer is called Karkaṭa-saṅkrānti. On these two days of the year, one should perform the śrāddha ceremony.
FAQs
In Canto 7, Chapter 14, Śukadeva lists particular tithis and seasons as especially suitable for performing prescribed sacred observances and duties for spiritual benefit.
He is instructing Parīkṣit on ideal household religious practice (gṛhastha-dharma), including when to perform time-honored observances that purify life and support devotion.
Choose a few key tithis (like Kārtika observances) for extra japa, charity, temple worship, and sāttvika living, using the calendar as a rhythm for consistent devotion.