The Kalpadi tithis
Classical astronomical and dharmashastra treatises, including the Matsya Purana, the Vishnu Dharmottara Purana, Hemadri's Chaturvarga Chintamani, and the Nirnaya Sindhu, enumerate the principal Kalpadi tithis across the lunar year.
Among the prominent Kalpadi dates are: Chaitra Shukla Tritiya (the start of the present creation and Matsya Jayanti), the Purnima of Vaishakha, Jyeshtha Shukla Dashami (celebrated as Ganga Dussehra), Ashadha Shukla Ekadashi (Devshayani Ekadashi), Shravana Shukla Dwadashi, Bhadrapada Shukla Tritiya (Hartalika Teej), Ashvina Shukla Navami (Maha Navami of Sharad Navratri), Kartika Shukla Dwadashi (Tulasi Vivah / Ksheerabdi Dwadashi), Margashirsha Shukla Trayodashi, Pausha Shukla Ekadashi (Putrada Ekadashi), Magha Shukla Saptami (Ratha Saptami / Arogya Saptami), and Phalguna Amavasya.
Cosmological significance of a Kalpa
A Kalpa represents the fundamental epochal unit of cosmic time in Vedic philosophy. Within each Kalpa of one thousand Mahayugas, fourteen successive Manvantaras arise and dissolve, overseen by distinct Manus, devas, and saptarishis. When Brahma's day closes, the universe enters a cosmic night of equal duration, known as Pralaya.
The current epoch is identified as the Shveta Varaha Kalpa, named after the divine incarnation of Lord Vishnu as the boar who lifted Mother Earth from the cosmic primeval ocean at creation's renewal.
Spiritual practices and Shraddha
Because a Kalpadi tithi holds the primal energy of universal origin, sacred acts undertaken on these days are declared by the scriptures to yield fruits that never decay (akshaya phala). Foremost among these observances is the performance of Pitru Shraddha or Tarpana using pure water, black sesame seeds (tila), and kusha grass, which is believed to bring profound peace and contentment to past ancestors.
Devotees also observe sacred snana in sanctified rivers like the Ganga and Yamuna, engage in silent meditation and Gayatri Japa, and donate food, clothing, and earthen lamps to deserving seekers.