Blue Moon Purnima 2026

Margashirsha (Agahan) is declared by Krishna in the Bhagavad Gita as his favourite month. The Purnima celebrates Dattatreya Jayanti — the birth of the three-in-one deity who combines the qualities of Brahma, Vishnu, and Mahesh.

Earth's shadow has two zones: the dark umbra and the lighter penumbra. At Purnima, the Moon passes outside both and is fully illuminated. The Hindu tithi system divides the lunar month into 30 tithis of roughly 24 hours each — Purnima is tithi 15 of the bright fortnight (Shukla Purnima). Because tithis are astronomically defined by the Moon's angular distance from the Sun, the IST peak time can fall morning, afternoon, or night depending on the year.