Jayapatākā Swami: Uttarāyaṇa was the second consideration, but the actual fact was that Kṛṣṇa was present. So he wanted to leave with full concentration on Kṛṣṇa. But we observe the Bhīṣma Pancaka at the time it is prescribed. The śāstra say that at the end of Kārtika month, from Ekādaśī to Pūrṇimā. Why it is done at this time, I do not know, but this is mentioned in the Hari-bhakti Vilāsa and also in other scriptures in this way.
25-07-2021 Śrīdhām Māyāpur, India