SB 1.9 - Bhīṣma's waiting for the right time to leave his body
Citing instances from history, Bhīṣma described dharma, artha, kāma and mokṣa along with the means to attain them. Incidents mentioned in the Purāṇas, Mahābhārata and Rāmāyaṇa are factual historical narrations and they happen on different universes. One should be simply concerned with the instructive lessons of such incidents and not their chronological order. Bhīṣma awaited the Uttarāyaṇa, the day when the sun enters the northern hemisphere. Uttarāyaṇa also means He who entered within Uttarā, who is Kṛṣṇa, who had entered the womb of Uttarā to protect Parīkṣit. While Bhīṣma was thus describing occupational duties, the sun’s course rain into the northern hemisphere (uttarāyaṇa), which is desired by mystics who die at their will. In Bhagavad gītā 8.24, it is said that those who leave the material body when the sun is in the northern horizon achieve the transcendental sky. The yogīs can leave their bodies at their will, and can go to any planet within a short time. Bhīṣma prepared to quit his body in the presence of the exalted Lord Śrī Kṛṣṇa, the pious Pāṇḍavas and the great sages.