Human

1. One human month is one day and one night for Pitrs. The dark half is said to be the day and the bright half the night (of Pitrs). 
2. The human year is said to be one day of Devas. The Northern transit is the day and the Southern transit is the night (of Devas). 
3. The year of the Devas is considered to be a day of the Seven Sages (Ursa Major). 
4. A year of the Seven Sages is said to be one day of Dhruva.

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