Question

we calculate the time according to the position of which celestial body

Answer 1

we calculate time according to sun , it was followed by old people

Answer 2

If we wish to use a celestial body’s position in the celestial sphere to help us to navigate on the Earth’s surface, we must be able to translate that body’s celestial co-ordinate position into a geographical position expressed in terms of our earthbound geographical co-ordinate system.