Monday, 18 July 2016
The celestial north.
The easiest way to imagine the movement of the sky...
Is to use an umbrella.
The sky turns around a still point known as the pole.
The angle between the ground and the still point in the sky is your latitude.
So, the umbrella's handle is the pole.
The sky is rotating from right to left
So imagine twisting the umbrella so the right side comes up and the left side goes down.
A line 90 degrees to the umbrella handle, points to the highest part of the celestial equator in the southern sky.