How should I put the sundial?

The coffin should be placed north, like a globe. The pointer points to the north pole.

The surface of the sundial should be placed north, and the pointer of the sundial points to the North Pole. The direction of the sundial should be determined according to the latitude. When using the sundial, the angle between the hour hand and the ground plane must be consistent with the local geographical latitude at any time. As long as the tilt angle of the pointer is properly adjusted and parallel to the earth's rotation axis, the sundial can be used at different latitudes. A device that uses the shadow cast by the sun to determine the time is also called a heliograph.

principle of operation

The sundial literally means "the shadow of the sun", so its working principle is to specify the time according to the rotation direction and length of the shadow of the sun. On sunny days, the shadow of the sun will change constantly. As we all know, the shadow is the longest in the morning, and the length of the shadow becomes shorter as time goes by.

However, it is not intuitive and convenient to judge the time according to the length of the shadow, and the shadow will constantly shift according to the change of the day, and the position in the morning and evening is different, so the wise ancients thought it more convenient and accurate to specify the time according to the displacement of the shadow.