What did Zhang Heng invent the armillary sphere for?

From the beginning of each month, this instrument produces one konoha a day, and when May is full, * * * produces 15 konoha; From the date of 16, one piece of wood leaf will be transferred to the instrument every day, and all of them will be transferred to the instrument by the end of the month, so that the date and the moon's cycle can be known. ?

In this way, the elephant will automatically turn and turn. get through

Choose the right gear and number of teeth to make the elephant stay with the ground day and night.

The rotation speed of the ball is consistent to demonstrate the Sunday movement of the starry sky, such as

The appearance and transit of stars. By monitoring it, people can

Understand the changes of the sun, moon, stars and solar terms.