How to treat cloud and starry sky photography

Divide the sky into 10 equal parts, and the number of parts covered by clouds is the cloud amount.

Cloud cover is estimated. There is no cloud in the blue sky, the cloud amount is 0, the cloud covers the sky 6 times, and the cloud amount is 6. The number of high, medium and low clouds covering the same sky is called "total cloud cover".

Low cloud cover is called "low cloud cover". The distribution of cloud cover on the earth's surface is very uneven, with the maximum cloud cover near the equator in the whole year and the minimum cloud cover in the desert area of 20-30 north and south latitude.