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When it changes from a new moon to a half moon, contrary to the above situation, the moon sets in the western sky at midnight, and such a half moon is called winding. The half month after the full moon is called the last quarter moon.

After the first quarter moon, the moon rises later and later, usually after midnight. At this time, in the east of dawn, a sickle-shaped crescent moon began to appear and stayed in the sky after dawn. This moon is called the waning moon. As soon as the waning moon passes, the moon will gradually "thin", and it is time to welcome the new moon.

After 29 days 12 hours and 44 minutes, the moon went round and round, from missing to round. Throughout the ages, people have always regarded this cycle as a month and called it the calendar block or the lunar calendar. The cycle of the moon's profit and loss is about two days longer than its time around the earth. This is because when the moon turns from the new moon and returns to its original position, the sun has left its original position and made a big step forward. That means it will take two days to catch up with the sun. If you don't catch up with the sun, you can't become a new moon.