Is the moon of the Lantern Festival a full moon?

The moon of Lantern Festival is full moon. The fifteenth day of the first month is usually the first full moon of the Lunar New Year. The new moon is called "new moon" in astronomy, which means that the moon and the sun are in the same direction, about 0 degrees apart. The full moon is called "king" in astronomy, which means that the angle between the moon and the sun is about 180 degrees. Strictly speaking, "new moon" and "hope" both refer to a certain moment. Because the orbital period of the moon's revolution is not very stable, the period of a "Shuowangyue" has been changing slightly.

The reason of the moon's circle and its change.

The orbit of the moon around the earth is an ellipse, which is near and far. The nearest one is more than 360 thousand kilometers, and the farthest one is more than 400 thousand kilometers. Because of gravity, the moon moves faster in the near future and slower in the long term. If you run fast in the first half of the month, the moon will reach the full moon position on the fourteenth or fifteenth day of the lunar calendar, showing a perfect circle in the night sky; If it moves slowly, the moon will reach the full moon position in the lunar calendar 16 or1July.