Fifteen moons and sixteen circles are an astronomical phenomenon. The reason is that the standard of the lunar calendar is that the first day of the first day must fall on the moon. Usually, if it is the early morning of the first day of junior high school, then the fifteenth night should be hope. Therefore, when the new moon appears later this month, it is expected to appear on the 16th. Sometimes even to 17 years old. The most perfect and brightest moment of the moon is just around the corner. What is "hope"? On the first day of the lunar calendar, when the moon moves between the earth and the sun, the illuminated hemisphere of the moon faces away from the earth. We can't see the moon. It is called "new moon" or "new moon". On the fifteenth and sixteenth day of the lunar calendar, the bright side of the moon faces the earth, so we see a full moon, which is called "full moon" or "looking".

It also depends on the change of the phase of the moon. We know that the moon will not stop rotating around the earth, which is why the shape and size of the moon will change. This is the so-called moon phase transition.

Specifically, when the moon runs directly between the earth and the sun, it is called "new moon" in astronomy, and the moon can't be seen at night. The moon turns 90 degrees around the earth, which is called "around". When it is dark, half the moon is in the sky. When the moon turns 90 degrees again, it is called "looking". The moon and the sun are on both sides of the earth. When it is dark, we can see a bright moon rising in the east. At this time, the moon is the most round.

It is also understandable that on the first day of the lunar calendar, we can't see the moon, which is called "new moon" or "new moon". On the fifteenth day of the lunar calendar, we saw a full moon called "Full Moon" or "Hope".

Astronomically, it takes about 29.53 days for the moon to go around the earth and move from the "new moon" position to the next "new moon" position. It takes about 15 days for the moon to move from the new moon position to the observation position.

Astronomy stipulates that every "new moon" must be the first day of the lunar calendar, which makes the time of "looking" not fixed on the fifteenth day of the lunar calendar, but also on the sixteenth or even seventeenth day. So there will be fifteen moons, sixteen circles and even seventeen circles.