How to describe the full moon and the lack of the moon?

The shape of the moon every day in a month is:

1, new moon (new moon, the first day of the lunar calendar): basically invisible, or vaguely see a thin line;

2, moth eyebrow month (the second day to the sixth day of the lunar calendar): if the eyebrows are like bows;

3. First quarter moon (seventh to eighth day of the lunar calendar): semicircle;

4. Gradual surplus and convex moon (the ninth to fourteenth day of the ninth lunar month): ellipse;

5. Full moon (full moon from 15th to 16th lunar month): disk surface;

6, gradually losing the convex moon (lunar calendar 17 ~ 23): ellipse;

7. First quarter moon (around the 23rd lunar month): semicircle;

8. The waning moon (from the 24th to the end of the lunar calendar): it looks like an eyebrow like a bow;

9. The last day of the lunar month turned into a new moon: basically invisible, or vaguely seeing a thin line.

Extended data:

In astronomy, the moon phase refers to the part of the moon that is illuminated by the sun as seen from the earth. The moon revolves around the earth, so the relative positions of the sun, the earth and the moon change regularly within a month. Because the moon itself is not luminous and opaque, the visible part of the moon is the part that reflects sunlight. Only the part of the moon that is directly illuminated by the sun can reflect sunlight.

We see the part of the moon that is directly illuminated by the sun from different angles, which is the source of the moon phase. The moon phase is not caused by the earth covering the sun (this is an eclipse), but because we can only see the part of the moon illuminated by the sun, and its shadow part is the dark side of the moon itself.

Lunar calendar and moon phases:

The lunar calendar in astronomy mainly refers to the calendar arranged according to the moon phase cycle. The moon revolves around the earth once (taking the sun as a reference, but actually the moon revolves for more than one week) as January, that is, based on the first month of the lunar calendar, a year is divided into twelve calendar months. In agrometeorology, the lunar calendar is commonly known as lunar calendar, lunar calendar, ancient calendar and old calendar, which refers to the traditional summer calendar in China.

Astronomically speaking, the summer calendar is actually a kind of lunar calendar, because the lunar calendar needs extra information such as leap months, solar terms and festivals than the traditional lunar calendar.

References:

(Baidu Encyclopedia: Moon Phase)