Melody formula of the first quarter moon

The new moon on the first day is invisible only because it is trapped in the sun and the earth.

On the eighth day of the seventh lunar month, the half moon faces west.

When the full moon comes out on the 15th and 16th, the earth shoulders the sun and the moon.

Twenty-two, three and the last quarter of the moon, the moon faces east until midnight.

The "crescent moon" between the new moon and the upper chord is called the new moon, and the "crescent moon" between the horizon and the lower chord is called the waning moon. A formula (easy to remember): up to the west, down to the east-meaning: in the first half of the month, the first quarter moon appeared in the west, in the west of the sky; The last quarter moon appears in the second half of the month. The moon faces east and lies in the eastern sky.

Extended data:

The source of the moon phase:

When the moon orbits the earth, the relative positions of the sun, the earth and the moon change regularly within one 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. 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 because the earth blocks the sun (this is an eclipse), but because only the part of the moon illuminated by the sun can be seen, and the shadow part is the dark side of the moon itself.

Baidu encyclopedia-moon phase

Baidu encyclopedia-first quarter moon