Moon phase changes in the first half of the month (please have pictures to clearly describe the moon phase changes on the first, third, fifth, seventh, ninth, eleventh, thirteenth and fifteenth day of

Moon phase changes in the first half of the month (please have pictures to clearly describe the moon phase changes on the first, third, fifth, seventh, ninth, eleventh, thirteenth and fifteenth day of the lunar month)

The moon is calculated based on the ecliptic longitude difference between the sun and the moon, and is divided into eight types (see below), of which the main four are new moon, first quarter moon, full moon, and last quarter moon.

1. New Moon (the first day of the lunar month is "Suo")

As shown at position A in Figure 1, the moon is near the ground and there is no reflection of sunlight, so the moon is basically invisible. The new moon is the moonrise in the morning and the moonset in the evening.

2. Emei Moon (the second to seventh day of the lunar calendar)

The moon orbits the earth and reaches position B as shown in Figure 1. The earth can see the illuminated part of the moon. , it is shaped like a sickle, facing the sun in the west. The Emei Moon rises after sunrise and sets after sunset. Therefore, the Emei Moon can only be seen in the western sky some time after sunset.

3. The first quarter moon (the eighth day of the lunar calendar is "Cheng")

As shown in position C in Figure 1, because the relative positions of the sun, the earth, and the moon are at a right angle of 90 degrees, At this time, the western half of the moon is observed to be bright. The first quarter moon rises at noon and appears in the southern sky at dusk. Assuming that the observer is located at mid-latitudes in the northern hemisphere, the moon can be observed to set on the western horizon at midnight. Visible in the first half of the night.

4. Waxing gibbous moon (from the ninth day of the lunar calendar to the fourteenth day of the lunar calendar)

At position D in Figure 1, at this time, most of the moon is facing the west and the gibbous moon will be at midday. It appears in the southeastern sky after dusk, sets on the western horizon before dawn, and is visible most of the night.

5. Full Moon (the fifteenth day of the lunar calendar means "looking", the sixteenth day of the lunar calendar means "looking")

Position E in Figure 1, when the sun and moon are on both sides of the earth , because there is an angle between the ecliptic plane and the ecliptic plane (about 5 degrees z on average), in most cases, the earth cannot block the sun's light, so the bright side of the moon is facing the earth, and people can see a bright moon. The Full Moon rises on the eastern horizon when the sun sets in the evening, is due south in the sky at midnight, and sets on the western horizon in the early morning. Visible all night long.

6. Waning Gibbous Moon (from the 17th to the 23rd of the lunar calendar)

At the position in F in Figure 1, most of the moon is facing east at this time. Due to the different relative positions, the waning gibbous moon "loses" a small part of the upper part, opposite the waxing gibbous moon. The waning gibbous moon rises after dusk and sets before noon, and is visible most of the night.

7. Last Quarter Moon (Twenty-third of the Lunar Calendar)

As shown in the G position in Figure 1, the relative positions of the sun, the earth, and the moon are once again at right angles, and what you see at this time The moon is bright in the east. The waning moon rises at midnight, hangs in the southern sky at sunrise, sets from the western horizon at noon, and is visible in the second half of the night.

8. The waning moon (from the 24th to the 30th of the lunar calendar is "dark")

At position H in Figure 1, the Emei moon faces east. The sun rises after midnight, the moon sets before dusk, and is visible before dawn.