Why do the sun and the moon sometimes appear in the sky at the same time?

The simultaneous appearance of the sun and the moon in the sky is caused by the different rotation periods of the earth around the sun and the moon around the earth.

This phenomenon is called the sun and the moon shining together, which is a natural phenomenon.

Direct observation of the sun, moon and sky with naked eyes requires certain conditions. Generally, it can only be seen in broad daylight when the sky is clear and the visibility is good from February/Kloc-0 to March in the autumn lunar calendar.

As long as two conditions are met, you can see the landscape where the sun and the moon appear at the same time. The first is the angular distance between them. Angular distance refers to the angle and distance between the sun and the moon in the sky. When the angle between them is between 120 degrees and 170 degrees, the first condition is satisfied when the distance is appropriate.

Secondly, it's sunny. If you want to see the sun and the moon in the sky at the same time, it must be sunny that day. After the gale began last night, the smog in the sky has been blown away, revealing a rare sunny day in the sky.

The sun and the moon are just natural phenomena, and they need to be above the horizon at the same time. Theoretically, as long as the atmospheric conditions are good, this phenomenon may occur except the fifteenth day of the lunar calendar.

But there is a second condition, that is, the limit magnitude of the sky (the darkest celestial body that can be seen) cannot be too low, so generally speaking, when the sun rises or is about to set, the brightness of the sky can easily meet this condition (even in cities).

So in the first half of the lunar calendar (after the fourth day of the lunar calendar), you can see the moon phase when the sun goes down, from west to east in turn.

In the second half of the lunar calendar (before the 27th), you can also see the moon after the sun rises, from the western sky to the eastern sky.

References:

Baidu encyclopedia-the sun and the moon shine together