Depending on the season and phase, the moon sets behind the horizon in the west, southwest or northwest. This is due to the fact that the Sun sets strictly in the west only on the days of the spring and autumn equinox. The closer to the solstice, the setting luminary will be located further south or north on the horizon. Since the position of the Moon in the sky is related to its location relative to the Earth and the daylight, then it will set in different ways.
How does the moon's phase and season affect the setting of the moon?
The moon is visible in the sky because the sun illuminates it. The phases of the moon depend on the position of the night star relative to the Earth and the Sun. During a full moon, the Sun, Earth and its satellite are in line. At the same time, the Moon occupies the position farthest from the Sun, and when the daylight rises, the night one begins to set.
On the contrary, on a new moon, the Moon "rises" and "sets" behind the horizon together with the Sun. At the same time, it is not visible to the naked eye, since it is completely covered by the shadow of the Earth.
The Earth's axis is tilted relative to the planet's orbit by 23.5 degrees. When moving around the Sun during the year, the planet turns to the luminary with one or the other side. This, in turn, gives rise to the change of seasons, and during each season the Sun changes its trajectory across the sky.
Since with the change of seasons the Sun changes its position and movement in the sky relative to the horizon, the Moon will appear on the dome of the sky and disappear from it at different times and in different places.
In this case, one should take into account the difference in the seasons in the northern and southern hemispheres.
How to predict the setting of the moon
You can predict where the lunar sunset will be observed by focusing on the Sun. Every day the Moon lags behind the Sun by 12 degrees, sliding across the sky also in an easterly direction. This means that the time it lags behind the Sun is 50 minutes per day.
The earth spins from west to east, clockwise. Therefore, everything that you observe in the sky moves along it in the opposite direction, from east to west: stars, the sun, the moon and planets.
If on a new moon the Moon sets behind the horizon in the same place as the Sun, and also simultaneously with it, then in other phases the place and time of the lunar sunset will differ from the solar one, depending on the degree of the Moon's lag.
In a young month, the thin horn of the Moon is visible above the horizon when the Sun has already set. The first quarter of the Moon coincides with the position of the night star 90 degrees to the left of the Sun. Then, if the Sun has set in the southwest, then the Moon will set behind the horizon in the west. This happens in the northern hemisphere in winter, and in the southern hemisphere in summer.
The location of the moonset relative to the horizon also depends on the degree of latitude.
The Full Moon is 180 degrees to the left of the Sun and is 12 hours behind it. During sunset, the moon rises. And if in the northern hemisphere the winter sun sets in the southwest, then the moon will disappear beyond the horizon in the northwest.
The aging Moon in the last quarter is 270 degrees to the left of the Sun and appears in the sky 18 hours later. Its sunset will coincide with noon. In winter and summer in the northern hemisphere, it will happen in the west, in the spring in the southwest, and in the fall in the northwest.
