What is the apparent trajectory of direct sunlight? What is the apparent trajectory of the sun on the equator?

The so-called apparent movement of the sun means that people on the earth always feel that the sun is rising and setting every day because of the rotation of the earth. In fact, this is of course not because the sun revolves around the earth, but a kind of "apparent motion", which can also be said to be a relative motion. The rotation direction of the earth is from west to east, so it looks as if the sun rises and sets.

From the distant star background, the sun seems to run on an imaginary celestial sphere, and this trajectory is called the ecliptic, and the thirteen constellations it passes through are the thirteen constellations of the ecliptic (the twelve constellations in astrology are another matter. First, grasp three situations and six regions. Because of the relationship between the apparent motion trajectory of the sun and the direct point of the sun, we can only analyze three cases of direct sunlight at the equator, the northern hemisphere and the southern hemisphere. The six regions divide the earth's surface into six regions, namely, equator, between straight point and latitude circle (hereinafter referred to as polar circle and vice versa), between straight point and polar circle, polar circle, polar circle and pole, and pole. 1. When the sun shines directly at the equator, the apparent trajectory of the global sun is basically the same except for the north and south poles, but the difference is that the altitude angle of the sun is different at noon. The specific analysis is as follows: The curve L 1~L3 in Figure 6 is the daily trajectory of the sun's apparent motion: the sun rises due east and sets due west, except for the north and south poles. The curve L 1 represents the apparent motion trajectory of the sun on the equator. At noon, the sun is overhead, and the sun is 90 degrees high. In fig. 7, it is the curve H 1. Curve L2 represents the apparent motion trajectory of the sun at the latitude between the equator and the South Pole. At noon, the sun is due north, and the altitude angle of the sun is less than 90 degrees. Curve L3 represents the apparent motion trajectory of the sun at the latitude between the equator and the North Pole. At noon, the sun is due south, and the altitude angle of the sun is less than 90 degrees. At this time, the north and south poles of the sun are always on the horizon, and the solar altitude angle is always zero. 2. When the sun shines directly into the northern hemisphere, ① the apparent motion trajectory of the sun on the equator is as shown in Figure 8, curve L 1, sunrise is in the northeast, sunset is in the northwest, and the sun is in the north at noon; ② The apparent trajectory of the sun between the direct point and the polar circle is shown in Figure 8, curve L3, with sunrise in the northeast, sunset in the northwest and the sun due south at noon; ③ The apparent trajectory of the sun between the direct point and the polar night circle is shown in Figure 8, curve L2, with sunrise in the northeast, sunset in the northwest and the sun in the north at noon; ④ The apparent motion track of the sun on the polar day circle is shown in curve L5 in Figure 8; ⑤ The apparent motion trajectory of the sun between the polar circle and the pole is shown as curve L4 in Figure 8; ⑥ The trajectory of the sun's apparent pole is a point, which is always located in the high altitude due south, with almost no fluctuation, as shown in Figure 9, straight line H4. 3. The sun shines directly in the southern hemisphere (the situation is similar to that in the northern hemisphere) ① The apparent motion track of the sun on the equator is as shown in figure 10, curve L 1, southeast of sunrise, southwest of sunset, and due south of the sun at noon; ② The apparent trajectory of the sun between the direct point and the polar circle is as shown in the curve L3 of Figure 10, with sunrise in the southeast, sunset in the southwest and the sun in the north at noon; (3) The apparent trajectory of the sun between the direct point and the polar night circle is shown in figure 10 curve L2, with sunrise in the southeast, sunset in the southwest and the sun due south at noon; (4) The apparent motion track of the sun on the polar day circle is shown in figure 10 curve L5; ⑤ The apparent motion trajectory of the sun between the polar circle and the pole is shown in figure 10 curve L4; ⑥ The trajectory of the sun's apparent pole is a point, which is always located in the high altitude due north, with almost no fluctuation, as shown in figure 1 1. Note: 1. There is no real sunrise or sunset from the latitude line (polar circle for short) where the extreme sun phenomenon just happened to the extreme point (including polar circle, excluding extreme point). Sunrise means sunset, and sunset occurs on the same day. Moreover, at sunrise and sunset, it is due north (northern hemisphere) or due south (southern hemisphere) (the solar altitude angle is the smallest in a day), and at noon, the sun is located due south (northern hemisphere) or due north (southern hemisphere) (the solar altitude angle is the largest in a day). At the same time, in this range (excluding the polar circle, including the poles), the daily variation of the solar altitude angle is no longer from zero. 2. When the sun shines directly into the northern hemisphere, except for one place-the North Pole and two moments-when there is an extreme sunrise and sunset, the apparent motion trajectory of the sun in the northern hemisphere is: (the following time is local time) located in the northeast before 6 o'clock, in the east at 6 o'clock and in the southeast at 6 o'clock ~ 12 hours ~. 3. When the sun shines directly into the southern hemisphere, except for one place-the South Pole and two moments-the sunrise and sunset with extreme diurnal phenomena, the apparent trajectory of the sun in the southern hemisphere is as follows: (The following times are all local time) It is located in the southeast before 6 o'clock, in the east at 6 o'clock, in the northeast at 6 o'clock ~ 12, and 12 ~ 650. & lt/FONT & gt； & lt/SPAN>。