Definition of the solar ecliptic longitude and the yellow red angle

Yellow longitude: The Earth orbits the Sun for about 365 days and 5 hours, and travels 94,000 kilometers. This orbit is known as the ecliptic longitude of the sun.

Yellow-red angle of intersection: The angle of the earth's orbital plane (ecliptic plane) and the equatorial plane (celestial equatorial plane), also known as the sun's declination angle.

The magnitude of the yellow-red angle determines the movement and movement law of the direct point of the sun, and determines the degree of the Tropic of Cancer.

Since the current yellow-red angle is 23°26, the latitude of the Tropic of Cancer is 23°26. The latitude of the Arctic and Antarctic Circles is 90°-23°26 and 66°34. The division of the five belts on the earth is bounded by these two lines, that is, between the Tropic of Cancer and the Tropic of Capricorn because of the opportunity for direct sunlight, it is tropical.

The Tropic of Cancer and the Polar Circle are temperate zones and are transitional zones. Within the Arctic and Antarctic Circles, it is a cold zone because of its polar night phenomenon.

Therefore, if the yellow-red angle becomes smaller, the tropical range becomes smaller, and the yellow-red angle becomes larger, then the position of the direct point of the sun will also change accordingly, and the direct point will exceed the current northernmost and southernmost limits (23°26), and the polar line (66°34) will also approach the equator, so the heat obtained by the surface will change with time and space. As a result, the temperate zone is narrowed. Since the polar range increases, so does the range of the polar day and night.

Report. Human supplement 2009-09-19 10:41The yellow-red angle is 23 degrees 26 minutes, and the Tropic of Cancer is also 23 degrees 26 minutes in the south (north). In this area, the direct sunlight is the zone, that is, the tropics.

If the angle of the Tropic of Cancer becomes larger, the latitude of the Tropic of Cancer will also become larger, so the tropical range will become larger.

The Earth orbits the Sun for about 365 days and 5 hours, orbiting 9400000 kilometers, and this orbit is called the solar ecliptic longitude.

The ecliptic of the earth around the celestial sphere is about 365 days 5 hours 48 minutes 46 seconds, the earth's revolution is manifested as the annual apparent movement of the sun in the view of the earth, its running line is called the ecliptic, the ecliptic longitude is the measurement coordinates on the ecliptic, according to astronomical conventions, the vernal equinox point is measured from west to east from west to east, divided into 360 degrees, the ancients of our country divided the 360 degrees of the sun's ecliptic longitude into 24 equal parts, each part of 15 degrees, for a solar term, the number of days between the two solar terms is about 15 days, there are 24 solar terms throughout the year.

Ecliptic longitude refers to the longitude of the sun or the longitude of the celestial sphere, which is a coordinate value used in the ecliptic coordinate system to determine the position of the celestial body on the celestial sphere. In this system, the celestial sphere is divided by the plane of the celestial equator into two hemispheres, the ecliptic which is the path of the Sun across the celestial sphere during the year, crossing the celestial equator twice in a year, once at the vernal equinox and the other at the autumnal equinox.

Since there is no obvious point on the ecliptic that can be used as the ecliptic longitude of 0 degrees, the vernal equinox point of Zaoqiao is arbitrarily designated as the position of 0 degrees of ecliptic longitude, and the ecliptic longitude of the celestial body is the angular distance from the celestial cavity to the vernal equinox measured eastward. Ecliptic coordinates are very useful for the celestial bodies of the solar system. For example, the solar longitude given in the almanac is measured in the ecliptic longitude.

The Earth orbits the Sun about 365 days and 5 hours a day, orbiting 94,000 kilometers. This orbit is known as the ecliptic longitude of the sun.

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Problem description: When the solar ecliptic longitude is 225 degrees and 270 degrees, what is the angle between the shadow of the building and the ground in Zhengzhou??? Thank you!!!

Analysis: The ecliptic longitude of the sun at 225 degrees and 270 degrees is the beginning of winter and the winter solstice, respectively.

The angle between the shadow of the building and the ground in Zhengzhou City" is a bit difficult to understand.

You mean the midday solar elevation angle, right?

For a location on Earth, the height of the sun is the angle between the direction of incidence of sunlight and the ground level. We use h to denote this angle, which is numerically equal to the horizon height of the Sun in the celestial horizon coordinate system.

The solar altitude angle changes with local time and the declination of the sun. The declination of the sun is expressed in δ, and the geography of the place of observation.

Latitude is denoted by , local time (hour angle) is denoted by t, and there is a formula for calculating the solar altitude angle:

sin h＝sin φ sin δ＋sin φ cos δ cos t

Sunrise and sunset, the angle of sun elevation in the same place is constantly changing throughout the day. The angle at sunrise and sunset is zero degrees, positive.

The solar altitude angle is greatest at noon.

The hour angle at noon is 0, and the above formula can be simplified to:

sin h＝sin φ sin δ＋sin φ cos δ

where h is the noon solar altitude angle.

From the trigonometric formula of the sum and difference of the two angles, it can be obtained.

sin h＝cos(φ－

Thus, for the Northern Hemisphere, h 90° (

For the southern hemisphere, h 90° (

The latitude of Zhengzhou is about 35 degrees north latitude.

Hope mine is helpful to you.

It is precisely because of the existence of the yellow-red angle that the direct solar point will make a periodic regression movement between the Tropic of Cancer, causing the annual change of solar radiation, and then the four seasons and the division of the five zones.

The yellow-equatorial angle is the angle between the earth's orbital plane (ecliptic plane) and the equatorial plane (celestial equatorial plane), also known as the equatorial elongation. The current angle of the Earth's yellow-red intersection is about 23°26'。

With the presence of the yellow-red angle, the northernmost limit of the direct point of the sun is 23°26 N, that is, the Tropic of Cancer; The southernmost limit is 23°26 s, that is, the Tropic of Capricorn, that is, the point of direct sunlight moves back and forth at 23°26 s and 23°26 n. As a result, the amount of heat gained by the surface changes with time and space. Such changes are based on temporal and spatial variations in the length of day and night and the height of the sun at noon.

Assuming that the yellow-red angle increases, the position of the direct point of the sun will also change accordingly, and the direct point will exceed the current northernmost and southernmost limits (23°26), resulting in a larger tropics. The polar line (66°34) expands, so that the heat gained by the surface changes over time and space. As a result, the cold zone is more extensive.

As the polar range increases, so does the polar day.

The larger this angle, the greater the range of activity of the direct point of the sun on the earth's surface, that is, the middle tropics will be larger; Otherwise, it will be smaller.

The Earth orbits the Sun for more than 365 days and 5 hours, and travels 94,000 kilometers. This orbit is known as the ecliptic longitude of the sun and is divided into 360°.

Divide 360° into 24 equal parts, 15° per minute, for a solar term. The number of days between the two solar terms is about 15 days, and there are 24 solar terms in the whole year.

Twenty-four solar terms, where the earth is located, the solar yellow longitude, the solar term, the solar yellow longitude, the month, the date of occurrence, the beginning of spring).

Rain 330 2 19(20).

Stinging 345 3 6(5).

Vernal equinox ) Qingming ).

Gu Yu ) Lixia ).

Xiaoman) miscanthus species).

Summer solstice 90 6 22 (21).

Xiaoxiao 105 7 7(8).

Great heat 120 7 23(24).

Beginning of autumn ) 150 8 23 (24).

White dew ) autumnal equinox 180 9 23 (24).

Hanlu 195 10 8(9).

Frostfall 210 10 24 (23).

Lidong 225 11 8(7).

Light Snow 240 11 23(22).

Heavy Snow 255 12 7(8).

Winter solstice 270 12 22 (23).

Xiaohan 285 1 6(5).

Dahan 300 1 20(21).

If the ecliptic is coincident with the equator, then the direct point of the sun will always be on the equator and will not move north and south.

But in fact, the yellow and red coincide, the earth tilts and rotates, and the existence of the yellow and red angles causes the north-south movement of the direct sun point, and its north-south boundary is the degree of the yellow-red angle, which is called the Tropic of Cancer.