如何在北半球确定东南西北方位,北极星或许是最便捷的自然指示物

时间:2019-07-15 来源:www.naturopatika.com

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地球的形状是一个三轴椭圆体,近似于一个真正的球体。我们可以看到地球是一个真正的球体。我们人类生活在这个领域的表面上。我们如何确定地球球面上的位置?在一个小区域内,我们可以使用周围的地理参考对象进行相对定位,如河流,山脉等可以作为定位的参考。

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使用Polaris确定位置

然而,如果难以在广泛的区域中定位地面参考物体,我们发现古代许多地图不准确,主要是因为定位不准确。现代地,对于地球表面上的点,我们主要使用绝对定位方法来定位,即纬度和经度位置,并使用经纬度线来指示东北和西南方向。

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地球自转

地球围绕地轴旋转。我们将地球轴和地球表面的两个交叉点定义为“北极”和“南极”。在地球表面,连接北极和南极的所有半圆都是经络。经线表示南北方向。垂直于地球轴线的所有平面与地球表面相交的是纬线,纬度线表示东西方向。所以问题在于我们在地球表面根本看不到地面上的经线和纬线,因为纬度和经度线对我们来说是虚构的。

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北极星

So how do we determine the location of a location? There are various methods, such as using the midday sun orientation to determine the local south or the north (relatively cumbersome, need to observe the shadow of the geographical things to calculate and determine), if we are in the northern hemisphere, we can also use the North Star to quickly determine the north position . The North Star is the northward extension of the Earth's rotation axis. The star pointed to it is also called "Gang Chenyi". It is about 434 light years away from the Earth and has a diameter of about 52 million kilometers, about four times the mass of the Sun. Because the Polaris is far from the Earth, its apparent magnitude is about 1.97, which doesn't look very bright.

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Polaris

Although the Polaris is not very bright, it is very special in the sky. Because the North Star is located on the northward extension of the Earth's axis, the position of the North Star in the sky is almost unchanged during the Earth's rotation, and other stars in the sky. They will rotate as the Earth rotates, and the center they surround is the "North Star." Therefore, in the sky, we only need to find the North Star, we can determine the local orientation, toward the North Star, pointing to the north direction, and then rotate 90 ° clockwise, you can get the "Southeast West" three directions.

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Big Dipper and Polaris

We look for the North Star in the sky and can use the position of the Big Dipper to determine it (as shown above). Of course, the use of Polaris for azimuth positioning can only be found in the northern hemisphere. If it is located in the southern hemisphere, the Earth's spherical surface will obscure the line of sight and the North Star cannot be seen. In addition, the use of Polaris can also determine the latitude of the location, the angle between the star and the ground plane in the sky is called the "elevation angle", then the "the number of elevation angles of the North Star" observed in a certain place is the latitude of the place.

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Can you find the North Star?

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