2009年7月22日 日全食--1.3 日蚀轨迹的正射投影地图

原帖见：http://www.astronomy.com.cn/bbs/thread-111450-1-1.html
原文见：http://eclipse.gsfc.nasa.gov/SEpubs/20090722/TP214169a.pdf


因為不是本科系，雖然參看了相關資料，但....仍然不夠專業，有些意思也不懂，用紅字標明。如果有錯誤的地方，請專業領域的指正，謝謝~~






    Figure 1 is an orthographic projection map of Earth (adapted from Espenak 1987) showing the path of penumbral (partial eclipse) and umbral (total eclipse) shadows. The day- light terminator is plotted for the instant of greatest eclipse with north at the top. The sub-Earth point is centered over the point of greatest eclipse and is indicated with an asterisk symbol. The subsolar point (Sun in zenith) at that instant is also shown.


    表一是地球的正投影原理圖(1987，Espenak 改編)，半影(部分日蝕)和本影(全日蝕)的路徑。瞬間的最大日蝕點(Greatest eclipse)在北邊頂點。星下點(or 次地緯度)在最大日時點，有星號註記，瞬間的日下點(subsolar，太陽於天頂) 也有標示。




   The limits of the Moon’s penumbral shadow define the region of visibility of the partial eclipse. This saddle-shaped region often covers more than half of Earth’s daylight hemi- sphere and consists of several distinct zones or limits. At the northern and/or southern boundaries lie the limits of the pen- umbra’s path. Partial eclipses have only one of these limits, as do central eclipses when the shadow axis falls no closer than about 0.45 radii from Earth’s center. Great loops at the west-areas where the eclipse begins and ends at sunrise and sunset,respectively. In the case of the 2009 eclipse, the penumbra has both a northern and southern limit, so that the rising and setting curves form two separate, closed loops. Bisecting the “eclipse begins and ends at sunrise and sunset” loops is the curve of maximum eclipse at sunrise (western loop) and sunset (eastern loop). The exterior tangency points P1 and P4 mark the coordinates where the penumbral shadow first contacts (partial eclipse begins) and last contacts (partial eclipse ends) Earth’s surface. The path of the umbral shadow bisects the penumbral path from west to east.



    位於半影區的國家可看見日偏蝕。這些國家呈現馬鞍狀，涵蓋超過半球的白晝國家，包含一些國家的區域或範圍。北邊和南邊的邊界劃出半影的路線。日偏蝕只有一個路線，中心蝕….陰影的中心距離地球中心0.45半徑。Great loops 在西邊，日蝕開始於日出方位，結束於日落方位。2009年日蝕，半影區分成北邊和南邊，開始與結束的曲線圖(curves)分成兩個圖表(loops)。劃分”日蝕開始於日出方位、結束於日落方位”的圖表(loops)就是日出方位的食甚(西方loop)和日落方位的食甚(東方loop)的曲線圖(curve)。地球表面相切點P1
和 P4標示出第一接觸(日蝕開始)和最後接觸(日蝕結束)。陰影的路線將半影的路線分作西方和東方兩部分。
     


    The limits of the Moon’s penumbral shadow define the region of visibility of the partial eclipse. This saddle-shaped region often covers more than half of Earth’s daylight hemi- sphere and consists of several distinct zones or limits. At the northern and/or southern boundaries lie the limits of the pen- umbra’s path. Partial eclipses have only one of these limits, as do central eclipses when the shadow axis falls no closer than about 0.45 radii from Earth’s center. Great loops at the west-areas where the eclipse begins and ends at sunrise and sunset, respectively. In the case of the 2009 eclipse, the penumbra has both a northern and southern limit, so that the rising and setting curves form two separate, closed loops. Bisecting the “eclipse begins and ends at sunrise and sunset” loops is the curve of maximum eclipse at sunrise (western loop) and sunset (eastern loop). The exterior tangency points P1 and P4 mark the coordinates where the penumbral shadow first contacts (partial eclipse begins) and last contacts (partial eclipse ends) Earth’s surface. The path of the umbral shadow bisects the penumbral path from west to east.

    食甚的圖表是所有點的軌跡，在世界時間食甚出現。宇宙時間每半小時紀錄一次，方位從北至南。陰影的變化，世界時間每十分鐘紀錄。不同階段的食分描繪出所有點的軌跡圖表，食甚的食分是固定的，發生在日出與日落的食甚之間。而且，幾乎和南方的半影區平行，食分0.0，接著是0.2, 0.4, 0.6, 0.8。北方和南方全食帶，食分1.0。



A curve of maximum eclipse is the locus of all points where the eclipse is at maximum at a given time. They are plotted at each half hour in Universal Time, and generally run in a north-south direction. The outline of the umbral shadow is plotted every 10 min in Universal Time. Curves of constant eclipse magnitude2
delineate the locus of all points where the magnitude at maximum eclipse is constant. These curves run exclusively between the curves of maximum eclipse at sunrise and sunset. Furthermore, they are quasi-parallel to the southern penumbral limit. This limit may be thought of as a curve of constant magnitude of 0.0, while the adjacent curves are for magnitudes of 0.2, 0.4, 0.6, and 0.8. The northern and south- ern limits of the path of total eclipse are curves of constant magnitude of 1.0.


    表一的頂端，月亮和太陽在黃道坐標(新月頃刻) 地心交會，發生於頃刻的食甚。最大日蝕點就是日全蝕。當月球直徑和太陽重疊。Gamma是…….(不懂它的意思，查到相關資料：Gamma可以說是表達Greatest Eclipse及Sub Solar兩點之間距離的一個系數)。日蝕的沙羅周期具有周期性。




註  
2.  eclipse  magnitude2    食分是月球掩蓋著太陽直徑之比率

虽然繁体字大陆的朋友看着累，但仍感谢LZ的支持！

謝謝提醒~
word軟體有個功能可以中翻簡，簡翻中，
我的word2003沒有XD