rjxie 发表于 2003-12-16 13:25

[酷图] 火星的顺行、留和逆行照片！推荐！

Retrograde Mars
Credit & Copyright: Tunc Tezel
Explanation: Why would Mars appear to move backwards? Most of the time, the apparent motion of Mars in Earth's sky is in one direction, slow but steady in front of the far distant stars. About every two years, however, the Earth passes Mars as they orbit around the Sun. During the most recent such pass in August, Mars loomed particularly large and bright. Also during this time, Mars appeared to move backwards in the sky, a phenomenon called retrograde motion. Pictured above is a series of images digitally stacked so that all of the stars images coincide. Here, Mars appears to trace out a loop in the sky. At the top of the loop, Earth passed Mars and the retrograde motion was the highest. Retrograde motion can also be seen for other Solar System planets. In fact, by coincidence, the dotted line to the right of the image center is Uranus doing the same thing.

照片中小白点的轨迹是天王星在天球上的行进过程。

1900 发表于 2003-12-16 19:14

精彩！怎么拍的？合成的吗？

laonad 发表于 2003-12-17 12:45

herong987 发表于 2003-12-18 15:33

那串小的是什么？？？？

Melipal 发表于 2003-12-18 16:22

最初由 1900 发表
精彩！怎么拍的？合成的吗？

说明写的是电子合成

愚公 发表于 2003-12-18 23:00

那串小的是天王星

daily84 发表于 2003-12-20 08:56

好漂亮！！！！

昴星团 发表于 2003-12-20 21:56

好图!

HOTPOT 发表于 2003-12-21 15:55

nice!

阿找 发表于 2003-12-21 16:25

照片没反的话那火星是从哪边出发的呢?天王星呢?
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