火星视角变化
[img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0807/mars0708_bosman.jpg[/img][color=blue][b]说明: 火星看起来始终如一吗？不，当地球与火星绕著太阳运行时，由地球上看火星的视直径会不断地改变。上图是2007年至2008年间，在荷兰的恩斯赫德(Enschede)以相同的放大率所拍摄到的30幅火星影像。当地球与火星位於太阳两侧时，火星看起来便小得多。相反地，当地球与火星接近时，火星的影像较大且明亮。近年来火星视角最大的日子发生在2003年八月的冲。由於火星与太阳的距离比地球与太阳的距离远，因此地球上的人们不会看到火星有盈亏的现象。上面的影像中也可以看到火星的北极冰帽，亮暗不同的土壤，云层，以及早期影像中的沙暴。下次的冲，也就是地球与火星再度接近时，将发生在2010年。 [/b][/color]
转自成大
[b]APOD20080714[/b]
[b]Changes in Angular Mars [/b]
[b]Credit & Copyright: [/b][url=http://www.astrofotografie.nl/][color=#0000ff]Richard Bosman[/color][/url]
[b]Explanation: [/b]Does Mars always appear the same? [url=http://en.wikipedia.org/wiki/No_sign][color=#0000ff]No.[/color][/url] As both Earth and Mars orbit the Sun, the [url=http://chandra.harvard.edu/photo/scale.html][color=#0000ff]apparent angular size[/color][/url] of Mars changes as viewed from the Earth. [url=http://www.astrofotografie.nl/Mars.htm][color=#0000ff]Pictured above[/color][/url] from [url=http://en.wikipedia.org/wiki/Enschede][color=#0000ff]Enschede[/color][/url], [url=http://en.wikipedia.org/wiki/Netherlands][color=#0000ff]Holland[/color][/url], Mars was captured in 2007 and 2008 with 30 separate images, all taken with the same magnification. When [url=http://antwrp.gsfc.nasa.gov/apod/ap070325.html][color=#0000ff]Earth[/color][/url] and [url=http://antwrp.gsfc.nasa.gov/apod/ap010718.html][color=#0000ff]Mars[/color][/url] are on opposite sides of the Sun, Mars appears relatively small. Conversely, when Earth and Mars are near each other, [url=http://antwrp.gsfc.nasa.gov/apod/ap030813.html][color=#0000ff]Mars looms[/color][/url] large and bright. The largest [url=http://www.dustymars.net/Observing_Mars.html][color=#0000ff]Mars[/color][/url] has appeared in recent history was the [url=http://antwrp.gsfc.nasa.gov/apod/ap030828.html][color=#0000ff]opposition of August 2003[/color][/url]. Since Mars is always more distant from the Earth from the Sun, [url=http://antwrp.gsfc.nasa.gov/apod/ap031112.html][color=#0000ff]Mars[/color][/url] never shows a crescent phase to Earthlings. [url=http://antwrp.gsfc.nasa.gov/apod/ap990705.html][color=#0000ff]Visible[/color][/url] also in the above images are the [url=http://antwrp.gsfc.nasa.gov/apod/ap021224.html][color=#0000ff]north polar cap of Mars[/color][/url], dark and light soil, clouds, and, in the early images, a global [url=http://antwrp.gsfc.nasa.gov/apod/ap011017.html][color=#0000ff]dust storm[/color][/url]. The [url=http://www.seds.org/~spider/spider/Mars/marsopps.html][color=#0000ff]next opposition[/color][/url], when Earth again passes near to Mars, will occur in early 2010.
[[i] 本帖最后由 Eldghost 于 2008-7-14 22:44 编辑 [/i]] 又偷人家的东西!
::070821_05.jpg:: 呵呵，不知道古人又会由此产生哪些联想。。。行星占的范畴。。。 [quote]原帖由 [i]cool_sky[/i] 于 2008-7-14 20:55 发表 [url=http://www.astronomy.com.cn/bbs/redirect.php?goto=findpost&pid=977787&ptid=93952][img]http://www.astronomy.com.cn/bbs/images/common/back.gif[/img][/url]
又偷人家的东西!
::070821_05.jpg:: [/quote]
图版的图文都是有标注来源的，呵呵
回复 2# cool_sky 的帖子
照i这样说成大 北馆都是偷了。。::070821_17.jpg::页:
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