图片：七姐妹星团_天文吧

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图片：七姐妹星团

那团漂亮得蓝色天体就是昴宿星团，也叫“七姐妹星团”或M45。昴宿星团是天空最耀眼，最容易辨认的疏散星团。昴宿星团包含3,000多个恒星，距离我们约为400光年，直径仅长13光年。围绕这些恒星的是一个由细微粉尘构成的蓝色反射星云。左下方偏红色的星体即是“加利福利亚星云”，她的形状与加利福利亚州相似，故而得此名。加利福利亚星云又叫NGC 1499，比昴宿星团昏暗一些，因而更加难以辨认。这团红色的，正在膨胀的氢气距离我们约1,500光年。尽管两者之间足够放下25个满月，但是这张广角，深空合成图片还是能够把她们都囊括进去。
翻译：Aino
2009年11月上旬
http://antwrp.gsfc.nasa.gov/apod/ap091103.html

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1楼2009-11-09 18:44回复

Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2009 November 3
Seven Sisters Versus California
Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)
Explanation: On the upper right, dressed in blue, is the Pleiades. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across. Surrounding the stars is a spectacular blue reflection nebula made of fine dust. A common legend is that one of the brighter stars faded since the cluster was named. On the lower left, shining in red, is the California Nebula. Named for its shape, the California Nebula is much dimmer and hence harder to see than the Pleiades. Also known as NGC 1499, this mass of red glowing hydrogen gas is about 1,500 light years away. Although about 25 full moons could fit between them, the above wide angle, deep field image composite has captured them both.

2楼2009-11-09 18:45