APOD 090411-12 巨大的星云图、天鹅座疏散星团M39

http://apod.nasa.gov/apod/astropix.html

2009 April 11
The Big Picture

                               
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Credit & Copyright: Dennis di Cicco (TWAN) & Sean Walker, Skyandtelescope.com
Explanation:
Intricate, glowing nebulae that shine in planet Earth's night sky are beautiful to look at in deep images made with telescopes and sensitive cameras. But they are faint and otherwise invisible to the naked-eye. That makes their relative location and extent on the sky difficult to appreciate. So, consider this impressive composite image of a wide region of the northern winter sky. With a total exposure time of 40 hours, the painstaking mosaic presents a nebula-rich expanse known as the Orion-Eridanus Superbubble above a house in suburban Boston, USA. Within the wide and deep view are nebulae more often seen in narrower views, including the Great Orion Nebula, the Rosette Nebula, the Seagull Nebula, the California Nebula, and Barnard's Loop. The familiar constellation of Orion itself is just above the foreground house. Brightest star Sirius is left of the roof, and the recognizable Pleiades star cluster is above the tree at the right. A version of the big picture that includes simple constellation guidelines is available here.

成大的翻译
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/apod.html

巨幅的星空掛圖
影像版權與提供:Dennis di Cicco (TWAN) & Sean Walker,Skyandtelescope.com

說明:
在用望遠鏡和高感度相機所拍攝的深空影像裡，常會出現地球夜空中賞心悅目的纖細美麗星雲。不過這些天體都很黯淡，因此肉眼不得見，所以我們對他們在天空的相對位置和大小通常相當陌生。不過上面這幅呈現北天冬季星空的大範圍精彩組合影像，或許有助於緩解上述的問題。這張費盡心思的組合影像總曝光時間為40小時，它呈現了美國波斯頓郊區的一座住宅和它上空稱為獵戶-波江超級泡泡這個擁有眾多星雲的天區。這幅廣角深空影像有許多特寫影像常呈現的天體，其中包括獵戶座大星雲、薔薇星雲、海鷗星雲和巴納德圈等。我們很熟悉的獵戶座在比前景房屋屋頂稍高一些的位置，天狼星在屋頂的左側，而昴宿星團則在右側樹梢的上頭。點選此處，可以帶出標示有簡單星座邊界的另一版本掛圖。

本图就这么大，780x780就是最大
台湾与我们的翻译有些不同，我这里把我们的翻译出一下

Great Orion Nebula   猎户座大星云

Rosette Nebula  玫瑰星云

Seagull Nebula   海鸥星云

California Nebula  加州星云（样子像加利福尼亚州）

Barnard's Loop   巴纳德环

参考这个链接http://www.astronomy.com.cn/bbs/viewthread.php?extra=page%3D11%26amp%3Bfilter%3D0%26amp%3Borderby%3Ddateline&tid=82605

APOD又在炒冷饭了，把2007.11的东西再次翻出来，而且这次居然是黑白的。

APOD 090412 天鹅座疏散星团 M39
2009 April 12
M39: Open Cluster in Cygnus

                               
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Credit: Heidi Schweiker,WIYN,NOAO,AURA,NSF
Explanation:
Lying just at the limit of human perception is a picturesque starfield containing one of the larger open clusters on the northern sky. Spanning an angle larger than the Moon, M39's relatively few stars lie only about 800 light years distant toward the constellation of Cygnus. The above picture of M39 is a mosaic of 33 images taken by the WIYN telescope on Kitt Peak in Arizona, USA. The stars in M39 are all about 300 million years old, much younger than the 5,000 million years of our Sun. Open clusters, also called galactic clusters, contain fewer and younger stars than globular clusters. Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy.

本楼为成大的翻译

M39: 天鵝座的疏散星團
影像提供: Heidi Schweiker, WIYN, NOAO, AURA, NSF

說明:  亮度剛好在人類視覺極限的M39，是北方天空一個很美麗的大型疏散星團。位在北天 天鵝座內的M39，離我們約有800光年遠，它內部為數不多的恆星分佈在比滿月略大的天區。上面這張M39的影像，是從33幅WIYN望遠鏡照片所組成出來的，拍攝地點是美國．亞利桑那州的基特峰 (Kitt Peak)。M39成員星的年齡大約都是三億年，遠比大陽的五十億年要年輕。疏散星團也稱為銀河星團，它們的成員星比球狀星團年輕，數量也較少。另一項異於球狀星團的特點是，疏散星團通常位在銀河系的盤面上。

不好意思，今天的APOD只有1024大小的图，大家将就一下吧。

                               
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天鹅  M39   ，看了 THX

天鹅座的两个梅西耶天体之一